Abstract

We characterized experimental artifacts arising from the non-linear response of acousto-optical deflectors (AODs) in an ultra-fast force-clamp optical trap and have shown that using electro-optical deflectors (EODs) instead eliminates these artifacts. We give an example of the effects of these artifacts in our ultra-fast force clamp studies of the interaction of myosin with actin filaments. The experimental setup, based on the concept of Capitanio et al. [Nat. Methods 9, 1013–1019 (2012)] utilizes a bead-actin-bead dumbbell held in two force-clamped optical traps which apply a load to the dumbbell to move it at a constant velocity. When myosin binds to actin, the filament motion stops quickly as the total force from the optical traps is transferred to the actomyosin attachment. We found that in our setup, AODs were unsuitable for beam steering due to non-linear variations in beam intensity and deflection angle as a function of driving frequency, likely caused by low-amplitude standing acoustic waves in the deflectors. These aberrations caused instability in the force feedback loops leading to artifactual jumps in the trap position. We demonstrate that beam steering with EODs improves the performance of our instrument. Combining the superior beam-steering capability of the EODs, force acquisition via back-focal-plane interferometry, and dual high-speed FPGA-based feedback loops, we apply precise and constant loads to study the dynamics of interactions between actin and myosin. The same concept applies to studies of other biomolecular interactions.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

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References

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  1. S. M. Block, L. S. B. Goldstein, and B. J. Schnapp, “Bead movement by single kinesin molecules studied with optical tweezers,” Nature 348(6299), 348–352 (1990).
    [Crossref] [PubMed]
  2. A. D. Mehta, R. S. Rock, M. Rief, J. A. Spudich, M. S. Mooseker, and R. E. Cheney, “Myosin-V is a processive actin-based motor,” Nature 400(6744), 590–593 (1999).
    [Crossref] [PubMed]
  3. T. Nishizaka, H. Miyata, H. Yoshikawa, S. Ishiwata, and K. Kinosita., “Unbinding force of a single motor molecule of muscle measured using optical tweezers,” Nature 377(6546), 251–254 (1995).
    [Crossref] [PubMed]
  4. G. J. L. Wuite, S. B. Smith, M. Young, D. Keller, and C. Bustamante, “Single-molecule studies of the effect of template tension on T7 DNA polymerase activity,” Nature 404(6773), 103–106 (2000).
    [Crossref] [PubMed]
  5. A. Ashkin, J. M. Dziedzic, J. E. Bjorkholm, and S. Chu, “Observation of a single-beam gradient force optical trap for dielectric particles,” Opt. Lett. 11(5), 288–290 (1986).
    [Crossref] [PubMed]
  6. F. Gittes and C. F. Schmidt, “Interference model for back-focal-plane displacement detection in optical tweezers,” Opt. Lett. 23(1), 7–9 (1998).
    [Crossref] [PubMed]
  7. S. F. Tolić-Nørrelykke, E. Schäffer, J. Howard, F. S. Pavone, F. Jülicher, and H. Flyvbjerg, “Calibration of optical tweezers with positional detection in the back focal plane,” Rev. Sci. Instrum. 77(10), 103101 (2006).
    [Crossref]
  8. M. J. Lang, C. L. Asbury, J. W. Shaevitz, and S. M. Block, “An Automated Two-Dimensional Optical Force Clamp for Single Molecule Studies,” Biophys. J. 83(1), 491–501 (2002).
    [Crossref] [PubMed]
  9. M. T. Valentine, N. R. Guydosh, B. Gutiérrez-Medina, A. N. Fehr, J. O. Andreasson, and S. M. Block, “Precision steering of an optical trap by electro-optic deflection,” Opt. Lett. 33(6), 599–601 (2008).
    [Crossref] [PubMed]
  10. M. Bugiel, A. Jannasch, and E. Schäffer, “Implementation and Tuning of an Optical Tweezers Force-Clamp Feedback System,” in Optical Tweezers, Methods in Molecular Biology (Humana Press, New York, NY, 2017), pp. 109–136.
  11. K. Visscher, M. J. Schnitzer, and S. M. Block, “Single kinesin molecules studied with a molecular force clamp,” Nature 400(6740), 184–189 (1999).
    [Crossref] [PubMed]
  12. Y. Takagi, E. E. Homsher, Y. E. Goldman, and H. Shuman, “Force Generation in Single Conventional Actomyosin Complexes under High Dynamic Load,” Biophys. J. 90(4), 1295–1307 (2006).
    [Crossref] [PubMed]
  13. J. T. Finer, R. M. Simmons, and J. A. Spudich, “Single myosin molecule mechanics: piconewton forces and nanometre steps,” Nature 368(6467), 113–119 (1994).
    [Crossref] [PubMed]
  14. C. Veigel, L. M. Coluccio, J. D. Jontes, J. C. Sparrow, R. A. Milligan, and J. E. Molloy, “The motor protein myosin-I produces its working stroke in two steps,” Nature 398(6727), 530–533 (1999).
    [Crossref] [PubMed]
  15. M. Capitanio, M. Canepari, M. Maffei, D. Beneventi, C. Monico, F. Vanzi, R. Bottinelli, and F. S. Pavone, “Ultrafast force-clamp spectroscopy of single molecules reveals load dependence of myosin working stroke,” Nat. Methods 9(10), 1013–1019 (2012).
    [Crossref] [PubMed]
  16. J. R. Sellers, “Myosins: a diverse superfamily,” Biochim. Biophys. Acta 1496(1), 3–22 (2000).
    [Crossref] [PubMed]
  17. M. J. Greenberg, H. Shuman, and E. M. Ostap, “Inherent Force-Dependent Properties of β-Cardiac Myosin Contribute to the Force-Velocity Relationship of Cardiac Muscle,” Biophys. J. 107(12), L41–L44 (2014).
    [Crossref] [PubMed]
  18. W. H. Guilford, D. E. Dupuis, G. Kennedy, J. Wu, J. B. Patlak, and D. M. Warshaw, “Smooth muscle and skeletal muscle myosins produce similar unitary forces and displacements in the laser trap,” Biophys. J. 72(3), 1006–1021 (1997).
    [Crossref] [PubMed]
  19. J. M. Muretta, K. J. Petersen, and D. D. Thomas, “Direct real-time detection of the actin-activated power stroke within the myosin catalytic domain,” Proc. Natl. Acad. Sci. U.S.A. 110(18), 7211–7216 (2013).
    [Crossref] [PubMed]
  20. J. A. Rohde, D. D. Thomas, and J. M. Muretta, “Heart failure drug changes the mechanoenzymology of the cardiac myosin powerstroke,” Proc. Natl. Acad. Sci. U.S.A. 114(10), E1796–E1804 (2017).
    [Crossref] [PubMed]
  21. A. Tempestini, C. Monico, L. Gardini, F. Vanzi, F. S. Pavone, and M. Capitanio, “Sliding of a single lac repressor protein along DNA is tuned by DNA sequence and molecular switching,” Nucleic Acids Res. 46, gky208 (2018).
    [PubMed]
  22. V. M. Demidov, S. K. Tripathy, F. I. Ataullakhanov, and E. L. Grishchuk, “Ultrafast Force-Clamp Spectroscopy Reveals “Sliding” Catch-Bond Behavior of the Microtubule-Binding NdC80 Protein,” Biophys. J. 114(3), 382a (2018).
    [Crossref]
  23. G. R. B. E. Römer and P. Bechtold, “Electro-optic and Acousto-optic Laser Beam Scanners,” Phys. Procedia 56, 29–39 (2014).
    [Crossref]
  24. Conoptics Inc, “Optical Trapping Deflection Systems,” http://www.conoptics.com/optical-trapping-deflection-systems/ .
  25. A. E. Wallin, H. Ojala, E. Hæggström, and R. Tuma, “Stiffer optical tweezers through real-time feedback control,” Appl. Phys. Lett. 92(22), 224104 (2008).
    [Crossref]
  26. Goutzoulis, Design and Fabrication of Acousto-Optic Devices (CRC Press, 1994).

