对嗜压蛋白氨基酸压力不对称指数的修订

Revision of the Amino Acid Pressure Asymmetry Index of Piezophilic Proteins

选取嗜压菌最多的4种希瓦氏菌属(Shewanella)微生物共计473对同源蛋白,统计了21 662个氨基酸突变位点,在此基础上计算氨基酸压力不对称指数(PAI),并将其同氨基酸70种理化性质进行相关性分析.结果表明:色氨酸和异亮氨酸的嗜压性能最强,而脯氨酸、甘氨酸和天冬酰胺的嗜压性能最弱,这与之前的报道存在较大差异.此外,70种氨基酸理化性质中有13种同PAI存在较强的相关性,其中仅有氨基酸的无规则倾向因子同PAI呈负相关,表明高的PAI值不易形成卷曲.由于展示的PAI值更适合于处于低温环境下的嗜压微生物,因此对以前的PAI值进行了修正.

A comparison was made between 473 orthologous proteins from Shewanella.The pattern of asymmetries in the 21 662 amino acid mutation sites reveals some common trends.The pressure asymmetry index（PAI） identifies the amino acids tryptophan（Trp） and isoleucine（Ile） as those having the most piezophilic behavior,and proline（Pro）,glycine（Gly） and asparagines（Asn） as the least piezophilic,which is totally different from the former result.The PAI makes it possible to visualize the amino acid properties that best explain piezophily.Among the 70 properties of amino acids,there are 13 significantly correlated with PAI value.Only the coil tendencies are negatively correlated with PAI value,that is to say,on average,higher PAI values are associated with fewer tendencies to form coil.The PAI we established here may be more suitable to the piezophiles living in the cold environment,and a revision of the previous PAI values was made.