Direct measurement of the torsional rigidity of single actin filaments

Ryohei Yasuda, Hidetake Miyata, Kazuhiko Kinosita

Research output: Contribution to journalArticle

113 Citations (Scopus)

Abstract

Flexural and torsional rigidities of actin filaments are important factors in cell motility and muscle contraction, where actin filaments serve as mechanical elements. The flexural rigidity has already been determined by directly observing the bending of individual filaments under a microscope, but measurement of the torsional rigidity has been relatively scarce and indirect, because torsion of an actin filament is difficult to visualize. This paper shows that the torsional rigidity can be measured directly by visualizing the torsional Brownian motion of a single actin filament with a novel methodology based on an optical trapping technique. Actin filaments (F-actin) were prepared by polymerizing actin monomers binding Ca2+ ion or Mg2+ ion at the high affinity site. The torsional rigidity of F-Ca2+-actin ((8.5 (± 1.3)) x 10-26 N m2) was about three times as large as that of F-Mg2+-actin ((2.8 (± 0.3)) x 10-26 N m2), whereas the flexural rigidity ((6.0 (± 0.2)) x 10-26 N m2) was almost independent of the kind of the bound cation. The dynamic structure of F-actin is regulated by the bound metal in an anisotropic manner. The torsional rigidities above, whether of F-Ca2+-actin or F-Mg2+-actin, are one to two orders of magnitude greater than previous experimental estimates.

Original languageEnglish
Pages (from-to)227-236
Number of pages10
JournalJournal of Molecular Biology
Volume263
Issue number2
DOIs
Publication statusPublished - 1996 Oct 25
Externally publishedYes

Fingerprint

Actin Cytoskeleton
Actins
Optical Tweezers
Ions
Muscle Contraction
Cell Movement
Cations
Metals

Keywords

  • Divalent cation
  • Flexural rigidity
  • Fluorescence
  • Optical microscope
  • Optical tweezers

ASJC Scopus subject areas

  • Virology

Cite this

Direct measurement of the torsional rigidity of single actin filaments. / Yasuda, Ryohei; Miyata, Hidetake; Kinosita, Kazuhiko.

In: Journal of Molecular Biology, Vol. 263, No. 2, 25.10.1996, p. 227-236.

Research output: Contribution to journalArticle

Yasuda, Ryohei ; Miyata, Hidetake ; Kinosita, Kazuhiko. / Direct measurement of the torsional rigidity of single actin filaments. In: Journal of Molecular Biology. 1996 ; Vol. 263, No. 2. pp. 227-236.
@article{b9203a7123bb4f47a4b4a1428baf7677,
title = "Direct measurement of the torsional rigidity of single actin filaments",
abstract = "Flexural and torsional rigidities of actin filaments are important factors in cell motility and muscle contraction, where actin filaments serve as mechanical elements. The flexural rigidity has already been determined by directly observing the bending of individual filaments under a microscope, but measurement of the torsional rigidity has been relatively scarce and indirect, because torsion of an actin filament is difficult to visualize. This paper shows that the torsional rigidity can be measured directly by visualizing the torsional Brownian motion of a single actin filament with a novel methodology based on an optical trapping technique. Actin filaments (F-actin) were prepared by polymerizing actin monomers binding Ca2+ ion or Mg2+ ion at the high affinity site. The torsional rigidity of F-Ca2+-actin ((8.5 (± 1.3)) x 10-26 N m2) was about three times as large as that of F-Mg2+-actin ((2.8 (± 0.3)) x 10-26 N m2), whereas the flexural rigidity ((6.0 (± 0.2)) x 10-26 N m2) was almost independent of the kind of the bound cation. The dynamic structure of F-actin is regulated by the bound metal in an anisotropic manner. The torsional rigidities above, whether of F-Ca2+-actin or F-Mg2+-actin, are one to two orders of magnitude greater than previous experimental estimates.",
keywords = "Divalent cation, Flexural rigidity, Fluorescence, Optical microscope, Optical tweezers",
author = "Ryohei Yasuda and Hidetake Miyata and Kazuhiko Kinosita",
year = "1996",
month = "10",
day = "25",
doi = "10.1006/jmbi.1996.0571",
language = "English",
volume = "263",
pages = "227--236",
journal = "Journal of Molecular Biology",
issn = "0022-2836",
publisher = "Academic Press Inc.",
number = "2",

}

TY - JOUR

T1 - Direct measurement of the torsional rigidity of single actin filaments

AU - Yasuda, Ryohei

AU - Miyata, Hidetake

AU - Kinosita, Kazuhiko

PY - 1996/10/25

Y1 - 1996/10/25

N2 - Flexural and torsional rigidities of actin filaments are important factors in cell motility and muscle contraction, where actin filaments serve as mechanical elements. The flexural rigidity has already been determined by directly observing the bending of individual filaments under a microscope, but measurement of the torsional rigidity has been relatively scarce and indirect, because torsion of an actin filament is difficult to visualize. This paper shows that the torsional rigidity can be measured directly by visualizing the torsional Brownian motion of a single actin filament with a novel methodology based on an optical trapping technique. Actin filaments (F-actin) were prepared by polymerizing actin monomers binding Ca2+ ion or Mg2+ ion at the high affinity site. The torsional rigidity of F-Ca2+-actin ((8.5 (± 1.3)) x 10-26 N m2) was about three times as large as that of F-Mg2+-actin ((2.8 (± 0.3)) x 10-26 N m2), whereas the flexural rigidity ((6.0 (± 0.2)) x 10-26 N m2) was almost independent of the kind of the bound cation. The dynamic structure of F-actin is regulated by the bound metal in an anisotropic manner. The torsional rigidities above, whether of F-Ca2+-actin or F-Mg2+-actin, are one to two orders of magnitude greater than previous experimental estimates.

AB - Flexural and torsional rigidities of actin filaments are important factors in cell motility and muscle contraction, where actin filaments serve as mechanical elements. The flexural rigidity has already been determined by directly observing the bending of individual filaments under a microscope, but measurement of the torsional rigidity has been relatively scarce and indirect, because torsion of an actin filament is difficult to visualize. This paper shows that the torsional rigidity can be measured directly by visualizing the torsional Brownian motion of a single actin filament with a novel methodology based on an optical trapping technique. Actin filaments (F-actin) were prepared by polymerizing actin monomers binding Ca2+ ion or Mg2+ ion at the high affinity site. The torsional rigidity of F-Ca2+-actin ((8.5 (± 1.3)) x 10-26 N m2) was about three times as large as that of F-Mg2+-actin ((2.8 (± 0.3)) x 10-26 N m2), whereas the flexural rigidity ((6.0 (± 0.2)) x 10-26 N m2) was almost independent of the kind of the bound cation. The dynamic structure of F-actin is regulated by the bound metal in an anisotropic manner. The torsional rigidities above, whether of F-Ca2+-actin or F-Mg2+-actin, are one to two orders of magnitude greater than previous experimental estimates.

KW - Divalent cation

KW - Flexural rigidity

KW - Fluorescence

KW - Optical microscope

KW - Optical tweezers

UR - http://www.scopus.com/inward/record.url?scp=0030601791&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030601791&partnerID=8YFLogxK

U2 - 10.1006/jmbi.1996.0571

DO - 10.1006/jmbi.1996.0571

M3 - Article

VL - 263

SP - 227

EP - 236

JO - Journal of Molecular Biology

JF - Journal of Molecular Biology

SN - 0022-2836

IS - 2

ER -