2018 (2)

A. Tempestini, C. Monico, L. Gardini, F. Vanzi, F. S. Pavone, and M. Capitanio, “Sliding of a single lac repressor protein along DNA is tuned by DNA sequence and molecular switching,” Nucleic Acids Res. 46, gky208 (2018).
[PubMed]

V. M. Demidov, S. K. Tripathy, F. I. Ataullakhanov, and E. L. Grishchuk, “Ultrafast Force-Clamp Spectroscopy Reveals “Sliding” Catch-Bond Behavior of the Microtubule-Binding NdC80 Protein,” Biophys. J. 114(3), 382a (2018).
[Crossref]

2017 (1)

J. A. Rohde, D. D. Thomas, and J. M. Muretta, “Heart failure drug changes the mechanoenzymology of the cardiac myosin powerstroke,” Proc. Natl. Acad. Sci. U.S.A. 114(10), E1796–E1804 (2017).
[Crossref] [PubMed]

2014 (2)

G. R. B. E. Römer and P. Bechtold, “Electro-optic and Acousto-optic Laser Beam Scanners,” Phys. Procedia 56, 29–39 (2014).
[Crossref]

M. J. Greenberg, H. Shuman, and E. M. Ostap, “Inherent Force-Dependent Properties of β-Cardiac Myosin Contribute to the Force-Velocity Relationship of Cardiac Muscle,” Biophys. J. 107(12), L41–L44 (2014).
[Crossref] [PubMed]

2013 (1)

J. M. Muretta, K. J. Petersen, and D. D. Thomas, “Direct real-time detection of the actin-activated power stroke within the myosin catalytic domain,” Proc. Natl. Acad. Sci. U.S.A. 110(18), 7211–7216 (2013).
[Crossref] [PubMed]

2012 (1)

M. Capitanio, M. Canepari, M. Maffei, D. Beneventi, C. Monico, F. Vanzi, R. Bottinelli, and F. S. Pavone, “Ultrafast force-clamp spectroscopy of single molecules reveals load dependence of myosin working stroke,” Nat. Methods 9(10), 1013–1019 (2012).
[Crossref] [PubMed]

2008 (2)

A. E. Wallin, H. Ojala, E. Hæggström, and R. Tuma, “Stiffer optical tweezers through real-time feedback control,” Appl. Phys. Lett. 92(22), 224104 (2008).
[Crossref]

M. T. Valentine, N. R. Guydosh, B. Gutiérrez-Medina, A. N. Fehr, J. O. Andreasson, and S. M. Block, “Precision steering of an optical trap by electro-optic deflection,” Opt. Lett. 33(6), 599–601 (2008).
[Crossref] [PubMed]

2006 (2)

S. F. Tolić-Nørrelykke, E. Schäffer, J. Howard, F. S. Pavone, F. Jülicher, and H. Flyvbjerg, “Calibration of optical tweezers with positional detection in the back focal plane,” Rev. Sci. Instrum. 77(10), 103101 (2006).
[Crossref]

Y. Takagi, E. E. Homsher, Y. E. Goldman, and H. Shuman, “Force Generation in Single Conventional Actomyosin Complexes under High Dynamic Load,” Biophys. J. 90(4), 1295–1307 (2006).
[Crossref] [PubMed]

2002 (1)

M. J. Lang, C. L. Asbury, J. W. Shaevitz, and S. M. Block, “An Automated Two-Dimensional Optical Force Clamp for Single Molecule Studies,” Biophys. J. 83(1), 491–501 (2002).
[Crossref] [PubMed]

2000 (2)

G. J. L. Wuite, S. B. Smith, M. Young, D. Keller, and C. Bustamante, “Single-molecule studies of the effect of template tension on T7 DNA polymerase activity,” Nature 404(6773), 103–106 (2000).
[Crossref] [PubMed]

J. R. Sellers, “Myosins: a diverse superfamily,” Biochim. Biophys. Acta 1496(1), 3–22 (2000).
[Crossref] [PubMed]

1999 (3)

K. Visscher, M. J. Schnitzer, and S. M. Block, “Single kinesin molecules studied with a molecular force clamp,” Nature 400(6740), 184–189 (1999).
[Crossref] [PubMed]

C. Veigel, L. M. Coluccio, J. D. Jontes, J. C. Sparrow, R. A. Milligan, and J. E. Molloy, “The motor protein myosin-I produces its working stroke in two steps,” Nature 398(6727), 530–533 (1999).
[Crossref] [PubMed]

A. D. Mehta, R. S. Rock, M. Rief, J. A. Spudich, M. S. Mooseker, and R. E. Cheney, “Myosin-V is a processive actin-based motor,” Nature 400(6744), 590–593 (1999).
[Crossref] [PubMed]

1998 (1)

1997 (1)

W. H. Guilford, D. E. Dupuis, G. Kennedy, J. Wu, J. B. Patlak, and D. M. Warshaw, “Smooth muscle and skeletal muscle myosins produce similar unitary forces and displacements in the laser trap,” Biophys. J. 72(3), 1006–1021 (1997).
[Crossref] [PubMed]

1995 (1)

T. Nishizaka, H. Miyata, H. Yoshikawa, S. Ishiwata, and K. Kinosita., “Unbinding force of a single motor molecule of muscle measured using optical tweezers,” Nature 377(6546), 251–254 (1995).
[Crossref] [PubMed]

1994 (1)

J. T. Finer, R. M. Simmons, and J. A. Spudich, “Single myosin molecule mechanics: piconewton forces and nanometre steps,” Nature 368(6467), 113–119 (1994).
[Crossref] [PubMed]

1990 (1)

S. M. Block, L. S. B. Goldstein, and B. J. Schnapp, “Bead movement by single kinesin molecules studied with optical tweezers,” Nature 348(6299), 348–352 (1990).
[Crossref] [PubMed]

1986 (1)

Andreasson, J. O.

