应用残基相互作用探讨嗜热和嗜冷酶稳定机制

为探寻嗜热酶和嗜冷酶稳定性的机制,提出一种基于蛋白分子内残基相互作用的方法.结果表明:在一级结构上,差异不明显的同源嗜热、常温、嗜冷酶在不同残基相互作用次数时,存在非常显著的差异;嗜热酶中,高相互作用次数的氨基酸及氨基酸类型与其同源常温酶差异最大,嗜热酶减少低相互作用次数的氨基酸,而增加高相互作用次数的氨基酸是其适应高温的普遍机制,嗜冷酶也存在类似趋势,但不如嗜热酶明显;同一个氨基酸在不同相互作用次数时,作用存在差异,这可解释现有一些相互矛盾的实验结果.

Insight into Stability Mechanism of Thermophilic and Psychrophilic Enzymes Using Residue Interaction Networks

A novel method is proposed to explore the stable mechanism of thermophilic and psychrophilic enzymes based on the residue interaction network. The results clearly indicated that the thermophilic-mesophilic-psychrophilic homologs having no significant differences in sequence showed great significant differences according to various numbers of interactions in terms of amino acid composition. The amino acids and amino acid kinds varied remarkably at high degree of interactions between the thermophilic and mesophilic enzymes. At the same time, the thermophilic enzymes preferred amino acids with more interactions at the expense of those with less interaction, which may be a general rule for their adaptation to high temperature. The trends also existed in the psychrophilic enzyme, although it was not so obvious. Besides, the amino acid had contrary contributions to the stability of the enzymes at different degrees of interactions. That might be the reason that some references had opposite results.