Torsional motion of eosin-labeled F-actin as detected in the time-resolved anisotropy decay of the probe in the sub-millisecond time range

Hideyuki Yoshimura, Takuhiro Nishio, Koshin Mihashi, Kazuhiko Kinosita, Akira Ikegami

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

The internal motion of F-actin in the time range from 10-6 to 10-3 second has been explored by measuring the transient absorption anisotropy of eosin-labeled F-actin using laser flash photolysis. The transient absorption anisotropy of eosin-F-actin at 20 °C has a component that decays in the submicrosecond time scale to an anisotropy of about 0.3. This anisotropy then decays with a relaxation time of about 450 μs to a residual anisotropy of about 0.1 after 2 ms. When the concentration of eosin-F-actin was varied in the range from 7 to 28 μm, the transient absorption anisotropy curves obtained were almost indistinguishable from each other. These results show that the anisotropy decay arises from internal motion of eosin-F-actin. Analysis of the transient absorption anisotropy curves indicates that the internal motion detected by the decay in anisotropy is primarily a twisting of actin protomers in the F-actin helix; bending of the actin filament makes a minor contribution only to the measured decay. The torsional rigidity calculated from the transient absorption anisotropy is 0.2 × 10-17 dyn cm2 at 20 °C, which is about an order of magnitude smaller than the flexural rigidity determined from previous studies. Thus, we conclude that F-actin is more flexible in twisting than in bending. The calculated root-mean-square fluctuation of the torsional angle between adjacent actin protomers in the actin helix is about 4 ° at 20 °C. We also found that the torsional rigidity is approximately constant in the temperature range from 5 to ~35 °C, and that the binding of phalloidin does not appreciably affect the torsional motion of F-actin.

Original languageEnglish
Pages (from-to)453-467
Number of pages15
JournalJournal of Molecular Biology
Volume179
Issue number3
DOIs
Publication statusPublished - 1984 Nov 5
Externally publishedYes

Fingerprint

Anisotropy
Eosine Yellowish-(YS)
Actins
Protein Subunits
Phalloidine
Photolysis
Actin Cytoskeleton
Lasers

ASJC Scopus subject areas

  • Virology

Cite this

Torsional motion of eosin-labeled F-actin as detected in the time-resolved anisotropy decay of the probe in the sub-millisecond time range. / Yoshimura, Hideyuki; Nishio, Takuhiro; Mihashi, Koshin; Kinosita, Kazuhiko; Ikegami, Akira.

In: Journal of Molecular Biology, Vol. 179, No. 3, 05.11.1984, p. 453-467.

Research output: Contribution to journalArticle

Yoshimura, Hideyuki ; Nishio, Takuhiro ; Mihashi, Koshin ; Kinosita, Kazuhiko ; Ikegami, Akira. / Torsional motion of eosin-labeled F-actin as detected in the time-resolved anisotropy decay of the probe in the sub-millisecond time range. In: Journal of Molecular Biology. 1984 ; Vol. 179, No. 3. pp. 453-467.
@article{5c7d7284a4cd44d78bbdd475551f205f,
title = "Torsional motion of eosin-labeled F-actin as detected in the time-resolved anisotropy decay of the probe in the sub-millisecond time range",
abstract = "The internal motion of F-actin in the time range from 10-6 to 10-3 second has been explored by measuring the transient absorption anisotropy of eosin-labeled F-actin using laser flash photolysis. The transient absorption anisotropy of eosin-F-actin at 20 °C has a component that decays in the submicrosecond time scale to an anisotropy of about 0.3. This anisotropy then decays with a relaxation time of about 450 μs to a residual anisotropy of about 0.1 after 2 ms. When the concentration of eosin-F-actin was varied in the range from 7 to 28 μm, the transient absorption anisotropy curves obtained were almost indistinguishable from each other. These results show that the anisotropy decay arises from internal motion of eosin-F-actin. Analysis of the transient absorption anisotropy curves indicates that the internal motion detected by the decay in anisotropy is primarily a twisting of actin protomers in the F-actin helix; bending of the actin filament makes a minor contribution only to the measured decay. The torsional rigidity calculated from the transient absorption anisotropy is 0.2 × 10-17 dyn cm2 at 20 °C, which is about an order of magnitude smaller than the flexural rigidity determined from previous studies. Thus, we conclude that F-actin is more flexible in twisting than in bending. The calculated root-mean-square fluctuation of the torsional angle between adjacent actin protomers in the actin helix is about 4 ° at 20 °C. We also found that the torsional rigidity is approximately constant in the temperature range from 5 to ~35 °C, and that the binding of phalloidin does not appreciably affect the torsional motion of F-actin.",
author = "Hideyuki Yoshimura and Takuhiro Nishio and Koshin Mihashi and Kazuhiko Kinosita and Akira Ikegami",
year = "1984",
month = "11",
day = "5",
doi = "10.1016/0022-2836(84)90075-5",
language = "English",
volume = "179",
pages = "453--467",
journal = "Journal of Molecular Biology",
issn = "0022-2836",
publisher = "Academic Press Inc.",
number = "3",

