在松弛的兔腰大肌粗肌丝上对肌球蛋白横桥螺旋进行直接可视化观察。

Direct visualization of the myosin crossbridge helices on relaxed rabbit psoas thick filaments.

作者信息

Ip W, Heuser J

出版信息

J Mol Biol. 1983 Nov 25;171(1):105-9. doi: 10.1016/s0022-2836(83)80317-9.

Abstract

Thick filaments in relaxed, quick-frozen and freeze-etched psoas myofibrils display a prominent helical pattern of projections repeating at 43 +/- 1 nm. These helices are right-handed, and measurement of the pitch angle indicates that the thick filaments are three-stranded. Each half-turn of a helix is composed of three to five projections, 11 to 12 nm in diameter. These projections probably represent individual myosin crossbridges. This is the first direct visualization of the crossbridge helices in vertebrate striated muscle filaments whose three-dimensional structure is preserved without chemical fixation.

摘要

在松弛、快速冷冻和冷冻蚀刻的腰大肌肌原纤维中，粗肌丝呈现出突出的螺旋状突起模式，重复间距为43±1纳米。这些螺旋是右旋的，螺距角的测量表明粗肌丝是三股的。螺旋的每半圈由三到五个直径为11至12纳米的突起组成。这些突起可能代表单个肌球蛋白横桥。这是首次在未经化学固定而保留三维结构的脊椎动物横纹肌细丝中直接观察到横桥螺旋。