Molecular polarity in tropomyosin troponin T co-crystals
Molecular polarity in tropomyosin troponin T co-crystals
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DOI：
10.1016/s0006-3495(97)78206-7
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发表时间：
1997-10-01
影响因子：
3.4
通讯作者：
Cohen, C
中科院分区：
文献类型：
--
作者：
CabralLilly, D;Tobacman, LS;Cohen, C
通过所谓的双金刚石共晶的电子显微镜揭示了肌钙蛋白 T 和原肌球蛋白的结构和相互作用的新特征。这些共晶体是使用兔 α(2) 原肌球蛋白与来自骨骼肌或心肌的肌钙蛋白 T 复合形成的，其氨基末端区域长度不同，以及细菌表达的骨骼肌肌钙蛋白 T 片段（缺少氨基末端区域），有 190 个残基。共晶图像的差异使我们能够确定投影晶格中肌钙蛋白 T 亚基和原肌球蛋白的极性。此外，与它们的序列一致，牛心肌肌钙蛋白 T 同工型的氨基末端区域似乎比兔骨骼肌肌钙蛋白 T 同工型的氨基末端区域更长，并且在头尾细丝接头处跨越更多的原肌球蛋白氨基末端。相对于电子束倾斜的晶体图像也揭示了该晶格中原肌球蛋白丝的超螺旋。基于这些结果，构建了双金刚石晶格的三维模型。
New features of the structure and interactions of troponin T and tropomyosin have been revealed by electron microscopy of so-called double-diamond co-crystals. These co-crystals were formed using rabbit alpha(2) tropomyosin complexed with troponin T from either skeletal or cardiac muscle, which have different lengths in the amino-terminal region, as well as a bacterially expressed skeletal muscle troponin T fragment of 190 residues that lacks the amino-terminal region. Differences in the images of the co-crystals have allowed us to establish the polarities of both the troponin T subunit and tropomyosin in the projected lattice. Moreover, in agreement with their sequences, the amino-terminal region of a bovine cardiac muscle troponin T isoform appears to be longer than that from the rabbit skeletal muscle troponin T isoform and to span more of the amino terminus of tropomyosin at the head-to-tail filament joints. Images of crystals tilted relative to the electron beam also reveal the supercoiling of the tropomyosin filaments in this lattice. Based on these results, a three-dimensional model of the double-diamond lattice has been constructed.