嗜压蛋白氨基酸残基溶剂可及性对其稳定性的影响

Protein piezophilicity:Solvent accessibility-based difference of amino acid in adaptation of proteins to high hydrostatic pressure

【目的】研究嗜压微生物中蛋白质在不同结构区域的特点对了解其稳定的结构基础及设计新型嗜压酶具有重要意义。【方法】利用43对嗜压和非嗜压同源蛋白的晶体结构信息,将氨基酸所处结构分成3种:分子表面、中间区及内核区,统计了不同结构状态中氨基酸的差异。【结果】统计分析结果表明,嗜压蛋白具有明显的溶剂可及性结构特点:其分子表面Cys、Asp、Asn和Lys含量显著高于非嗜压蛋白,而Pro和Arg则相反;中间区域Ile、Met含量显著高,而Trp则相反;内核区Cys、Ile含量显著高,而Ala则相反。同时,非嗜压氨基酸在嗜压蛋白分子表面及内核区含量均显著高于非嗜压蛋白。【结论】嗜压和非嗜压蛋白在分子表面差异最为明显,将是改造嗜压酶的首选区域;同时,需要统计更多的样本,对氨基酸压力不对称指数进行修订。

[Objective]To investigate the structural distribution responsible for protein piezophilicity is important for understanding the stability of piezophilic protein and would help to develop a practical strategy for designing piezophilic proteins.[Methods]We introduced a systematic comparative analysis of 43 pairs of piezophilic and non-piezophilic proteins.Three kinds of residue structural states such as external,intermediate and internal were considered for analyzing the structural patterns of single amino acids and amino acids in different groups.[Results]The statistical tests revealed that higher frequency in external state of Cys,Asp,Asn and Lys at the expense of Pro and Arg,higher frequency in intermediate state of Ile and Met at the expense of Trp,higher frequency in internal state of Cys and Ile at the expense of Ala,higher frequency in external and internal state of non-barophilic amino acids groups,lower frequency in external state of neutral and large amino acids groups could be critical factors related with protein piezophilicity.[Conclusion]The external state was the domain that had the most differences between piezophilic and non-piezophilic proteins,and it should be a hot spot for designing and engineering new piezophilic proteins.At the same time,the pressure asymmetry index should be revised based on more datasets.