Asbury, C. L.

M. J. Lang, C. L. Asbury, J. W. Shaevitz, and S. M. Block, “An Automated Two-Dimensional Optical Force Clamp for Single Molecule Studies,” Biophys. J. 83(1), 491–501 (2002).
[Crossref] [PubMed]

Ashkin, A.

Ataullakhanov, F. I.

V. M. Demidov, S. K. Tripathy, F. I. Ataullakhanov, and E. L. Grishchuk, “Ultrafast Force-Clamp Spectroscopy Reveals “Sliding” Catch-Bond Behavior of the Microtubule-Binding NdC80 Protein,” Biophys. J. 114(3), 382a (2018).
[Crossref]

Bechtold, P.

G. R. B. E. Römer and P. Bechtold, “Electro-optic and Acousto-optic Laser Beam Scanners,” Phys. Procedia 56, 29–39 (2014).
[Crossref]

Beneventi, D.

M. Capitanio, M. Canepari, M. Maffei, D. Beneventi, C. Monico, F. Vanzi, R. Bottinelli, and F. S. Pavone, “Ultrafast force-clamp spectroscopy of single molecules reveals load dependence of myosin working stroke,” Nat. Methods 9(10), 1013–1019 (2012).
[Crossref] [PubMed]

Bjorkholm, J. E.

Block, S. M.

M. T. Valentine, N. R. Guydosh, B. Gutiérrez-Medina, A. N. Fehr, J. O. Andreasson, and S. M. Block, “Precision steering of an optical trap by electro-optic deflection,” Opt. Lett. 33(6), 599–601 (2008).
[Crossref] [PubMed]

M. J. Lang, C. L. Asbury, J. W. Shaevitz, and S. M. Block, “An Automated Two-Dimensional Optical Force Clamp for Single Molecule Studies,” Biophys. J. 83(1), 491–501 (2002).
[Crossref] [PubMed]

K. Visscher, M. J. Schnitzer, and S. M. Block, “Single kinesin molecules studied with a molecular force clamp,” Nature 400(6740), 184–189 (1999).
[Crossref] [PubMed]

S. M. Block, L. S. B. Goldstein, and B. J. Schnapp, “Bead movement by single kinesin molecules studied with optical tweezers,” Nature 348(6299), 348–352 (1990).
[Crossref] [PubMed]

Bottinelli, R.

M. Capitanio, M. Canepari, M. Maffei, D. Beneventi, C. Monico, F. Vanzi, R. Bottinelli, and F. S. Pavone, “Ultrafast force-clamp spectroscopy of single molecules reveals load dependence of myosin working stroke,” Nat. Methods 9(10), 1013–1019 (2012).
[Crossref] [PubMed]

Bustamante, C.

G. J. L. Wuite, S. B. Smith, M. Young, D. Keller, and C. Bustamante, “Single-molecule studies of the effect of template tension on T7 DNA polymerase activity,” Nature 404(6773), 103–106 (2000).
[Crossref] [PubMed]

Canepari, M.

M. Capitanio, M. Canepari, M. Maffei, D. Beneventi, C. Monico, F. Vanzi, R. Bottinelli, and F. S. Pavone, “Ultrafast force-clamp spectroscopy of single molecules reveals load dependence of myosin working stroke,” Nat. Methods 9(10), 1013–1019 (2012).
[Crossref] [PubMed]

Capitanio, M.

A. Tempestini, C. Monico, L. Gardini, F. Vanzi, F. S. Pavone, and M. Capitanio, “Sliding of a single lac repressor protein along DNA is tuned by DNA sequence and molecular switching,” Nucleic Acids Res. 46, gky208 (2018).
[PubMed]

M. Capitanio, M. Canepari, M. Maffei, D. Beneventi, C. Monico, F. Vanzi, R. Bottinelli, and F. S. Pavone, “Ultrafast force-clamp spectroscopy of single molecules reveals load dependence of myosin working stroke,” Nat. Methods 9(10), 1013–1019 (2012).
[Crossref] [PubMed]

Cheney, R. E.

A. D. Mehta, R. S. Rock, M. Rief, J. A. Spudich, M. S. Mooseker, and R. E. Cheney, “Myosin-V is a processive actin-based motor,” Nature 400(6744), 590–593 (1999).
[Crossref] [PubMed]

Chu, S.

Coluccio, L. M.

C. Veigel, L. M. Coluccio, J. D. Jontes, J. C. Sparrow, R. A. Milligan, and J. E. Molloy, “The motor protein myosin-I produces its working stroke in two steps,” Nature 398(6727), 530–533 (1999).
[Crossref] [PubMed]

Demidov, V. M.

V. M. Demidov, S. K. Tripathy, F. I. Ataullakhanov, and E. L. Grishchuk, “Ultrafast Force-Clamp Spectroscopy Reveals “Sliding” Catch-Bond Behavior of the Microtubule-Binding NdC80 Protein,” Biophys. J. 114(3), 382a (2018).
[Crossref]

Dupuis, D. E.

W. H. Guilford, D. E. Dupuis, G. Kennedy, J. Wu, J. B. Patlak, and D. M. Warshaw, “Smooth muscle and skeletal muscle myosins produce similar unitary forces and displacements in the laser trap,” Biophys. J. 72(3), 1006–1021 (1997).
[Crossref] [PubMed]

Dziedzic, J. M.

Fehr, A. N.

Finer, J. T.

J. T. Finer, R. M. Simmons, and J. A. Spudich, “Single myosin molecule mechanics: piconewton forces and nanometre steps,” Nature 368(6467), 113–119 (1994).
[Crossref] [PubMed]

Flyvbjerg, H.

S. F. Tolić-Nørrelykke, E. Schäffer, J. Howard, F. S. Pavone, F. Jülicher, and H. Flyvbjerg, “Calibration of optical tweezers with positional detection in the back focal plane,” Rev. Sci. Instrum. 77(10), 103101 (2006).
[Crossref]

Gardini, L.

