Single-molecule enzymatic dynamics
Single-molecule enzymatic dynamics
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DOI：
10.1126/science.282.5395.1877
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发表时间：
1998-12-04
期刊：
影响因子：
56.9
通讯作者：
Xie, XS
中科院分区：
文献类型：
--
作者：
Lu, HP;Xun, LY;Xie, XS
通过监测酶的荧光活性部位黄素腺嘌呤二核苷酸(FAD)的发射，实时观察到单一胆固醇氧化酶分子的酶转化，单分子轨迹的统计分析表明FAD对胆固醇的氧化速度有显著而缓慢的波动。反应速率的静态无序和动态无序在系综平均实验中基本上是无法区分的，它们是通过实时单分子方法分别确定的。FAD的自发光谱波动证明了一种分子记忆现象，即由于蛋白质构象的缓慢波动，酶的翻转并不独立于之前的翻转。
Enzymatic turnovers of single cholesterol oxidase molecules were observed in real time by monitoring the emission from the enzyme's fluorescent active site, flavin adenine dinucleotide (FAD), Statistical analyses of single-molecule trajectories revealed a significant and slow fluctuation in the rate of cholesterol oxidation by FAD. The static disorder and dynamic disorder of reaction rates, which are essentially indistinguishable in ensemble-averaged experiments, were determined separately by the real-time single-molecule approach. A molecular memory phenomenon, in which an enzymatic turnover was not independent of its previous turnovers because of a slow fluctuation of protein conformation, was evidenced by spontaneous spectral fluctuation of FAD.