Multiple conformations of PEVK proteins detected by single-molecule techniques
Multiple conformations of PEVK proteins detected by single-molecule techniques
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DOI：
10.1073/pnas.191189098
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发表时间：
2001-09-11
影响因子：
11.1
通讯作者：
Fernandez, JM
中科院分区：
文献类型：
--
作者：
Li, HB;Oberhauser, AF;Fernandez, JM
肌弹性的一个重要组成部分是肌球蛋白的PEVK区域，因这些氨基酸的优势而得名。然而，PEVK区域，类似于其他弹性蛋白，被认为是形成随机线圈，因此其结构不能用标准技术确定。在这里，我们结合单分子电子显微镜和原子力显微镜来检查人类心脏titin PEVK区域的构象。与简单的随机线圈相比，我们发现心脏PEVK显示出广泛的弹性构象，端到端距离从9到24 nm不等，持续长度从0.4到2.5 nm不等。单个PEVK分子通过许多拉伸-松弛循环保持其独特的弹性构象，这与这些PEVK构象不能通过力相互转换的观点一致。心脏PEVK的多种弹性构象可能是由不同程度的脯氨酸异构化引起的。这里展示的单分子技术可能有助于阐明其他缺乏明确结构的蛋白质的构象。
An important component of muscle elasticity is the PEVK region of titin, so named because of the preponderance of these amino acids. However, the PEVK region, similar to other elastomeric proteins, is thought to form a random coil and therefore its structure cannot be determined by standard techniques. Here we combine single-molecule electron microscopy and atomic force microscopy to examine the conformations of the human cardiac titin PEVK region. In contrast to a simple random coil, we have found that cardiac PEVK shows a wide range of elastic conformations with end-to-end distances ranging from 9 to 24 nm and persistence lengths from 0.4 to 2.5 nm. Individual PEVK molecules retained their distinctive elastic conformations through many stretch-relaxation cycles, consistent with the view that these PEVK conformers cannot be interconverted by force. The multiple elastic conformations of cardiac PEVK may result from varying degrees of proline isomerization. The single-molecule techniques demonstrated here may help elucidate the conformation of other proteins that lack a well-defined structure.