A. Tempestini, C. Monico, L. Gardini, F. Vanzi, F. S. Pavone, and M. Capitanio, “Sliding of a single lac repressor protein along DNA is tuned by DNA sequence and molecular switching,” Nucleic Acids Res. 46, gky208 (2018).
[PubMed]

Gittes, F.

Goldman, Y. E.

Y. Takagi, E. E. Homsher, Y. E. Goldman, and H. Shuman, “Force Generation in Single Conventional Actomyosin Complexes under High Dynamic Load,” Biophys. J. 90(4), 1295–1307 (2006).
[Crossref] [PubMed]

Goldstein, L. S. B.

S. M. Block, L. S. B. Goldstein, and B. J. Schnapp, “Bead movement by single kinesin molecules studied with optical tweezers,” Nature 348(6299), 348–352 (1990).
[Crossref] [PubMed]

Greenberg, M. J.

M. J. Greenberg, H. Shuman, and E. M. Ostap, “Inherent Force-Dependent Properties of β-Cardiac Myosin Contribute to the Force-Velocity Relationship of Cardiac Muscle,” Biophys. J. 107(12), L41–L44 (2014).
[Crossref] [PubMed]

Grishchuk, E. L.

V. M. Demidov, S. K. Tripathy, F. I. Ataullakhanov, and E. L. Grishchuk, “Ultrafast Force-Clamp Spectroscopy Reveals “Sliding” Catch-Bond Behavior of the Microtubule-Binding NdC80 Protein,” Biophys. J. 114(3), 382a (2018).
[Crossref]

Guilford, W. H.

W. H. Guilford, D. E. Dupuis, G. Kennedy, J. Wu, J. B. Patlak, and D. M. Warshaw, “Smooth muscle and skeletal muscle myosins produce similar unitary forces and displacements in the laser trap,” Biophys. J. 72(3), 1006–1021 (1997).
[Crossref] [PubMed]

Gutiérrez-Medina, B.

Guydosh, N. R.

Hæggström, E.

A. E. Wallin, H. Ojala, E. Hæggström, and R. Tuma, “Stiffer optical tweezers through real-time feedback control,” Appl. Phys. Lett. 92(22), 224104 (2008).
[Crossref]

Homsher, E. E.

Y. Takagi, E. E. Homsher, Y. E. Goldman, and H. Shuman, “Force Generation in Single Conventional Actomyosin Complexes under High Dynamic Load,” Biophys. J. 90(4), 1295–1307 (2006).
[Crossref] [PubMed]

Howard, J.

S. F. Tolić-Nørrelykke, E. Schäffer, J. Howard, F. S. Pavone, F. Jülicher, and H. Flyvbjerg, “Calibration of optical tweezers with positional detection in the back focal plane,” Rev. Sci. Instrum. 77(10), 103101 (2006).
[Crossref]

Ishiwata, S.

T. Nishizaka, H. Miyata, H. Yoshikawa, S. Ishiwata, and K. Kinosita., “Unbinding force of a single motor molecule of muscle measured using optical tweezers,” Nature 377(6546), 251–254 (1995).
[Crossref] [PubMed]

Jontes, J. D.

C. Veigel, L. M. Coluccio, J. D. Jontes, J. C. Sparrow, R. A. Milligan, and J. E. Molloy, “The motor protein myosin-I produces its working stroke in two steps,” Nature 398(6727), 530–533 (1999).
[Crossref] [PubMed]

Jülicher, F.

S. F. Tolić-Nørrelykke, E. Schäffer, J. Howard, F. S. Pavone, F. Jülicher, and H. Flyvbjerg, “Calibration of optical tweezers with positional detection in the back focal plane,” Rev. Sci. Instrum. 77(10), 103101 (2006).
[Crossref]

Keller, D.

G. J. L. Wuite, S. B. Smith, M. Young, D. Keller, and C. Bustamante, “Single-molecule studies of the effect of template tension on T7 DNA polymerase activity,” Nature 404(6773), 103–106 (2000).
[Crossref] [PubMed]

Kennedy, G.

W. H. Guilford, D. E. Dupuis, G. Kennedy, J. Wu, J. B. Patlak, and D. M. Warshaw, “Smooth muscle and skeletal muscle myosins produce similar unitary forces and displacements in the laser trap,” Biophys. J. 72(3), 1006–1021 (1997).
[Crossref] [PubMed]

Kinosita, K.

T. Nishizaka, H. Miyata, H. Yoshikawa, S. Ishiwata, and K. Kinosita., “Unbinding force of a single motor molecule of muscle measured using optical tweezers,” Nature 377(6546), 251–254 (1995).
[Crossref] [PubMed]

Lang, M. J.

M. J. Lang, C. L. Asbury, J. W. Shaevitz, and S. M. Block, “An Automated Two-Dimensional Optical Force Clamp for Single Molecule Studies,” Biophys. J. 83(1), 491–501 (2002).
[Crossref] [PubMed]

Maffei, M.

M. Capitanio, M. Canepari, M. Maffei, D. Beneventi, C. Monico, F. Vanzi, R. Bottinelli, and F. S. Pavone, “Ultrafast force-clamp spectroscopy of single molecules reveals load dependence of myosin working stroke,” Nat. Methods 9(10), 1013–1019 (2012).
[Crossref] [PubMed]

Mehta, A. D.

A. D. Mehta, R. S. Rock, M. Rief, J. A. Spudich, M. S. Mooseker, and R. E. Cheney, “Myosin-V is a processive actin-based motor,” Nature 400(6744), 590–593 (1999).
[Crossref] [PubMed]

Milligan, R. A.

C. Veigel, L. M. Coluccio, J. D. Jontes, J. C. Sparrow, R. A. Milligan, and J. E. Molloy, “The motor protein myosin-I produces its working stroke in two steps,” Nature 398(6727), 530–533 (1999).
[Crossref] [PubMed]

Miyata, H.

T. Nishizaka, H. Miyata, H. Yoshikawa, S. Ishiwata, and K. Kinosita., “Unbinding force of a single motor molecule of muscle measured using optical tweezers,” Nature 377(6546), 251–254 (1995).
[Crossref] [PubMed]

Molloy, J. E.

C. Veigel, L. M. Coluccio, J. D. Jontes, J. C. Sparrow, R. A. Milligan, and J. E. Molloy, “The motor protein myosin-I produces its working stroke in two steps,” Nature 398(6727), 530–533 (1999).
[Crossref] [PubMed]

Monico, C.

