Williams M J, Phan I, Harvey T S, Rostagno A, Gold L I, Campbell I D
Department of Biochemistry, University of Oxford, U.K.
J Mol Biol. 1994 Jan 28;235(4):1302-11. doi: 10.1006/jmbi.1994.1083.
The tertiary structure of the fourth and fifth type 1 module pair from the N terminus of human fibronectin, has been determined by two-dimensional homonuclear 1H nuclear magnetic resonance (NMR) spectroscopy. Comparison of each module fold with those of two other type 1 modules shows that the type 1 "consensus" structure is conserved in the pair. The modules connect end-to-end to form an elongated structure with a limited clockwise twist around the long axis, from N to C terminus. The short five residue linker sequence forms a tight loop and the relative orientation of the two modules is maintained by fixed and intimate hydrophobic contacts, dominated by a non-conserved tryptophan residue from the fourth type 1 module. The protein binds specifically to fibrin in an ELISA and surface accessible residues that may be involved in this and other protein interactions can be identified. The structure provides an insight into how chains of type 1 modules may link up in intact fibronectin.
通过二维同核1H核磁共振（NMR）光谱法，已确定了人纤连蛋白N端第四和第五个1型模块对的三级结构。将每个模块折叠与其他两个1型模块的折叠进行比较，结果表明该对模块中1型“共有”结构是保守的。这些模块首尾相连，形成一个细长结构，从N端到C端围绕长轴有有限的顺时针扭曲。短的五个残基连接子序列形成一个紧密环，两个模块的相对取向通过固定且紧密的疏水接触得以维持，这种接触主要由第四个1型模块中一个非保守的色氨酸残基主导。在酶联免疫吸附测定（ELISA）中，该蛋白能特异性结合纤维蛋白，并且可以鉴定出可能参与这种及其他蛋白相互作用的表面可及残基。该结构为深入了解1型模块链在完整纤连蛋白中如何连接提供了线索。
