Lehman William, Craig Roger
Department of Physiology and Biophysics, Boston University School of Medicine, 715 Albany Street, Boston, MA 02118, USA.
Adv Exp Med Biol. 2008;644:95-109. doi: 10.1007/978-0-387-85766-4_8.
Contraction in all muscles must be precisely regulated and requisite control systems must be able to adjust to changes in physiological and myopathic stimuli. In this chapter, we outline the structural evidence for a steric mechanism that governs muscle activity. The mechanism involves calcium and myosin induced changes in the position of tropomyosin along actin-based thin filaments. This process either blocks or uncovers myosin crossbridge binding sites on actin and consequently regulates crossbridge cycling on thin filaments, the sliding of thin and thick filaments and muscle shortening and force production.
所有肌肉的收缩都必须得到精确调节，必要的控制系统必须能够适应生理和肌病刺激的变化。在本章中，我们概述了一种控制肌肉活动的空间机制的结构证据。该机制涉及钙和肌球蛋白诱导的原肌球蛋白沿肌动蛋白细肌丝位置的变化。这个过程要么阻断要么暴露肌动蛋白上的肌球蛋白横桥结合位点，从而调节细肌丝上的横桥循环、细肌丝和粗肌丝的滑动以及肌肉收缩和力量产生。
