人心肌肌球蛋白轻链1与重链和肌动蛋白的结合

在测得中国人心肌肌球蛋白轻链 1cDNA的核苷酸序列 ,并获得一株单克隆抗体 (HCMLC1 8)的基础上 ,用PCR方法 ,以中国人心肌肌球蛋白轻链 1的cDNA为模板 ,分别获得中国人心肌肌球蛋白轻链 1的各为 98个氨基酸的N端和C端片段cDNA的克隆并进行了表达。同时进行了其表达产物和大鼠心肌肌球蛋白重链和人心肌肌动蛋白以及单克隆抗体结合的研究 ,发现三者均和轻链 1的N端相结合 ,结合位点各不相同。这些结合位点可能均位于轻链 1的分子表面 ,而且如果轻链 1在实验状态下先与肌动蛋白结合 ,则有可能影响轻链与重链间的彼此结合。肌动蛋白在体外能以不同位点结合肌球蛋白重链和轻链 ,可能在肌肉收缩过程中具有重要的生理意义

Binding of Human Cardiac Myosin Light Chain 1 to Heavy Chain and Actin

The cloning and sequence analysis of Chinese human cardiac myosin light chain 1 (CCMLC1) was previously reported. In this paper the cDNA of CCMLC1 was used as template and both of cDNAs of N and C terminal fragments of CCMLC1, each containing 98 amino acid residues, were obtained by PCR. Using the expressed products of both fragments, the binding experiments of two fragments to cardiac myosin heavy chain of rat, human cardiac actin and to monoclonal antibody raised against CCMLC1, have been performed, respectively, by means of precipitation with GST Sepharose beads. The results showed that all the heavy chain, actin and monoclonal antibody bound the N terminal fragment of CCMLC1 at different sites. Under experimental conditions, the binding of CCMLC1 with actin could affect the subsequent binding of CCMLC1 to heavy chain in topologically.