Dramatic thermostabilization of yeast iso-1-cytochrome c by an asparagine----isoleucine replacement at position 57.
Dramatic thermostabilization of yeast iso-1-cytochrome c by an asparagine----isoleucine replacement at position 57.
复制标题
通过第 57 位天冬酰胺----异亮氨酸的替代，酵母 iso-1-细胞色素 c 具有显着的热稳定性。
DOI：
10.1073/pnas.86.2.496
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发表时间：
1989
影响因子：
11.1
通讯作者：
Sherman,F
中科院分区：
文献类型：
--
作者：
Das,G;Hickey,DR;McLendon,D;McLendon,G;Sherman,F
两个酿酒酵母酵母突变体，cyc 1 -73和cyc 1 -190，含有非功能性和推测不稳定的形式的异-1-细胞色素c由于甘氨酸-34-丝氨酸和组氨酸-38-Pro的替代，分别。产生Asn-57-Ile替代的第二位点回复至少部分恢复了功能，推测是通过减轻这两种改变的iso-1-细胞色素的不稳定性。通过定点诱变在其他正常蛋白质中引入Ile-57置换导致转变温度（Tm）增加17 ℃，对应于热去折叠的自由能变化（Δ G度）增加超过2倍。
Two Saccharomyces cerevisiae yeast mutants, cyc1-73 and cyc1-190, contain nonfunctional and presumably unstable forms of iso-1-cytochrome c due to Gly-34----Ser and His-38----Pro replacements, respectively. Second-site reversions that produced Asn-57----Ile replacements at least partially restored function, presumably by alleviating the instability of these two altered iso-1-cytochromes c. Introduction of the Ile-57 replacement by site-directed mutagenesis in an otherwise normal protein resulted in a 17 degrees C increase in the transition temperature (Tm), corresponding to over a 2-fold increase in the free energy change (delta G degrees) for thermal unfolding.