Patthy L, Trexler M, Váli Z, Bányai L, Váradi A
FEBS Lett. 1984 Jun 4;171(1):131-6. doi: 10.1016/0014-5793(84)80473-1.
Prothrombin, plasminogen, urokinase- and tissue-type plasminogen activators contain homologous structures known as kringles . The kringles correspond to autonomous structural and folding domains which mediate the binding of these multidomain proteins to other proteins. During evolution the different kringles retained the same gross architecture, the kringle -fold, yet diverged to bind different proteins. We show that the amino acid sequences of the type II structures of the gelatin-binding region of fibronectin are homologous with those of the protease- kringles . Prediction of secondary structures revealed a remarkable agreement in the positions of predicted beta-sheets, suggesting that the folding of kringles and type II structures may also be similar. As a corollary of this finding, the disulphide-bridge pattern of type II structures is shown to be homologous to that in kringles . It is noteworthy that protease- kringles and fibronectin type II structures have similar functions inasmuch as they mediate the binding of multidomain proteins to other proteins. It is proposed that the kringles of proteases and type II structures of fibronectin evolved from a common ancestral protein binding module.
凝血酶原、纤溶酶原、尿激酶型和组织型纤溶酶原激活剂含有被称为kringle的同源结构。这些kringle对应于自主的结构和折叠结构域，介导这些多结构域蛋白与其他蛋白的结合。在进化过程中，不同的kringle保留了相同的总体结构，即kringle折叠，但在结合不同蛋白方面发生了分化。我们发现，纤连蛋白明胶结合区域的II型结构的氨基酸序列与蛋白酶kringle的氨基酸序列同源。二级结构预测显示，预测的β-折叠位置有显著一致性，这表明kringle和II型结构的折叠可能也相似。作为这一发现的必然结果，II型结构的二硫键模式被证明与kringle中的二硫键模式同源。值得注意的是，蛋白酶kringle和纤连蛋白II型结构具有相似的功能，因为它们介导多结构域蛋白与其他蛋白的结合。有人提出，蛋白酶的kringle和纤连蛋白的II型结构是从一个共同的祖先蛋白结合模块进化而来的。
