Murakawa M, Okamura T, Kamura T, Shibuya T, Harada M, Niho Y
First Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Thromb Haemost. 1993 Apr 1;69(4):351-60.
The partial amino acid sequences of fibrinogen A alpha-chains from five mammalian species have been inferred by means of the polymerase chain reaction (PCR). From the genomic DNA of the rhesus monkey, pig, dog, mouse and Syrian hamster, the DNA fragments coding for alpha-C domains in the A alpha-chains were amplified and sequenced. In all species examined, four cysteine residues were always conserved at the homologous positions. The carboxy- and amino-terminal portions of the alpha-C domains showed a considerable homology among the species. However, the sizes of the middle portions, which corresponded to the internal repeat structures, showed an apparent variability because of several insertions and/or deletions. In the rhesus monkey, pig, mouse and Syrian hamster, 13 amino acid tandem repeats fundamentally similar to those in humans and the rat were identified. In the dog, however, tandem repeats were found to consist of 18 amino acids, suggesting an independent multiplication of the canine repeats. The sites of the alpha-chain cross-linking acceptor and alpha 2-plasmin inhibitor cross-linking donor were not always evolutionally conserved. The arginyl-glycyl-aspartic acid (RGD) sequence was not found in the amplified region of either the rhesus monkey or the pig. In the canine alpha-C domain, two RGD sequences were identified at the homologous positions to both rat and human RGDS. In the Syrian hamster, a single RGD sequence was found at the same position to that of the rat. Triplication of the RGD sequences was seen in the murine fibrinogen alpha-C domain around the homologous site to the rat RGDS sequence. These findings are of some interest from the point of view of structure-function and evolutionary relationships in the mammalian fibrinogen A alpha-chains.
通过聚合酶链反应（PCR）推断出了五种哺乳动物纤维蛋白原Aα链的部分氨基酸序列。从恒河猴、猪、狗、小鼠和叙利亚仓鼠的基因组DNA中，扩增并测序了编码Aα链中α-C结构域的DNA片段。在所有检测的物种中，四个半胱氨酸残基在同源位置总是保守的。α-C结构域的羧基末端和氨基末端部分在物种间显示出相当高的同源性。然而，对应于内部重复结构的中间部分的大小由于几个插入和/或缺失而表现出明显的变异性。在恒河猴、猪、小鼠和叙利亚仓鼠中，鉴定出了与人类和大鼠基本相似的13个氨基酸串联重复序列。然而，在狗中，串联重复序列由18个氨基酸组成，表明犬类重复序列是独立倍增的。α链交联受体和α2-纤溶酶抑制剂交联供体的位点并非总是在进化上保守的。在恒河猴或猪的扩增区域中未发现精氨酰-甘氨酰-天冬氨酸（RGD）序列。在犬类α-C结构域中，在与大鼠和人类RGDS同源的位置鉴定出两个RGD序列。在叙利亚仓鼠中，在与大鼠相同的位置发现了一个RGD序列。在小鼠纤维蛋白原α-C结构域中，围绕与大鼠RGDS序列同源的位点观察到RGD序列的三倍重复。从哺乳动物纤维蛋白原Aα链的结构-功能和进化关系的角度来看，这些发现具有一定的意义。
