Structure of the tropomyosin overlap complex from chicken smooth muscle: insight into the diversity of N-terminal recognition.
Structure of the tropomyosin overlap complex from chicken smooth muscle: insight into the diversity of N-terminal recognition.
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DOI：
10.1021/bi100349a
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发表时间：
2010-06-15
期刊：
影响因子：
2.9
通讯作者：
Rayment, Ivan
中科院分区：
文献类型：
--
作者：
Frye, Jeremiah;Klenchin, Vadim A.;Rayment, Ivan
原肌球蛋白是一种典型的α-螺旋卷曲螺旋，聚合形成丝状大分子组装体，位于F-肌动蛋白表面。相邻分子上的C-末端和N-末端片段之间的相互作用被称为重叠区域。我们在这里报告两个鸡平滑肌原肌球蛋白重叠复合物的X射线结构。一种新的方法被用来稳定的C-末端和N-末端片段。来自人DNA连接酶结合蛋白XRCC 4和噬菌体φ29支架蛋白Gp 7的球状结构域分别与原肌球蛋白的37和28个C-末端氨基酸残基融合，而原肌球蛋白的N-末端29个氨基酸与微管结合蛋白EB 1的C-末端螺旋束融合。与N-末端EB 1融合体复合的XRCC 4和Gp 7融合蛋白的结构在重叠区包含非常相似的螺旋束，其包含约15个残基。C-末端卷曲螺旋打开以允许形成螺旋束，其通过疏水相互作用稳定。这些结构类似于在大鼠骨骼重叠复合物的NMR结构中观察到的结构[格林菲尔德等人，等人（2006）J. Mol. 364，80-96]。平滑肌原肌球蛋白的N-和C-末端卷曲螺旋之间的相互作用显示出显著的曲率，这两种结构之间略有不同，并意味着重叠复合物的灵活性，至少在溶液中。这可能是一个重要的属性，使原肌球蛋白组装周围的肌动蛋白丝。这些结构为N-乙酰化在天然原肌球蛋白组装中的作用提供了分子解释。
Tropomyosin is a stereotypical α-helical coiled-coil that polymerizes to form a filamentous macromolecular assembly that lies on the surface of F-actin. The interaction between the C-terminal and N-terminal segments on adjacent molecules is known as the overlap region. We report here two X-ray structures of the chicken smooth muscle tropomyosin overlap complex. A novel approach was used to stabilize the C-terminal and N-terminal fragments. Globular domains from both the human DNA ligase binding protein XRCC4 and bacteriophage φ29 scaffolding protein Gp7 were fused to 37 and 28 C-terminal amino acid residues of tropomyosin, respectively, whereas the N-terminal 29 amino acids of tropomyosin were fused to the C-terminal helix bundle of the microtubule binding protein EB1. The structures of both the XRCC4 and Gp7 fusion proteins complexed with the N-terminal EB1 fusion contain a very similar helix bundle in the overlap region which encompasses ~15 residues. The C-terminal coiled-coiled coil opens to allow formation of the helix bundle, which is stabilized by hydrophobic interactions. These structures are similar to that observed in the NMR structure of the rat skeletal overlap complex [Greenfield et al., (2006) J. Mol. Biol. 364, 80–96]. The interactions between the N- and C-terminal coiled-coils of smooth muscle tropomyosin show significant curvature, which differs somewhat between the two structures and implies flexibility in the overlap complex, at least in solution. This is likely an important attribute that allows tropomyosin to assemble around the actin filaments. These structures provide a molecular explanation for the role of N-acetylation in the assembly of native tropomyosin.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
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作者：
Greenfield, NJ;Huang, YJ;Hitchcock-DeGregori, SE
通讯作者：
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影响因子：
2.9
作者：
Greenfield, NJ;Swapna, GVT;Hitchcock-DeGregori, SE
通讯作者：
Hitchcock-DeGregori, SE
影响因子：
2.9
作者：
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通讯作者：
Kim, PS
DOI：
10.1073/pnas.0509269102
发表时间：
2005-12-27
影响因子：
11.1
作者：
Brown, JH;Zhou, ZC;Cohen, C
通讯作者：
Cohen, C