A. Tempestini, C. Monico, L. Gardini, F. Vanzi, F. S. Pavone, and M. Capitanio, “Sliding of a single lac repressor protein along DNA is tuned by DNA sequence and molecular switching,” Nucleic Acids Res. 46, gky208 (2018).
[PubMed]

M. Capitanio, M. Canepari, M. Maffei, D. Beneventi, C. Monico, F. Vanzi, R. Bottinelli, and F. S. Pavone, “Ultrafast force-clamp spectroscopy of single molecules reveals load dependence of myosin working stroke,” Nat. Methods 9(10), 1013–1019 (2012).
[Crossref] [PubMed]

Mooseker, M. S.

A. D. Mehta, R. S. Rock, M. Rief, J. A. Spudich, M. S. Mooseker, and R. E. Cheney, “Myosin-V is a processive actin-based motor,” Nature 400(6744), 590–593 (1999).
[Crossref] [PubMed]

Muretta, J. M.

J. A. Rohde, D. D. Thomas, and J. M. Muretta, “Heart failure drug changes the mechanoenzymology of the cardiac myosin powerstroke,” Proc. Natl. Acad. Sci. U.S.A. 114(10), E1796–E1804 (2017).
[Crossref] [PubMed]

J. M. Muretta, K. J. Petersen, and D. D. Thomas, “Direct real-time detection of the actin-activated power stroke within the myosin catalytic domain,” Proc. Natl. Acad. Sci. U.S.A. 110(18), 7211–7216 (2013).
[Crossref] [PubMed]

Nishizaka, T.

T. Nishizaka, H. Miyata, H. Yoshikawa, S. Ishiwata, and K. Kinosita., “Unbinding force of a single motor molecule of muscle measured using optical tweezers,” Nature 377(6546), 251–254 (1995).
[Crossref] [PubMed]

Ojala, H.

A. E. Wallin, H. Ojala, E. Hæggström, and R. Tuma, “Stiffer optical tweezers through real-time feedback control,” Appl. Phys. Lett. 92(22), 224104 (2008).
[Crossref]

Ostap, E. M.

M. J. Greenberg, H. Shuman, and E. M. Ostap, “Inherent Force-Dependent Properties of β-Cardiac Myosin Contribute to the Force-Velocity Relationship of Cardiac Muscle,” Biophys. J. 107(12), L41–L44 (2014).
[Crossref] [PubMed]

Patlak, J. B.

W. H. Guilford, D. E. Dupuis, G. Kennedy, J. Wu, J. B. Patlak, and D. M. Warshaw, “Smooth muscle and skeletal muscle myosins produce similar unitary forces and displacements in the laser trap,” Biophys. J. 72(3), 1006–1021 (1997).
[Crossref] [PubMed]

Pavone, F. S.

A. Tempestini, C. Monico, L. Gardini, F. Vanzi, F. S. Pavone, and M. Capitanio, “Sliding of a single lac repressor protein along DNA is tuned by DNA sequence and molecular switching,” Nucleic Acids Res. 46, gky208 (2018).
[PubMed]

M. Capitanio, M. Canepari, M. Maffei, D. Beneventi, C. Monico, F. Vanzi, R. Bottinelli, and F. S. Pavone, “Ultrafast force-clamp spectroscopy of single molecules reveals load dependence of myosin working stroke,” Nat. Methods 9(10), 1013–1019 (2012).
[Crossref] [PubMed]

S. F. Tolić-Nørrelykke, E. Schäffer, J. Howard, F. S. Pavone, F. Jülicher, and H. Flyvbjerg, “Calibration of optical tweezers with positional detection in the back focal plane,” Rev. Sci. Instrum. 77(10), 103101 (2006).
[Crossref]

Petersen, K. J.

J. M. Muretta, K. J. Petersen, and D. D. Thomas, “Direct real-time detection of the actin-activated power stroke within the myosin catalytic domain,” Proc. Natl. Acad. Sci. U.S.A. 110(18), 7211–7216 (2013).
[Crossref] [PubMed]

Rief, M.

A. D. Mehta, R. S. Rock, M. Rief, J. A. Spudich, M. S. Mooseker, and R. E. Cheney, “Myosin-V is a processive actin-based motor,” Nature 400(6744), 590–593 (1999).
[Crossref] [PubMed]

Rock, R. S.

A. D. Mehta, R. S. Rock, M. Rief, J. A. Spudich, M. S. Mooseker, and R. E. Cheney, “Myosin-V is a processive actin-based motor,” Nature 400(6744), 590–593 (1999).
[Crossref] [PubMed]

Rohde, J. A.

J. A. Rohde, D. D. Thomas, and J. M. Muretta, “Heart failure drug changes the mechanoenzymology of the cardiac myosin powerstroke,” Proc. Natl. Acad. Sci. U.S.A. 114(10), E1796–E1804 (2017).
[Crossref] [PubMed]

Römer, G. R. B. E.

G. R. B. E. Römer and P. Bechtold, “Electro-optic and Acousto-optic Laser Beam Scanners,” Phys. Procedia 56, 29–39 (2014).
[Crossref]

Schäffer, E.

S. F. Tolić-Nørrelykke, E. Schäffer, J. Howard, F. S. Pavone, F. Jülicher, and H. Flyvbjerg, “Calibration of optical tweezers with positional detection in the back focal plane,” Rev. Sci. Instrum. 77(10), 103101 (2006).
[Crossref]

Schmidt, C. F.

Schnapp, B. J.

S. M. Block, L. S. B. Goldstein, and B. J. Schnapp, “Bead movement by single kinesin molecules studied with optical tweezers,” Nature 348(6299), 348–352 (1990).
[Crossref] [PubMed]

Schnitzer, M. J.

K. Visscher, M. J. Schnitzer, and S. M. Block, “Single kinesin molecules studied with a molecular force clamp,” Nature 400(6740), 184–189 (1999).
[Crossref] [PubMed]

Sellers, J. R.

J. R. Sellers, “Myosins: a diverse superfamily,” Biochim. Biophys. Acta 1496(1), 3–22 (2000).
[Crossref] [PubMed]

Shaevitz, J. W.

M. J. Lang, C. L. Asbury, J. W. Shaevitz, and S. M. Block, “An Automated Two-Dimensional Optical Force Clamp for Single Molecule Studies,” Biophys. J. 83(1), 491–501 (2002).
[Crossref] [PubMed]

Shuman, H.

