The H385N mutant of 5-enolpyruvylshikimate-3-phosphate synthase: kinetics, fluorescence, and nuclear magnetic resonance studies.
The H385N mutant of 5-enolpyruvylshikimate-3-phosphate synthase: kinetics, fluorescence, and nuclear magnetic resonance studies.
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5-烯醇丙酮莽草酸-3-磷酸合酶的 H385N 突变体：动力学、荧光和核磁共振研究。
DOI：
10.1006/abbi.1996.0426
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Evans,JN
中科院分区：
文献类型：
--
作者：
Shuttleworth,WA;Evans,JN
报道了5-烯醇式莽草酸-3-磷酸（EPSP）合成酶组氨酸385位的定点突变。通过多种方法将H385 N突变体与野生型进行比较。发现H385 N保留6%活性。动力学参数，包括天然底物的Km值和抑制剂草甘膦的Ki和Kd值，被发现与野生型相似。与野生型酶不同，H385 N EPSP合酶在平衡条件下的13 C NMR谱中不显示酶结合产物（EPSP）的积累。这些结果表明，该H385 N突变体的催化活性低于先前研究的H385 Q突变体，并且组氨酸的N-组氨酸可能参与与另一个参与络合底物/产物的残基的氢键合。
The site-directed mutagenesis of histidine-385 of 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase is reported. The H385N mutant is compared with wild type by a number of methods. H385N was found to retain 6% activity. Kinetic parameters, includingKmvalues for the natural substrates andKiandKdvalues for the inhibitor glyphosate, were found to be similar to wild type. Unlike wild-type enzyme, H385N EPSP synthase does not show accumulation of enzyme-bound product (EPSP) in the13C NMR spectrum under equilibrium conditions. These results suggest that this H385N mutant is less catalytically competent than the previously studied H385Q mutant and that the NϵH of histidine may be involved in hydrogen bonding to another residue involved in complexing the substrates/products.