TROPOMYOSIN LENGTH AND 2-STRANDED F-ACTIN FLEXIBILITY IN THE THIN FILAMENT

被引:7
|
作者
CENSULLO, R [1 ]
CHEUNG, HC [1 ]
机构
[1] UNIV ALABAMA, DEPT BIOCHEM, UNIV STN, BIRMINGHAM, AL 35294 USA
关键词
ACTIN; TROPOMYOSIN; THIN FILAMENT; MUSCLE CONTRACTION; REGULATION;
D O I
10.1006/jmbi.1994.1677
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
In muscle thin filaments, each tropomyosin molecule is considered to be a rope-like structure that winds along the filament in contact with seven consecutive actin monomers on the same strand of the two-stranded actin helix. Taking into account the head-to-tail overlap of the tropomyosin molecule, the effective length of this ''rope'' is about 405 Angstrom, which is believed to be conserved. Tropomyosin appears to be neither extensible nor compressible in its axial direction, although it may possess much flexibility in the transverse direction. During the ''maximally on'' state, characterized by the presence of Ca2+ and the strong binding between actin and myosin subfragment 1, the following conditions are thought to occur: the motion and associated flexibility of tropomyosin are reduced; the actin filament flexibility increases; a maximum number of equivalent tropomyosin binding sites on actin are concurrently saturated; and the tropomyosin molecule maintains an average thin filament radius of 38 to 40 Angstrom. Under these potentiated conditions, the length of tropomyosin can be used to determine the limits on the underlying ''cumulative angular disorder'' of the actin filament with which it interacts. Our calculations show that only a small amount (similar to 1 to 3 degrees) of this type of actin monomer rotational disorder is possible at this stage of the contractile cycle, unless the length of the tropomyosin molecule is increased substantially between the head-to-tail joints. However, if the dominant type of F-actin rotational flexibility is between two relatively rigid actin strands (the lateral slipping/rotational offset model), all of the above actin-tropomyosin interactions can be completely and easily accommodated. We also discuss the implications of an interdomain hinge in G-actin and the possibility that there may be fewer than seven equivalent sites on actin that are saturated by tropomyosin concurrent.
引用
收藏
页码:520 / 529
页数:10
相关论文
共 50 条
  • [1] 2-STRANDED F-ACTIN AND TROPOMYOSIN BINDING
    CENSULLO, R
    BIOPHYSICAL JOURNAL, 1994, 66 (02) : A194 - A194
  • [2] A ROTATIONAL OFFSET MODEL FOR 2-STRANDED F-ACTIN
    CENSULLO, R
    CHEUNG, HC
    JOURNAL OF STRUCTURAL BIOLOGY, 1993, 110 (01) : 75 - 83
  • [3] DYNAMIC PROPERTY OF F-ACTIN AND THIN FILAMENT
    OOSAWA, F
    FUJIME, S
    ISHIWATA, S
    MIHASHI, K
    COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY, 1973, 37 : 277 - 285
  • [4] Rotational motion of tropomyosin on the F-actin filament titrated with Sl.
    Chandy, IK
    Ludescher, RD
    BIOPHYSICAL JOURNAL, 1996, 70 (02) : SUP93 - SUP93
  • [5] Filament flexibility enhances power transduction of F-actin bundles
    Perilli, Alessia
    Pierleoni, Carlo
    Ryckaert, Jean-Paul
    JOURNAL OF CHEMICAL PHYSICS, 2019, 150 (18):
  • [6] THE FLEXIBILITY OF F-ACTIN
    OOSAWA, F
    BIOPHYSICAL CHEMISTRY, 1980, 11 (3-4) : 443 - 446
  • [7] Severing of F-actin by cofilin: effects of pH and filament flexibility.
    Pavlov, DA
    Muhlrad, A
    Cooper, JA
    Wear, M
    Reisler, E
    BIOPHYSICAL JOURNAL, 2004, 86 (01) : 360A - 361A
  • [8] Structure of the F-actin–tropomyosin complex
    Julian von der Ecken
    Mirco Müller
    William Lehman
    Dietmar J. Manstein
    Pawel A. Penczek
    Stefan Raunser
    Nature, 2015, 519 : 114 - 117
  • [9] STUDIES ON INTERACTION OF F-ACTIN WITH TROPOMYOSIN
    DRABIKOWSKI, W
    NOWAK, E
    EUROPEAN JOURNAL OF BIOCHEMISTRY, 1968, 5 (03): : 376 - +
  • [10] EFFECT OF MYOSIN ON DYNAMIC PROPERTY OF F-ACTIN AND THIN FILAMENT
    OOSAWA, F
    BIORHEOLOGY, 1975, 12 (02) : 96 - 96