Structural Insight into Unique Cardiac Myosin-binding Protein-C Motif
Structural Insight into Unique Cardiac Myosin-binding Protein-C Motif
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独特的心肌肌球蛋白结合蛋白 C 基序的结构洞察
DOI：
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发表时间：
2012
影响因子：
4.8
通讯作者：
P. Rosevear
中科院分区：
文献类型：
--
作者：
J. Howarth;Srinivasa R. Ramisetti;K. Nolan;S. Sadayappan;P. Rosevear
背景：心肌肌球蛋白结合蛋白-C 是调节肌节结构和功能所必需的肌节组装蛋白。结果：cMyBP-C 基序由两个子域组成，一个很大程度上无序的 N 端部分和一个更加有序的 C 端子域。结论：C端亚结构域能够形成三螺旋束。意义：三螺旋束可能为肌动蛋白结合提供平台。心肌肌球蛋白结合蛋白-C 的独特肌球蛋白结合基序（m 结构域）的结构作用仍不清楚。从功能上讲，m 结构域被认为直接与肌球蛋白相互作用，而 m 结构域的磷酸化已被证明可以调节肌球蛋白和肌动蛋白之间的相互作用。在这里，我们利用 NMR 来分析溶液中 m 域的结构和动力学。我们的研究表明，m 结构域由两个子结构域组成，一个很大程度上无序的 N 端部分（包含三个已知的磷酸化位点）和一个更有序且折叠的 C 端部分。化学位移分析、dNN(i, i + 1) NOE 和 15N{1H} 异核 NOE 值表明，C 末端子结构域（残基 315-351）由跨越残基 317-322、327-335 和 341-348 的三个明确定义的螺旋构成。使用 CS-Rosetta 使用完整的 13Cα、13Cβ、13C'、15N、1Hα 和 1HN 化学位移计算三级结构。选择了 20 个可接受的结构的集合来代表表现出新颖的三螺旋束折叠的 C 端子结构域。发现第三个螺旋的溶剂暴露面含有基本肌动蛋白结合基序 LK(R/K)XK。相反，N 端子域的 15N{1H} 异核 NOE 值与构象更灵活的区域一致。二级结构倾向得分表明跨越残基 265-268 和 293-295 的两个瞬时螺旋。弱连续 dNN(i, i + 1) NOE 支持两个瞬时螺旋的存在。因此，m 结构域由灵活且很大程度上无序的 N 端子结构域和具有三螺旋束折叠的 C 端子结构域组成，可能提供肌动蛋白结合平台。
Background: Cardiac myosin-binding protein-C is a sarcomeric assembly protein necessary for the regulation of sarcomere structure and function. Results: The cMyBP-C motif is composed of two subdomains, a largely disordered N-terminal portion and a more ordered C-terminal subdomain. Conclusion: The C-terminal subdomain is capable of forming a three-helix bundle. Significance: The three-helix bundle may provide a platform for actin binding. The structural role of the unique myosin-binding motif (m-domain) of cardiac myosin-binding protein-C remains unclear. Functionally, the m-domain is thought to directly interact with myosin, whereas phosphorylation of the m-domain has been shown to modulate interactions between myosin and actin. Here we utilized NMR to analyze the structure and dynamics of the m-domain in solution. Our studies reveal that the m-domain is composed of two subdomains, a largely disordered N-terminal portion containing three known phosphorylation sites and a more ordered and folded C-terminal portion. Chemical shift analyses, dNN(i, i + 1) NOEs, and 15N{1H} heteronuclear NOE values show that the C-terminal subdomain (residues 315–351) is structured with three well defined helices spanning residues 317–322, 327–335, and 341–348. The tertiary structure was calculated with CS-Rosetta using complete 13Cα, 13Cβ, 13C′, 15N, 1Hα, and 1HN chemical shifts. An ensemble of 20 acceptable structures was selected to represent the C-terminal subdomain that exhibits a novel three-helix bundle fold. The solvent-exposed face of the third helix was found to contain the basic actin-binding motif LK(R/K)XK. In contrast, 15N{1H} heteronuclear NOE values for the N-terminal subdomain are consistent with a more conformationally flexible region. Secondary structure propensity scores indicate two transient helices spanning residues 265–268 and 293–295. The presence of both transient helices is supported by weak sequential dNN(i, i + 1) NOEs. Thus, the m-domain consists of an N-terminal subdomain that is flexible and largely disordered and a C-terminal subdomain having a three-helix bundle fold, potentially providing an actin-binding platform.
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影响因子：
20.1
作者：
Harris SP;Lyons RG;Bezold KL
通讯作者：
Bezold KL
骨骼肌中肌球蛋白结合蛋白 C 和 H（MyBP-C、MyBP-H）的 A 带定位域的鉴定。
影响因子：
4
作者：
Gilbert,R;Cohen,JA;Pardo,S;Basu,A;Fischman,DA
通讯作者：
Fischman,DA
影响因子：
3.4
作者：
Karsai, Arpad;Kellermayer, Miklos S. Z.;Harris, Samantha P.
通讯作者：
Harris, Samantha P.
影响因子：
3
作者：
Kensler, Robert W.;Shaffer, Justin F.;Harris, Samantha P.
通讯作者：
Harris, Samantha P.
影响因子：
5
作者：
Copeland, O'Neal;Sadayappan, Sakthivel;Marston, Steven B.
通讯作者：
Marston, Steven B.