Department of Biotechnology, Indian Institute of Technology, Guwahati 781039, Assam, India.
Appl Biochem Biotechnol. 2012 Jun;167(3):439-61. doi: 10.1007/s12010-012-9669-9. Epub 2012 May 5.
Organic solvent-stable lipases have pronounced impact on industrial economy as they are involved in synthesis by esterification, interesterification, and transesterification. However, very few of such natural lipases have been isolated till date. A study of the recent past provided few pillars to rely on for this work. The three-dimensional structure, inclusive of the surface and active site, of 29 organic solvent-stable lipases was analyzed by subfamily classification and protein solvent molecular docking based on fast Fourier transform correlation approach. The observations revealed that organic solvent stability of lipases is their intrinsic property and unique with respect to each lipase. In this paper, factors like surface distribution of charged, hydrophobic, and neutral residues, interaction of solvents with catalytically immutable residues, and residues interacting with essential water molecules required for lipase activity, synergistically and by mutualism contribute to render a stable lipase organic solvent. The propensity of surface charge in relation to stability in organic solvents by establishing repulsive forces to exclude solvent molecules from interacting with the surface and prohibiting the same from gaining entry to the protein core, thus stabilizing the active conformation, is a new finding. It was also interesting to note that lipases having equivalent surface-exposed positive and negative residues were stable in a wide range of organic solvents, irrespective of their LogP values.
有机溶剂稳定脂肪酶在工业经济中具有显著的影响，因为它们参与酯化、酯交换和转酯化的合成。然而，到目前为止，只有极少数天然脂肪酶被分离出来。对过去的研究进行的研究为这项工作提供了一些依据。通过亚家族分类和基于快速傅里叶变换相关方法的蛋白质溶剂分子对接，分析了 29 种有机溶剂稳定脂肪酶的三维结构，包括表面和活性位点。观察结果表明，脂肪酶的有机溶剂稳定性是其内在特性，并且每种脂肪酶都具有独特性。在本文中，表面分布的带电、疏水和中性残基、溶剂与催化不变残基的相互作用以及与脂肪酶活性所需的必需水分子相互作用的因素，通过相互促进和相互作用，有助于使脂肪酶在有机溶剂中稳定。通过建立排斥力使溶剂分子无法与表面相互作用并防止其进入蛋白质核心，从而稳定活性构象，表面电荷与有机溶剂稳定性之间的关系的倾向是一个新发现。有趣的是，表面暴露的正负残基相等的脂肪酶在广泛的有机溶剂中都很稳定，而与它们的 LogP 值无关。