M. J. Greenberg, H. Shuman, and E. M. Ostap, “Inherent Force-Dependent Properties of β-Cardiac Myosin Contribute to the Force-Velocity Relationship of Cardiac Muscle,” Biophys. J. 107(12), L41–L44 (2014).
[Crossref] [PubMed]

Y. Takagi, E. E. Homsher, Y. E. Goldman, and H. Shuman, “Force Generation in Single Conventional Actomyosin Complexes under High Dynamic Load,” Biophys. J. 90(4), 1295–1307 (2006).
[Crossref] [PubMed]

Simmons, R. M.

J. T. Finer, R. M. Simmons, and J. A. Spudich, “Single myosin molecule mechanics: piconewton forces and nanometre steps,” Nature 368(6467), 113–119 (1994).
[Crossref] [PubMed]

Smith, S. B.

G. J. L. Wuite, S. B. Smith, M. Young, D. Keller, and C. Bustamante, “Single-molecule studies of the effect of template tension on T7 DNA polymerase activity,” Nature 404(6773), 103–106 (2000).
[Crossref] [PubMed]

Sparrow, J. C.

C. Veigel, L. M. Coluccio, J. D. Jontes, J. C. Sparrow, R. A. Milligan, and J. E. Molloy, “The motor protein myosin-I produces its working stroke in two steps,” Nature 398(6727), 530–533 (1999).
[Crossref] [PubMed]

Spudich, J. A.

A. D. Mehta, R. S. Rock, M. Rief, J. A. Spudich, M. S. Mooseker, and R. E. Cheney, “Myosin-V is a processive actin-based motor,” Nature 400(6744), 590–593 (1999).
[Crossref] [PubMed]

J. T. Finer, R. M. Simmons, and J. A. Spudich, “Single myosin molecule mechanics: piconewton forces and nanometre steps,” Nature 368(6467), 113–119 (1994).
[Crossref] [PubMed]

Takagi, Y.

Y. Takagi, E. E. Homsher, Y. E. Goldman, and H. Shuman, “Force Generation in Single Conventional Actomyosin Complexes under High Dynamic Load,” Biophys. J. 90(4), 1295–1307 (2006).
[Crossref] [PubMed]

Tempestini, A.

A. Tempestini, C. Monico, L. Gardini, F. Vanzi, F. S. Pavone, and M. Capitanio, “Sliding of a single lac repressor protein along DNA is tuned by DNA sequence and molecular switching,” Nucleic Acids Res. 46, gky208 (2018).
[PubMed]

Thomas, D. D.

J. A. Rohde, D. D. Thomas, and J. M. Muretta, “Heart failure drug changes the mechanoenzymology of the cardiac myosin powerstroke,” Proc. Natl. Acad. Sci. U.S.A. 114(10), E1796–E1804 (2017).
[Crossref] [PubMed]

J. M. Muretta, K. J. Petersen, and D. D. Thomas, “Direct real-time detection of the actin-activated power stroke within the myosin catalytic domain,” Proc. Natl. Acad. Sci. U.S.A. 110(18), 7211–7216 (2013).
[Crossref] [PubMed]

Tolic-Nørrelykke, S. F.

S. F. Tolić-Nørrelykke, E. Schäffer, J. Howard, F. S. Pavone, F. Jülicher, and H. Flyvbjerg, “Calibration of optical tweezers with positional detection in the back focal plane,” Rev. Sci. Instrum. 77(10), 103101 (2006).
[Crossref]

Tripathy, S. K.

V. M. Demidov, S. K. Tripathy, F. I. Ataullakhanov, and E. L. Grishchuk, “Ultrafast Force-Clamp Spectroscopy Reveals “Sliding” Catch-Bond Behavior of the Microtubule-Binding NdC80 Protein,” Biophys. J. 114(3), 382a (2018).
[Crossref]

Tuma, R.

A. E. Wallin, H. Ojala, E. Hæggström, and R. Tuma, “Stiffer optical tweezers through real-time feedback control,” Appl. Phys. Lett. 92(22), 224104 (2008).
[Crossref]

Valentine, M. T.

Vanzi, F.

A. Tempestini, C. Monico, L. Gardini, F. Vanzi, F. S. Pavone, and M. Capitanio, “Sliding of a single lac repressor protein along DNA is tuned by DNA sequence and molecular switching,” Nucleic Acids Res. 46, gky208 (2018).
[PubMed]

M. Capitanio, M. Canepari, M. Maffei, D. Beneventi, C. Monico, F. Vanzi, R. Bottinelli, and F. S. Pavone, “Ultrafast force-clamp spectroscopy of single molecules reveals load dependence of myosin working stroke,” Nat. Methods 9(10), 1013–1019 (2012).
[Crossref] [PubMed]

Veigel, C.

C. Veigel, L. M. Coluccio, J. D. Jontes, J. C. Sparrow, R. A. Milligan, and J. E. Molloy, “The motor protein myosin-I produces its working stroke in two steps,” Nature 398(6727), 530–533 (1999).
[Crossref] [PubMed]

Visscher, K.

K. Visscher, M. J. Schnitzer, and S. M. Block, “Single kinesin molecules studied with a molecular force clamp,” Nature 400(6740), 184–189 (1999).
[Crossref] [PubMed]

Wallin, A. E.

A. E. Wallin, H. Ojala, E. Hæggström, and R. Tuma, “Stiffer optical tweezers through real-time feedback control,” Appl. Phys. Lett. 92(22), 224104 (2008).
[Crossref]

Warshaw, D. M.

W. H. Guilford, D. E. Dupuis, G. Kennedy, J. Wu, J. B. Patlak, and D. M. Warshaw, “Smooth muscle and skeletal muscle myosins produce similar unitary forces and displacements in the laser trap,” Biophys. J. 72(3), 1006–1021 (1997).
[Crossref] [PubMed]

Wu, J.

W. H. Guilford, D. E. Dupuis, G. Kennedy, J. Wu, J. B. Patlak, and D. M. Warshaw, “Smooth muscle and skeletal muscle myosins produce similar unitary forces and displacements in the laser trap,” Biophys. J. 72(3), 1006–1021 (1997).
[Crossref] [PubMed]

Wuite, G. J. L.

G. J. L. Wuite, S. B. Smith, M. Young, D. Keller, and C. Bustamante, “Single-molecule studies of the effect of template tension on T7 DNA polymerase activity,” Nature 404(6773), 103–106 (2000).
[Crossref] [PubMed]

Yoshikawa, H.

T. Nishizaka, H. Miyata, H. Yoshikawa, S. Ishiwata, and K. Kinosita., “Unbinding force of a single motor molecule of muscle measured using optical tweezers,” Nature 377(6546), 251–254 (1995).
[Crossref] [PubMed]

Young, M.

