Argos P, Hanei M, Wilson J M, Kelley W N
J Biol Chem. 1983 May 25;258(10):6450-7.
Comparison of the primary structures of three phosphoribosyltransferases (human hypoxanthine-guanine, Salmonella typhimurium ATP, and Escherichia coli glutamine) showed no significant amino acid sequence homology except for a 35-residue span in hypoxanthine-guanine and glutamine phosphoribosyltransferases. However, comparison of smoothed plots of amino acid physical characteristics thought to control protein folding with amino acid sequence number resulted in a substantial correlation for a 120-residue stretch in each of the phosphoribosyltransferases. A secondary structure prediction analysis of the regions indicated a dinucleotide-binding fold with its characteristic beta alpha beta secondary structural pattern. Furthermore, the physical parametric correlation analysis suggested a common catalytic domain fold for hypoxanthine-guanine and glutamine phosphoribosyltransferases which was consistent with the register of the sequence homology. A possible binding mode of the phosphoribosyltransferase substrates is discussed. The physical parametric approach to protein sequence comparison may be generally applicable for distantly related proteins which maintain similar structural folds without any apparent sequence homology.
对三种磷酸核糖转移酶（人次黄嘌呤 - 鸟嘌呤磷酸核糖转移酶、鼠伤寒沙门氏菌ATP磷酸核糖转移酶和大肠杆菌谷氨酰胺磷酸核糖转移酶）的一级结构进行比较，结果显示，除了次黄嘌呤 - 鸟嘌呤磷酸核糖转移酶和谷氨酰胺磷酸核糖转移酶中有一段35个残基的序列外，它们之间没有明显的氨基酸序列同源性。然而，将被认为控制蛋白质折叠的氨基酸物理特性的平滑图与氨基酸序列编号进行比较时，发现每种磷酸核糖转移酶中一段120个残基的区域存在显著相关性。对这些区域进行的二级结构预测分析表明，它们具有二核苷酸结合折叠及其特征性的β-α-β二级结构模式。此外，物理参数相关性分析表明，次黄嘌呤 - 鸟嘌呤磷酸核糖转移酶和谷氨酰胺磷酸核糖转移酶具有共同的催化结构域折叠，这与序列同源性的比对结果一致。文中还讨论了磷酸核糖转移酶底物可能的结合模式。蛋白质序列比较的物理参数方法可能普遍适用于那些保持相似结构折叠但没有明显序列同源性的远缘相关蛋白质。
