咪唑鎓离子液体对酶结构影响的晶体学研究
Crystallographic Investigation of Imidazolium Ionic Liquid Effects on Enzyme Structure.
作者信息
Nordwald Erik M, Plaks Joseph G, Snell Jared R, Sousa Marcelo C, Kaar Joel L
机构信息
Department of Chemical and Biological Engineering, University of Colorado, Campus Box 596, Boulder, CO, 80309, USA.
Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, 80309, USA.
出版信息
Chembiochem. 2015 Nov;16(17):2456-9. doi: 10.1002/cbic.201500398. Epub 2015 Oct 14.
We present the first crystallographic insight into the interactions of an ionic liquid (IL) with an enzyme, which has widespread implications for stabilizing enzymes in IL media for biocatalysis. Structures of Bacillus subtilis lipase A (lipA) and an IL-stable variant (QM-lipA) were obtained in the presence of increasing concentrations of 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]). These studies revealed that the [BMIM] cation interacts with surface residues through hydrophobic and cation-π interactions. Of specific interest was the disruption of internal stacking interactions of aromatic side chains by [BMIM], which provides structural evidence for the mechanism of enzyme denaturation by ILs. The interaction of [BMIM] and Cl ions with lipA was reduced by the stabilizing mutations Y49E and G158E in QM-lipA. Ultimately, these findings present the molecular basis for stabilizing enzymes from IL-induced inactivation, as well as the selection of ILs that are less denaturing.
我们首次通过晶体学深入了解了离子液体（IL）与酶之间的相互作用，这对于在IL介质中稳定酶以进行生物催化具有广泛的意义。在1-丁基-3-甲基咪唑氯化物（[BMIM][Cl]）浓度不断增加的情况下，获得了枯草芽孢杆菌脂肪酶A（lipA）和IL稳定变体（QM-lipA）的结构。这些研究表明，[BMIM]阳离子通过疏水作用和阳离子-π相互作用与表面残基相互作用。特别值得关注的是，[BMIM]破坏了芳香族侧链的内部堆积相互作用，这为IL使酶变性的机制提供了结构证据。QM-lipA中的稳定突变Y49E和G158E减少了[BMIM]和Cl离子与lipA的相互作用。最终，这些发现为稳定酶以防止IL诱导的失活提供了分子基础，同时也为选择变性作用较小的IL提供了依据。
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