Cheung P, Reisler E
Department of Chemistry and Biochemistry, University of California, Los Angeles 90024.
Biochem Biophys Res Commun. 1992 Dec 15;189(2):1143-9. doi: 10.1016/0006-291x(92)92323-p.
A synthetic peptide corresponding to a sequence 632-642 (S632-642) on the myosin subfragment 1 (S-1) heavy chain and spanning the 50/20 kDa junction of S-1 binds to actin in the presence and absence of S-1. The binding of 1.0 mole of peptide per actin causes almost complete inhibition of actomyosin ATPase activity and only partial inhibition of S-1 binding to actin. The binding of S632-642 to the N-terminal segment of actin is supported by competitive carbodiimide cross-linking of S-1 and S632-642 to actin and the catalytic properties of cross-linked acto-S-1 and actin-peptide complexes. These results show that the sequence 632-642 on S-1 is an autonomous binding site for actin and confirm the catalytic importance of its interactions with the N-terminal segment of actin.
一种与肌球蛋白亚片段1（S-1）重链上632-642序列（S632-642）相对应且跨越S-1的50/20 kDa连接点的合成肽，在有或没有S-1的情况下都能与肌动蛋白结合。每摩尔肌动蛋白结合1.0摩尔肽几乎完全抑制肌动球蛋白ATP酶活性，而对S-1与肌动蛋白的结合仅产生部分抑制。S632-642与肌动蛋白N端片段的结合得到S-1和S632-642与肌动蛋白的竞争性碳二亚胺交联以及交联的肌动蛋白-S-1和肌动蛋白-肽复合物催化特性的支持。这些结果表明，S-1上的632-642序列是肌动蛋白的一个自主结合位点，并证实了其与肌动蛋白N端片段相互作用的催化重要性。
