Ohta T
National Institute of Genetics, Mishima, Japan.
J Mol Evol. 1994 Dec;39(6):614-9. doi: 10.1007/BF00160406.
The pattern of synonymous and nonsynonymous substitutions at the reactive center of proteases (kallikrein) and their inhibitors (alpha 1-antitrypsin and serpin) was examined. In the case of alpha 1-antitrypsin, the proportion of different nonsynonymous sites exceeds that of different synonymous sites at the reactive center for sequence pairs of recent duplication. The result indicates that the positive selection has operated after duplication to increase functional diversity. In the cases of kallikrein, serpin, and remote sequence pairs of alpha 1-antitrypsin, the proportion of different synonymous sites at the reactive center exceeds that of different synonymous sites at the remaining region. The result indicates that gene conversion followed by natural selection is working. On the whole, it is concluded that hypervariability of amino acids at the reactive center is generated by an interaction among natural selection, random genetic drift, point mutation, and gene conversion. Gene duplication may provide potential for them to interact.
研究了蛋白酶（激肽释放酶）及其抑制剂（α1-抗胰蛋白酶和丝氨酸蛋白酶抑制剂）反应中心的同义替换和非同义替换模式。就α1-抗胰蛋白酶而言，对于近期复制的序列对，反应中心不同非同义位点的比例超过了不同同义位点的比例。结果表明，复制后正向选择起作用以增加功能多样性。在激肽释放酶、丝氨酸蛋白酶抑制剂以及α1-抗胰蛋白酶的远缘序列对的情况下，反应中心不同同义位点的比例超过了其余区域不同同义位点的比例。结果表明基因转换随后伴随自然选择在起作用。总体而言，得出的结论是，反应中心氨基酸的高变异性是由自然选择、随机遗传漂变、点突变和基因转换之间的相互作用产生的。基因复制可能为它们的相互作用提供了潜力。
