Poteete A R, Rennell D, Bouvier S E, Hardy L W
Department of Molecular Genetics & Microbiology, University of Massachusetts Medical Center, Worcester 01655, USA.
Protein Sci. 1997 Nov;6(11):2418-25. doi: 10.1002/pro.5560061115.
Mutations that suppress the defects introduced into T4 lysozyme by single amino acid substitutions were isolated and characterized. Among 53 primary sites surveyed, 8 yielded second-site revertants; a total of 18 different mutants were obtained. Most of the restorative mutations exerted global effects, generally increasing lysozyme function in a number of primary mutant contexts. Six of them were more specific, suppressing only certain specific deleterious primary substitutions, or diminishing the function of lysozymes bearing otherwise nondeleterious primary substitutions. Some variants of proteins bearing primary substitutions at the positions of Asp 20 and Ala 98 are inferred to have significantly altered structures.
分离并鉴定了能够抑制因单个氨基酸替换而引入到T4溶菌酶中的缺陷的突变。在所研究的53个主要位点中，有8个产生了第二位点回复突变体；总共获得了18个不同的突变体。大多数恢复性突变具有全局性影响，通常在许多主要突变背景下增强溶菌酶功能。其中6个更具特异性，仅抑制某些特定的有害主要替换，或降低携带其他无害主要替换的溶菌酶的功能。推断在Asp 20和Ala 98位置带有主要替换的蛋白质的一些变体具有显著改变的结构。
