Identifying key electrostatic interactions in Rhizomucor miehei lipase:: the influence of solvent dielectric
Identifying key electrostatic interactions in Rhizomucor miehei lipase:: the influence of solvent dielectric
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DOI：
10.1007/s002140050426
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发表时间：
1999-02-01
影响因子：
1.7
通讯作者：
Caves, LSD
中科院分区：
文献类型：
--
作者：
Jääskeläinen, S;Verma, CS;Caves, LSD
与米黑根毛霉脂肪酶的界面活化相关的构象变化涉及m-螺旋盖（残基82-96）在从水（高介电）移动到脂质（低介电）时远离活性位点的位移。两种介质的介电性质非常不同的存在下，静电相互作用在这个过程中发挥了重要作用。我们已经使用线性化的泊松-玻尔兹曼计算来研究关键的静电相互作用，这有助于盖在封闭和开放状态的稳定性。盖子上的两个带电残基Arg 86和Asp 91与蛋白质的其余部分形成了最强的静电相互作用。我们确定的关键残基，其与盖子的相互作用显着扰动介质的介电变化：Asp 61，Arg 80，Lys 109，Glu 117和活性位点残基Asp 203和Asp 256，所有这些都位于约20埃的盖子。我们认为，这些残基是很好的候选人，位点特异性突变的研究，这可能有助于阐明其在脂肪酶激活机制中的作用。
The conformational change associated with the interfacial activation of Rhizomucor miehei lipase involves the displacement of an m-helical lid (residues 82-96) away from the active site on moving from water (high dielectric) to lipid (low dielectric). The presence of two media of very different dielectric properties suggests that electrostatic inter-actions play an important role in this process. We have used linearized Poisson-Boltzmann calculations to examine the key electrostatic interactions which contribute to lid stability in the closed and open states. It is the two charged residues of the lid, Arg86 and Asp91, that form the strongest electrostatic interactions with the rest of the protein. We identify key residues whose interactions with the lid are significantly perturbed by the change in the dielectric of the medium: Asp61, Arg80, Lys109, Glu117 and the active-site residues Asp203 and Asp256, all of which lie within approximately 20 Angstrom of the lid. We suggest that these residues are good candidates for site-specific mutation studies, which could help elucidate their role in the lipase activation mechanism.