氨基酸和二肽组成对嗜压微生物蛋白质稳定性的影响

Influence of amino acid and dipeptide composition on protein stability of piezophilic microbes

【目的】比较嗜压和非嗜压微生物中蛋白质在氨基酸和二肽组成上的差异对嗜压蛋白稳定性机理的了解及在此基础上的定向改造具有重要意义。【方法】利用4种微生物全蛋白质组信息,统计了639对直系同源序列二级结构氨基酸组成及二肽组成并计算其偏差。【结果】在β折叠和无规则卷曲中二者差异明显,β折叠中,嗜压蛋白含更多的缬氨酸,异亮氨酸,亮氨酸,更少的精氨酸,赖氨酸,天冬氨酸;无规则卷曲中,嗜压蛋白含更多的缬氨酸和异亮氨酸,更少的甘氨酸和脯氨酸。而嗜压蛋白存在更多的YM、MN、KD、QC、CI、MW、MM、CY、WQ、HC、RC和QH,更少TW、MS、VD、DH、YE、CT、MW、CF、CK、CM、MY、QI、TH、MQ、QQ和MC。【结论】二肽比氨基酸包含更多的结构和序列信息,更有利于了解嗜压蛋白稳定性机制及指导其定向改造。

[Objective]To compare the amino acid and dipeptide composition of proteins from piezophilic and non-piezophilic microbes is of great significance for understanding the stability of piezophilic protein and directed mutation of them. [Methods] The amino acids of different secondary structure and the dipeptides of 639 orthologs proteins were counted and the deviation of them were calculated. [Results] The amino acid composition based on secondary structure and the dipeptide composition reveals some common trends.The amino acids vary widely in β sheet and coil. In β sheet, piezophilic proteins contain more amino acids such as Val, Ile and Leu, whereas less Arg, Lys and Asp; in coil, piezophilic proteins contained more amino acids such as Val and Ile, whereas less Gly and Pro. On the other hand, piezophilic proteins contain more dipeptides such as YM, MN, KD, QC, CI, MW, MM, CY, WQ, HC, RC and QH, whereas less dipeptides such as TW, MS, VD, DH, YE, CT, MW, CF, CK, CM, MY, QI, TH, MQ, QQ and MC. [Conclusion] Dipeptide contains more structure and sequence information than amino acid, and it will be more helpful for understanding the mechanism of piezophilic adaptation and guiding the engineering of proteins.