Miyata T, Aruga R, Umeyama H, Bezeaud A, Guillin M C, Iwanaga S
Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan.
Biochemistry. 1992 Aug 25;31(33):7457-62. doi: 10.1021/bi00148a005.
Structural studies on a hereditary abnormal prothrombin, prothrombin Salakta, have been performed to identify the difference responsible for its reduced fibrinogen clotting activity and its reduced esterase activity. Amino acid composition and sequence analyses of a peptide isolated from a lysylendopeptidase digest of the abnormal thrombin indicated that Glu-466 had been replaced by Ala. This amino acid substitution can result from a single nucleotide change in the codon for Glu-466 (GAG----GCG). The model building and the molecular dynamics simulation of thrombin Salakta suggest that the Glu-466----Ala substitution would change the proper conformation around the substrate binding site containing Trp-468, which is a unique surface loop on the thrombin molecule. This is the experimental and theoretical evidence supporting the role of the surface loop containing Trp-468 for the proper conformation of the substrate binding site.
对一种遗传性异常凝血酶原——凝血酶萨拉克塔进行了结构研究，以确定导致其纤维蛋白原凝血活性降低和酯酶活性降低的差异。从异常凝血酶的赖氨酰内肽酶消化物中分离出的一种肽的氨基酸组成和序列分析表明，谷氨酸-466已被丙氨酸取代。这种氨基酸取代可能是由于谷氨酸-466密码子中的单个核苷酸变化（GAG----GCG）引起的。凝血酶萨拉克塔的模型构建和分子动力学模拟表明，谷氨酸-466----丙氨酸取代会改变包含色氨酸-468的底物结合位点周围的正确构象，色氨酸-468是凝血酶分子上一个独特的表面环。这是支持包含色氨酸-468的表面环对底物结合位点正确构象起作用的实验和理论证据。