G. J. L. Wuite, S. B. Smith, M. Young, D. Keller, and C. Bustamante, “Single-molecule studies of the effect of template tension on T7 DNA polymerase activity,” Nature 404(6773), 103–106 (2000).
[Crossref] [PubMed]

Appl. Phys. Lett. (1)

A. E. Wallin, H. Ojala, E. Hæggström, and R. Tuma, “Stiffer optical tweezers through real-time feedback control,” Appl. Phys. Lett. 92(22), 224104 (2008).
[Crossref]

Biochim. Biophys. Acta (1)

J. R. Sellers, “Myosins: a diverse superfamily,” Biochim. Biophys. Acta 1496(1), 3–22 (2000).
[Crossref] [PubMed]

Biophys. J. (5)

M. J. Greenberg, H. Shuman, and E. M. Ostap, “Inherent Force-Dependent Properties of β-Cardiac Myosin Contribute to the Force-Velocity Relationship of Cardiac Muscle,” Biophys. J. 107(12), L41–L44 (2014).
[Crossref] [PubMed]

W. H. Guilford, D. E. Dupuis, G. Kennedy, J. Wu, J. B. Patlak, and D. M. Warshaw, “Smooth muscle and skeletal muscle myosins produce similar unitary forces and displacements in the laser trap,” Biophys. J. 72(3), 1006–1021 (1997).
[Crossref] [PubMed]

Y. Takagi, E. E. Homsher, Y. E. Goldman, and H. Shuman, “Force Generation in Single Conventional Actomyosin Complexes under High Dynamic Load,” Biophys. J. 90(4), 1295–1307 (2006).
[Crossref] [PubMed]

V. M. Demidov, S. K. Tripathy, F. I. Ataullakhanov, and E. L. Grishchuk, “Ultrafast Force-Clamp Spectroscopy Reveals “Sliding” Catch-Bond Behavior of the Microtubule-Binding NdC80 Protein,” Biophys. J. 114(3), 382a (2018).
[Crossref]

M. J. Lang, C. L. Asbury, J. W. Shaevitz, and S. M. Block, “An Automated Two-Dimensional Optical Force Clamp for Single Molecule Studies,” Biophys. J. 83(1), 491–501 (2002).
[Crossref] [PubMed]

Nat. Methods (1)

M. Capitanio, M. Canepari, M. Maffei, D. Beneventi, C. Monico, F. Vanzi, R. Bottinelli, and F. S. Pavone, “Ultrafast force-clamp spectroscopy of single molecules reveals load dependence of myosin working stroke,” Nat. Methods 9(10), 1013–1019 (2012).
[Crossref] [PubMed]

Nature (7)

S. M. Block, L. S. B. Goldstein, and B. J. Schnapp, “Bead movement by single kinesin molecules studied with optical tweezers,” Nature 348(6299), 348–352 (1990).
[Crossref] [PubMed]

A. D. Mehta, R. S. Rock, M. Rief, J. A. Spudich, M. S. Mooseker, and R. E. Cheney, “Myosin-V is a processive actin-based motor,” Nature 400(6744), 590–593 (1999).
[Crossref] [PubMed]

T. Nishizaka, H. Miyata, H. Yoshikawa, S. Ishiwata, and K. Kinosita., “Unbinding force of a single motor molecule of muscle measured using optical tweezers,” Nature 377(6546), 251–254 (1995).
[Crossref] [PubMed]

G. J. L. Wuite, S. B. Smith, M. Young, D. Keller, and C. Bustamante, “Single-molecule studies of the effect of template tension on T7 DNA polymerase activity,” Nature 404(6773), 103–106 (2000).
[Crossref] [PubMed]

J. T. Finer, R. M. Simmons, and J. A. Spudich, “Single myosin molecule mechanics: piconewton forces and nanometre steps,” Nature 368(6467), 113–119 (1994).
[Crossref] [PubMed]

C. Veigel, L. M. Coluccio, J. D. Jontes, J. C. Sparrow, R. A. Milligan, and J. E. Molloy, “The motor protein myosin-I produces its working stroke in two steps,” Nature 398(6727), 530–533 (1999).
[Crossref] [PubMed]

K. Visscher, M. J. Schnitzer, and S. M. Block, “Single kinesin molecules studied with a molecular force clamp,” Nature 400(6740), 184–189 (1999).
[Crossref] [PubMed]

Nucleic Acids Res. (1)

A. Tempestini, C. Monico, L. Gardini, F. Vanzi, F. S. Pavone, and M. Capitanio, “Sliding of a single lac repressor protein along DNA is tuned by DNA sequence and molecular switching,” Nucleic Acids Res. 46, gky208 (2018).
[PubMed]

Opt. Lett. (3)

Phys. Procedia (1)

G. R. B. E. Römer and P. Bechtold, “Electro-optic and Acousto-optic Laser Beam Scanners,” Phys. Procedia 56, 29–39 (2014).
[Crossref]

Proc. Natl. Acad. Sci. U.S.A. (2)

J. M. Muretta, K. J. Petersen, and D. D. Thomas, “Direct real-time detection of the actin-activated power stroke within the myosin catalytic domain,” Proc. Natl. Acad. Sci. U.S.A. 110(18), 7211–7216 (2013).
[Crossref] [PubMed]

J. A. Rohde, D. D. Thomas, and J. M. Muretta, “Heart failure drug changes the mechanoenzymology of the cardiac myosin powerstroke,” Proc. Natl. Acad. Sci. U.S.A. 114(10), E1796–E1804 (2017).
[Crossref] [PubMed]

Rev. Sci. Instrum. (1)

S. F. Tolić-Nørrelykke, E. Schäffer, J. Howard, F. S. Pavone, F. Jülicher, and H. Flyvbjerg, “Calibration of optical tweezers with positional detection in the back focal plane,” Rev. Sci. Instrum. 77(10), 103101 (2006).
[Crossref]

Other (3)

Conoptics Inc, “Optical Trapping Deflection Systems,” http://www.conoptics.com/optical-trapping-deflection-systems/ .

M. Bugiel, A. Jannasch, and E. Schäffer, “Implementation and Tuning of an Optical Tweezers Force-Clamp Feedback System,” in Optical Tweezers, Methods in Molecular Biology (Humana Press, New York, NY, 2017), pp. 109–136.

Goutzoulis, Design and Fabrication of Acousto-Optic Devices (CRC Press, 1994).

Supplementary Material (1)

NameDescription
» Visualization 1       Video sequence of the infrared light scattered from an acousto-optical deflector during scanning.

