A comparison of the amino acid sequences of rabbit skeletal muscle alpha- and beta-tropomyosins.
A comparison of the amino acid sequences of rabbit skeletal muscle alpha- and beta-tropomyosins.
复制标题
兔骨骼肌α-和β-原肌球蛋白的氨基酸序列的比较。
DOI：
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发表时间：
1980
影响因子：
4.8
通讯作者：
G. Stewart
中科院分区：
文献类型：
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作者：
A. Mak;L. Smillie;G. Stewart
兔骨骼β-原肌球蛋白的完整氨基酸序列的解析表明，它具有相同数量的残基（284），每链的α组分从相同的来源。通过在序列中的11个位置检测到异质性，表明存在一种以上形式的β-原肌球蛋白。主要形式与次要形式的比例估计约为10：1。在主要α和β形式的39个氨基酸残基差异中，大多数涉及化学相似的残基，其中只有两个残基导致β形式上的净电荷更负（Ser-229变为谷氨酸，His-276变为天冬酰胺）。这些替换并不显着影响重复的七肽模式的非极性和极性残基在原肌球蛋白，也没有14倍的周期性酸性和外部非极性残基牵连其结合到F-肌动蛋白。在蛋白质的COOH-末端的一半中的较大数目的取代反映在与α组分相比时β-原肌球蛋白序列的平滑α-螺旋参数的差异中。这些差异可能与β-原肌球蛋白与肌钙蛋白的结合亲和力较低有关。
Elucidation of the complete amino acid sequence of rabbit skeletal beta-tropomyosin has shown that it has the same number of residues (284) per chain as the alpha component from the same source. The presence of more than one form of beta-tropomyosin was indicated by the detection of heterogeneity at 11 positions in the sequence. The ratio of the major form to the minor form(s) was estimated to be about 10:1. Of the 39 amino acid residue differences in the major alpha and beta forms, most involve chemically similar residues with only two leading to a more negative net charge on the beta form (Ser-229 to glutamic acid and His-276 to asparagine). These replacements do not significantly affect the repeating heptapeptide pattern of nonpolar and polar residues in tropomyosin nor the 14-fold periodicity of acidic and outer nonpolar residues implicated in its binding to F-actin. The larger number of substitutions in the COOH-terminal half of the protein is reflected in differences in the smoothed alpha-helix parameters of the beta-tropomyosin sequence when compared with that of the alpha component. These differences may be related to a lower binding affinity of beta-tropomyosin to troponin.