Complete unfolding of the titin molecule under external force
Complete unfolding of the titin molecule under external force
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DOI：
10.1006/jsbi.1998.3988
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发表时间：
1998-01-01
影响因子：
3
通讯作者：
Granzier, HL
中科院分区：
文献类型：
--
作者：
Kellermayer, MSZ;Smith, SB;Granzier, HL
肌联蛋白（也称为连接蛋白）是一种巨大的丝状蛋白，跨越脊椎动物肌肉肌节的Z线和M线之间的距离。一些早期的研究表明肌联蛋白在维持肌节结构完整性和产生肌肉的被动力方面起着重要作用。肌联蛋白的弹性特性的特点是在最近的单分子力学作品，描述了分子作为一个熵弹簧，其中部分展开可能会发生在高的力在拉伸和重折叠在低的力在释放过程中。在目前的工作中，使用激光镊子以高于400 pN的力拉伸肌联蛋白分子。高外力导致分子完全机械展开，其特征在于在高力下力滞后消失。肌联蛋白完全变性后重新折叠，因为在低力下的滞后现象在随后的拉伸释放循环中再次出现。在整个展开发生的广泛的力范围内表明，在肌联蛋白的各种球状域需要不同的展开力，由于其展开的活化能的差异。(C)北京：科学出版社.
Titin (also known as connectin) is a giant filamentous protein that spans the distance between the Z- and M-lines of the vertebrate muscle sarcomere. Several earlier studies have implicated titin as playing a fundamental role in maintaining sarcomeric structural integrity and generating the passive force of muscle. The elastic properties of titin were characterized in recent single-molecule mechanical works that described the molecule as an entropic spring in which partial unfolding may take place at high forces during stretch and refolding at low forces during release. In the present work titin molecules were stretched using a laser tweezer with forces above 400 pN. The high external forces resulted in complete mechanical unfolding off the molecule, characterized by the disappearance of force hysteresis at high forces. Titin refolded following complete denaturation, as the hysteresis at low forces reappeared in subsequent stretch-release cycles. The broad force range throughout which unfolding occurred indicates that the various globular domains in titin require different unfolding forces due to differences in the activation energies for their unfolding. (C) 1998 Academic Press.