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Figures (7)

Fig. 1
Fig. 1 Illustration of the sequence of events in the ultra-fast force clamp method. Changes between each frame are highlighted in yellow. A) An actin dumbbell is held under pretension load by two optical traps which can be independently controlled via force-feedback loops and beam steering devices (either AODs or EODs). B). The setpoint of the feedback loop for one bead (right) is increased by F, which causes a force to be exerted to the right, resulting in the motion of the dumbbell at a constant velocity (v) which creates hydrodynamic drag on the dumbbell that matches the applied force, F. The feedback loops work to maintain a constant force on both beads during the dumbbell’s motion. C) After a set excursion distance, the force setpoints are changed for both beads, with the applied force, F, now being applied to the left bead in the opposite direction. This results in motion of the dumbbell in the opposite direction. D)This cycle repeats until the myosin interacts with the actin filament, at which point the force is quickly transferred from hydrodynamic drag to the myosin molecule and the dumbbell’s motion stops within ~30-50 microseconds. This allows precise detection of the attachment time and the ability to study myosin under set loads from the beginning of its interaction with actin.
Fig. 2
Fig. 2 A) Example of artifactual ~20 nm jumps in the dumbbell position during an interaction between myosin and the actin filament while the force-clamp is engaged using AOD beam steering. Jumps are marked by red arrows. B) A control experiment replacing myosin with alpha-actinin, which interacts with actin but is not expected to cause displacements. Similar jumps of 15 nm are marked (red arrows). C) Another control experiment placed the trapping laser over a pedestal bead stuck firmly to the surface and engaged the force-clamp feedback. Although the time scale of the feedback loop was different here, artifactual ~10 nm jumps of the trap position were observed.
Fig. 3
Fig. 3 A) Example of variations in the force signal observed with the AOD beam steering system as a function of beam position. The y-axis shows the differential voltage from the QPD as the trap position was scanned in the chamber without any trapped bead. Similar variations were seen when the bead was present but were visually masked by Brownian motions. The variations are shown without (red) and with (blue) intensity-maintaining feedback. The two signals overlay nearly perfectly and are displayed with an offset for clarity. The two x-axis scales below panel B apply both to panels A and B. B) The total intensity of the light reaching the QPD also varies with a similar periodicity. Using an independent feedback loop to maintain a constant total QPD illumination (B, blue), did not eliminate the variations in force signals. C) The standard deviations of the fluctuations over a 100 nm window were calculated over the entire 25 μm deflection range of the AOD. Some positions (corresponding to particular RF frequencies) exhibited much larger variations in the recorded force signal than the average. The y-axis scale in C corresponds approximately to pN using typical experimental calibrations.
Fig. 4
Fig. 4 A) Snapshot from video of a 1064 nm wavelength beam at the face of the AOD crystal (Visualization 1). The applied RF signal was swept over a range of 100 kHz in a 10 second period, corresponding to about 75 nm of displacement at the microscope stage. The video rate is 10 frames per second. The intensity of each frame has been normalized. Two regions of interest (ROIs) were selected, shown in red (ROI 1) and green (ROI 2). B) The original mean frame intensity (blue) from the video of panel A shows an approximate periodicity of 25 kHz, corresponding to 20 nm at the sample. The intensity-normalized video (orange) has a constant mean intensity, as expected. This normalized video was used for analysis in panels C and D. C) The mean intensity in each ROI in the normalized video shows pseudo-periodic fluctuations in its localized intensity with a similar period (25 kHz). The fluctuations in the different regions vary in amplitude and phase. D) The signal that would be created from projecting the recorded images onto either a Quadrant Photodiode (QPD, blue) or a lateral effect photodiode (LEP, red) were calculated. The force signal varied for both types of detectors with similar periodicity but with somewhat different secondary characteristics.
Fig. 5
Fig. 5 A) Simulated error signals for a trapped bead undergoing Brownian motion. The total measured error signal as a function of trap position (red) includes the Hookean (linear) trap force (yellow) and the imposed variations from the AOD (blue) modeled as a sinusoidal curve. Due to the influence of the AOD force variations, there are two possible trap positions (−7 nm and + 7 nm) where the force will be stabilized at the set point (zero error signal, purple). B) Simulated trap positions for the potential in A using parameters similar to our experiments. The trap position quickly jumps between the values where the total measured force is equal to the set point (horizontal dashed lines show intercepts of red and purple curves from A. C) A reduction in the amplitude of the variations and doubling of their spacing changes the profile of the measured error response (red), effectively reducing the loop gain. D) Simulated trap positions from the profiles in C show that large jumps are no longer observed, but the small AOD variations introduce added noise. E) A comparison of the simulated trap positions with the low levels of non-linearity shown in Panel C (blue histogram) compared with simulated positions without non-linearities (pink histogram). F) Simulated trap positions under feedback when only the trap’s potential is present and non-linearities are absent.
Fig. 6
Fig. 6 A) Schematic of the optical trap setup including EODs. Dashed blue lines indicate conjugate planes. L7 is necessary to create a conjugate plane at Picomotor Mirror 1 (PM1) to properly control the position of EOD B’s beam relative to EOD A’s beam. A similar lens is included after EOD A to maintain the optical characteristics between the two beam paths. HWP A (Half Wave Plate) is necessary to rotate the polarization of the incoming light to horizontal as required for deflection. A pair of lenses in front of each EOD (L2-L4, and L3-L5) acts to reduce the beam diameter during transit through the EOD crystals. The layout used with the AOD was similar to that shown, however without the lenses described above and slightly different positions of half waveplates and other lenses. PBS1 allows the total intensity of both traps to be simultaneous controlled by diverting energy into a beam block (black box). PBS: Polarizing Beam Splitter, M: Mirror, L: Lens, HV Amp: High voltage amplifier.
Fig. 7
Fig. 7 A) Characterization of the deflection of the EODs as a function of trap position (green) shows a uniform detected force signal on the QPD. The corresponding signal using AODs from Fig. 3 is shown offset at the same scale. B) An enlarged view of the EOD data from Panel A shows that there are no detectable “wiggles” in the deflection of the beam by the EOD. C) The actin dumbbell’s position is shown for the beginning of a single interaction between cardiac myosin and actin using the EOD-based force-clamp system. Red dashed lines guide the eye to the dumbbell’s motions. The dumbbell is traveling at a constant velocity under feedback before it quickly stops at t = 1 ms. There is one clear displacement of ~10 nm at 2 ms and no other large fluctuations. A similar figure for the AOD-based system is shown in Fig. 2A without the initial motion of the filament at a constant velocity.

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