}

TY - JOUR

T1 - Torsional motion of eosin-labeled F-actin as detected in the time-resolved anisotropy decay of the probe in the sub-millisecond time range

AU - Yoshimura, Hideyuki

AU - Nishio, Takuhiro

AU - Mihashi, Koshin

AU - Kinosita, Kazuhiko

AU - Ikegami, Akira

PY - 1984/11/5

Y1 - 1984/11/5

N2 - The internal motion of F-actin in the time range from 10-6 to 10-3 second has been explored by measuring the transient absorption anisotropy of eosin-labeled F-actin using laser flash photolysis. The transient absorption anisotropy of eosin-F-actin at 20 °C has a component that decays in the submicrosecond time scale to an anisotropy of about 0.3. This anisotropy then decays with a relaxation time of about 450 μs to a residual anisotropy of about 0.1 after 2 ms. When the concentration of eosin-F-actin was varied in the range from 7 to 28 μm, the transient absorption anisotropy curves obtained were almost indistinguishable from each other. These results show that the anisotropy decay arises from internal motion of eosin-F-actin. Analysis of the transient absorption anisotropy curves indicates that the internal motion detected by the decay in anisotropy is primarily a twisting of actin protomers in the F-actin helix; bending of the actin filament makes a minor contribution only to the measured decay. The torsional rigidity calculated from the transient absorption anisotropy is 0.2 × 10-17 dyn cm2 at 20 °C, which is about an order of magnitude smaller than the flexural rigidity determined from previous studies. Thus, we conclude that F-actin is more flexible in twisting than in bending. The calculated root-mean-square fluctuation of the torsional angle between adjacent actin protomers in the actin helix is about 4 ° at 20 °C. We also found that the torsional rigidity is approximately constant in the temperature range from 5 to ~35 °C, and that the binding of phalloidin does not appreciably affect the torsional motion of F-actin.

AB - The internal motion of F-actin in the time range from 10-6 to 10-3 second has been explored by measuring the transient absorption anisotropy of eosin-labeled F-actin using laser flash photolysis. The transient absorption anisotropy of eosin-F-actin at 20 °C has a component that decays in the submicrosecond time scale to an anisotropy of about 0.3. This anisotropy then decays with a relaxation time of about 450 μs to a residual anisotropy of about 0.1 after 2 ms. When the concentration of eosin-F-actin was varied in the range from 7 to 28 μm, the transient absorption anisotropy curves obtained were almost indistinguishable from each other. These results show that the anisotropy decay arises from internal motion of eosin-F-actin. Analysis of the transient absorption anisotropy curves indicates that the internal motion detected by the decay in anisotropy is primarily a twisting of actin protomers in the F-actin helix; bending of the actin filament makes a minor contribution only to the measured decay. The torsional rigidity calculated from the transient absorption anisotropy is 0.2 × 10-17 dyn cm2 at 20 °C, which is about an order of magnitude smaller than the flexural rigidity determined from previous studies. Thus, we conclude that F-actin is more flexible in twisting than in bending. The calculated root-mean-square fluctuation of the torsional angle between adjacent actin protomers in the actin helix is about 4 ° at 20 °C. We also found that the torsional rigidity is approximately constant in the temperature range from 5 to ~35 °C, and that the binding of phalloidin does not appreciably affect the torsional motion of F-actin.

UR - http://www.scopus.com/inward/record.url?scp=0021692991&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0021692991&partnerID=8YFLogxK

U2 - 10.1016/0022-2836(84)90075-5

DO - 10.1016/0022-2836(84)90075-5

M3 - Article

C2 - 6210369

AN - SCOPUS:0021692991

VL - 179

SP - 453

EP - 467

JO - Journal of Molecular Biology

JF - Journal of Molecular Biology

SN - 0022-2836

IS - 3

ER -