SPECIFIC PHOSPHORYLATION AT SERINE-283 OF ALPHA-TROPOMYOSIN FROM FROM SKELETAL AND RABBIT SKELETAL AND CARDIAC-MUSCLE
SPECIFIC PHOSPHORYLATION AT SERINE-283 OF ALPHA-TROPOMYOSIN FROM FROM SKELETAL AND RABBIT SKELETAL AND CARDIAC-MUSCLE
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DOI：
10.1073/pnas.75.8.3588
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发表时间：
1978-01-01
影响因子：
11.1
通讯作者：
BARANY, M
中科院分区：
文献类型：
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作者：
MAK, A;SMILLIE, LB;BARANY, M
从注射了[32 P]正磷酸盐的青蛙的腿肌中提取的原肌球蛋白被分级分离成2种组分，α和β。和β，在CM-纤维素柱上。放射性仅与α相关。成分单个磷酸化位点位于蛙α的丝氨酸-283（COOH末端的倒数第二个）。原肌球蛋白从两种兔骨骼α和β中以低产率回收相同的磷酸化肽。和心肌原肌球蛋白。共价键合的磷酸盐在α中的存在。原肌球蛋白和它在β中的缺失。31 P NMR [核磁共振]光谱表明骨骼肌的成分。蛙和兔原肌球蛋白磷酸化位点周围的氨基酸序列是相同的。因为该序列与蛋白质中任何其它已知的磷酸化位点都不相似，这表明存在可以区分α和β的特异性激酶或磷酸酶。和β原肌球蛋白在针对α的头到尾重叠提出的模型中，在原肌球蛋白分子中，一个O-磷酸丝氨酸-283残基可以在重叠区的一侧与赖氨酸-6形成盐键，另一侧与赖氨酸-12形成盐键。这将预测磷酸化和非磷酸化α的聚合物的稳定性的差异。α的和α。β的原肌球蛋白的二聚体。
Tropomyosin, extracted from the leg muscle of frogs that had been injected with [32P]orthophosphate, was fractionated into 2 components, .alpha. and .beta., on a CM-cellulose column. Radioactivity was associated only with the .alpha. component. A single phosphorylation site was located at serine-283 (penultimate at the COOH-terminal end) of the frog .alpha. tropomyosin. The same phosphorylated peptide was recovered in low yields from both rabbit skeletal .alpha. and cardiac tropomyosin. The presence of covalently bound phosphate in .alpha. tropomyosin and its absence in the .beta. component of skeletal muscle was suggested by 31P NMR [nuclear magnetic resonance] spectroscopy. The amino acid sequences around the phosphorylation sites of frog and rabbit tropomyosin are identical. Because this sequence is not similar to any other known phosphorylation site in proteins, this indicates the existence of either a specific kinase or a phosphatase that can distinguish between .alpha. and .beta. tropomyosins. In a model proposed for the head-to-tail overlap of .alpha. tropomyosin molecules, one O-phosphoserine-283 residue could form a salt linkage with lysine-6 on one side of the overlap region and another with lysine-12 on the other side. This would predict a difference in the stability of polymers of phosphorylated and nonphosphorylated .alpha..alpha. and .alpha..beta. dimers of tropmyosin.