Enzyme structure and dynamics affect hydrogen tunneling: The impact of a remote side chain (1553) in soybean lipoxygenase-1
Enzyme structure and dynamics affect hydrogen tunneling: The impact of a remote side chain (1553) in soybean lipoxygenase-1
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DOI：
10.1073/pnas.0710643105
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发表时间：
2008-01-29
影响因子：
11.1
通讯作者：
Klinman, Judith P.
中科院分区：
文献类型：
--
作者：
Meyer, Matthew P.;Tomchick, Diana R.;Klinman, Judith P.
本研究探讨了大豆脂肪氧合酶-1（SLO-1）553位的一系列突变对酶动力学和结构特性的影响。本文报道的先前未表征的突变体是1553 L、1553 V和1553 G。这些突变体的高分辨率X射线研究，以及早期研究的1553 A，显示几乎没有结构变化的WT-酶。相比之下，动力学行为发生进展，其中在位置553处的侧链的尺寸的减小导致在氢转移过程中供体-受体距离取样的重要性增加。这些行为的动态变化在两种一般类型的蛋白质运动的背景下进行解释，即预组织和重组，后者包括距离采样模式[Klinman JP（2006）Philos Trans R Soc伦敦Ser B 361：1323-1331;内格尔Z，Klinman JP（2006）Chem Rev 106：3095-3118]。SLO-1的聚集数据显示了疏水侧链的明智放置如何通过增强的供体-受体类氢波函数重叠来影响酶催化。
This study examines the impact of a series of mutations at position 553 on the kinetic and structural properties of soybean lipoxygenase-1 (SLO-1). The previously uncharacterized mutants reported herein are 1553L, 1553V, and 1553G. High-resolution x-ray studies of these mutants, together with the earlier studied 1553A, show almost no structural change in relation to the WT-enzyme. By contrast, a progression in kinetic behavior occurs in which the decrease in the size of the side chain at position 553 leads to an increased importance of donor-acceptor distance sampling in the course of the hydrogen transfer process. These dynamical changes in behavior are interpreted in the context of two general classes of protein motions, preorganization and reorganization, with the latter including the distance sampling modes [Klinman JP (2006) Philos Trans R Soc London Ser B 361:1323-1331; Nagel Z, Klinman JP (2006) Chem Rev 106:3095-3118]. The aggregate data for SLO-1 show how judicious placement of hydrophobic side chains can influence enzyme catalysis via enhanced donor-acceptor hydrogenic wave function overlap.