通过旋光性对肌肉蛋白质构象的重新检测。

Reexamination of the conformation of muscle proteins by optical activity.

作者信息

Wu C S, Yang J T

出版信息

Biochemistry. 1976 Jul 13;15(14):3007-14. doi: 10.1021/bi00659a011.

Abstract

The circular dichroism and optical rotatory dispersion of muscle proteins are reexamined. By the method of Chen et al. (Chen, Y.H., Yang, J.T., and Chau, K.H. (1974), Biochemistry 13, 3350), the estimated helical contents of myosin (78%), heavy meromyosin (HMM) (70%) subfragment 1 (SF-1) (60%), and G-actin (45%) are higher than hitherto reported. Tropomyosin (TM) and light meromyosin fraction I (LMM Fr. I) possess more than 90% helix in agreement with the values based on the bo method. HMM, SF-1, and G-actin also contain about 8, 16, and 27% beta form. The three troponins (TN) and three light chains (LC) of myosin have moderate amounts of helices (29 to 51%) and some beta form (13 to 23%). If the light chains are intact in HMM and SF-1, myosin would have 3-5% beta form, which is difficult to detect with the present method. For comparison, the predictive method based on amino acid sequence gives similar estimates for TM, G-actin, and TN-C with bound calcium, but slightly higher helical contents than our results for TN-I and the light chains.

摘要

对肌肉蛋白质的圆二色性和旋光色散进行了重新研究。采用Chen等人的方法（Chen, Y.H., Yang, J.T., and Chau, K.H. (1974), Biochemistry 13, 3350），估计肌球蛋白的螺旋含量为78%，重酶解肌球蛋白（HMM）为70%，亚片段1（SF-1）为60%，G-肌动蛋白为45%，均高于迄今报道的值。原肌球蛋白（TM）和轻酶解肌球蛋白组分I（LMM Fr. I）的螺旋含量超过90%，这与基于bo方法得到的值一致。HMM、SF-1和G-肌动蛋白还含有约8%、16%和27%的β结构。肌球蛋白的三种肌钙蛋白（TN）和三种轻链（LC）具有适量的螺旋结构（29%至51%）和一些β结构（13%至23%）。如果轻链在HMM和SF-1中保持完整，肌球蛋白将含有3%至5%的β结构，这用目前的方法很难检测到。作为比较，基于氨基酸序列的预测方法对TM、G-肌动蛋白和结合钙的TN-C给出了类似的估计，但对TN-I和轻链的螺旋含量估计略高于我们的结果。