Chen G X, Tan R Y, Gong Z X, Huang Y P, Wang S Z, Cao T G
Shanghai Institute of Biochemistry, Chinese Academy of Sciences, China.
Biophys Chem. 1988 Feb;29(1-2):147-53. doi: 10.1016/0301-4622(88)87034-0.
We propose here the formation by molluscan and notochord muscles in the catch state of three-dimensional, entangled network structures composed of bent and sometimes entwined paramyosin thick filaments including myosin intermediate filaments and disordered actin thin filaments; in the relaxed state the three forms lie in parallel. The intact forms of bivalve (Andonta pacifica, Heude) muscle paramyosin are those of 120 and 95 kDa (beta-paramyosin). The 102 kDa form (alpha-paramyosin) is the proteinase cleavage product of 120 kDa paramyosin. Paramyosin could be phosphorylated in vitro by cyclic AMP-dependent protein kinase. The amino acid phosphorylated was at the serine residue. Paramyosin from muscles treated with acetylcholine (catch state) was phosphorylated to a greater extent than that of untreated muscles (normal state) and even more so in the case of serotonin-treated muscles (relaxed state). Actin markedly inhibited the phosphorylation of paramyosin in vitro.
我们在此提出，在捕获状态下，软体动物和脊索动物的肌肉会形成三维纠缠网络结构，该结构由弯曲且有时相互缠绕的副肌球蛋白粗丝组成，其中包括肌球蛋白中间丝和无序的肌动蛋白细丝；在松弛状态下，这三种形式平行排列。双壳类（太平洋安冬蛤，海登）肌肉副肌球蛋白的完整形式为120 kDa和95 kDa（β-副肌球蛋白）。102 kDa形式（α-副肌球蛋白）是120 kDa副肌球蛋白的蛋白酶裂解产物。副肌球蛋白在体外可被环磷酸腺苷依赖性蛋白激酶磷酸化。磷酸化的氨基酸是丝氨酸残基。用乙酰胆碱处理的肌肉（捕获状态）中的副肌球蛋白比未处理的肌肉（正常状态）磷酸化程度更高，而在用5-羟色胺处理的肌肉（松弛状态）中更是如此。肌动蛋白在体外显著抑制副肌球蛋白的磷酸化。
