Effect of mutation on enzyme motion in dihydrofolate reductase.
Effect of mutation on enzyme motion in dihydrofolate reductase.
复制标题
突变对二氢叶酸还原酶酶运动的影响。
DOI：
10.1021/ja028487u
复制
发表时间：
2003
影响因子：
15
通讯作者：
Hammes-Schiffer,Sharon
中科院分区：
文献类型：
--
作者：
Watney,JamesB;Agarwal,PratulK;Hammes-Schiffer,Sharon
采用量子-经典分子动力学方法对大肠杆菌二氢叶酸还原酶进行了模拟。尽管残基121位于酶的外部，但实验研究表明，Gly-121突变为缬氨酸会使氢转移速率降低163倍。模拟表明，G121 V突变体的氢化物转移速率的降低是由于自由能垒的增加。计算的自由能势垒是高的突变体比野生型酶的量是一致的实验观察到的速率降低。野生型和突变型酶的计算透射系数相当。模拟结果表明，这种突变可能会中断网络的耦合促进运动提出发挥重要作用的DHFR催化。这种现象对蛋白质工程和药物设计具有广泛的意义。
Hybrid quantum-classical molecular dynamics simulations of a mutantEscherichia colidihydrofolate reductase enzyme are presented. Although residue 121 is on the exterior of the enzyme, experimental studies have shown that the mutation of Gly-121 to valine reduces the rate of hydride transfer by a factor of 163. The simulations indicate that the decrease in the hydride transfer rate for the G121V mutant is due to an increase in the free energy barrier. The calculated free energy barrier is higher for the mutant than for the wild-type enzyme by an amount that is consistent with the experimentally observed rate reduction. The calculated transmission coefficients are comparable for the wild-type and mutant enzymes. The simulations suggest that this mutation may interrupt a network of coupled promoting motions proposed to play an important role in DHFR catalysis. This phenomenon has broad implications for protein engineering and drug design.