扇贝肌球蛋白s1在动力冲程前状态下分辨率为2.6埃的晶体结构：头部的灵活性与功能

Crystal structure of scallop Myosin s1 in the pre-power stroke state to 2.6 a resolution: flexibility and function in the head.

作者信息

Gourinath S, Himmel Daniel M, Brown Jerry H, Reshetnikova Ludmilla, Szent-Györgyi Andrew G, Cohen Carolyn

机构信息

Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA.

出版信息

Structure. 2003 Dec;11(12):1621-7. doi: 10.1016/j.str.2003.10.013.

DOI:10.1016/j.str.2003.10.013

PMID:14656445

Abstract

We have extended the X-ray structure determination of the complete scallop myosin head in the pre-power stroke state to 2.6 A resolution, allowing an atomic comparison of the three major (weak actin binding) states of various myosins. We can now account for conformational differences observed in crystal structures in the so-called "pliant region" at the motor domain-lever arm junction between scallop and vertebrate smooth muscle myosins. A hinge, which may contribute to the compliance of the myosin crossbridge, has also been identified for the first time within the regulatory light-chain domain of the lever arm. Analysis of temperature factors of key joints of the motor domain, especially the SH1 helix, provides crystallographic evidence for the existence of the "internally uncoupled" state in diverse isoforms. The agreement between structural and solution studies reinforces the view that the unwinding of the SH1 helix is a part of the cross-bridge cycle in many myosins.

摘要

我们已将处于动力冲程前状态的完整扇贝肌球蛋白头部的X射线结构测定分辨率提高到2.6埃，从而能够对各种肌球蛋白的三种主要（弱肌动蛋白结合）状态进行原子层面的比较。现在我们可以解释在扇贝和脊椎动物平滑肌肌球蛋白的运动结构域 - 杠杆臂连接处的所谓“柔顺区域”中晶体结构所观察到的构象差异。在杠杆臂的调节轻链结构域内首次鉴定出一个铰链，它可能有助于肌球蛋白横桥的柔韧性。对运动结构域关键关节，特别是SH1螺旋的温度因子分析，为不同同工型中“内部解偶联”状态的存在提供了晶体学证据。结构研究与溶液研究之间的一致性强化了这样一种观点，即SH1螺旋的展开是许多肌球蛋白横桥循环的一部分。