Wright H T
Department of Biochemistry and Molecular Biophysics, Virginia Commonwealth University, Richmond 23298-0614.
Protein Eng. 1991 Feb;4(3):283-94. doi: 10.1093/protein/4.3.283.
The rates of deamidation of Asn and Gln residues in peptides and proteins depend upon both the identity of other nearby amino acid residues, some of which can catalyze the deamidation reaction of the Asn and Gln side chains, and upon polypeptide conformation. Proximal amino acids can be contiguous in sequence or brought close to Asn or Gln side chains by higher order structure of the protein. Local polypeptide conformation can stabilize the oxyanion transition state of the deamidation reaction and also enable deamidation through the beta-aspartyl shift mechanism. In this paper, the environments of Asn and Gln residues in known protein structures are examined to determine the configuration and identity of groups which participate in deamidation reactions. Sequence information is also analyzed and shown to support evolutionary selection against the occurrence of certain potentially catalytic amino acids adjacent to Asn and Gln in proteins. This negative selection supports a functional role for deamidation in those non-mutant proteins in which it occurs.
肽和蛋白质中天冬酰胺（Asn）和谷氨酰胺（Gln）残基的脱酰胺速率既取决于其他附近氨基酸残基的特性（其中一些残基可催化Asn和Gln侧链的脱酰胺反应），也取决于多肽的构象。近端氨基酸可以是序列上相邻的，或者通过蛋白质的高级结构靠近Asn或Gln侧链。局部多肽构象可以稳定脱酰胺反应的氧阴离子过渡态，还能通过β-天冬氨酰移位机制实现脱酰胺。在本文中，研究了已知蛋白质结构中Asn和Gln残基的环境，以确定参与脱酰胺反应的基团的构型和特性。还分析了序列信息，并表明其支持针对蛋白质中Asn和Gln附近某些潜在催化氨基酸出现的进化选择。这种负选择支持了脱酰胺在那些发生脱酰胺的非突变蛋白质中的功能作用。
