Electron tunneling through sensitizer wires bound to proteins.
Electron tunneling through sensitizer wires bound to proteins.
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DOI：
10.1016/j.ccr.2009.08.008
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发表时间：
2010-02-01
影响因子：
20.6
通讯作者：
Ratner MA
中科院分区：
文献类型：
--
作者：
Hartings MR;Kurnikov IV;Dunn AR;Winkler JR;Gray HB;Ratner MA
我们报告了一个定量的理论分析，通过敏化剂线绑定在细胞色素P450 cam的活性位点通道的远程电子转移。每个敏化剂线由对酶活性位点具有高结合亲和力的底物基团组成，所述底物基团通过桥接脂肪族或芳香族链连接至二亚胺。实验已经揭示了电子转移速率对桥连基团和衬底的化学组成的戏剧性依赖。使用结合分子动力学模拟和电子耦合计算，我们表明，通过全氟芳族桥的电子隧穿促进通过虚拟还原态增强超交换耦合。相反，通过脂肪族桥的电子流通过空穴介导的超交换发生。我们已经发现，少量的线构象与强供体-受体耦合可以解释所观察到的电子隧穿率的敏化剂线终止于或金刚烷。在这些情况下，该速率不仅取决于供体和受体的电子耦合，而且取决于敏化剂线的核运动，从而需要计算分子动力学模拟过程中的平均速率。这些计算沿着相关的最新发现，使我们有可能分析许多其他敏化线实验的结果，反过来指出新的方向，在我们试图观察活性中间体的催化循环的P450和其他血红素酶。
We report a quantitative theoretical analysis of long-range electron transfer through sensitizer wires bound in the active-site channel of cytochrome P450cam. Each sensitizer wire consists of a substrate group with high binding affinity for the enzyme active site connected to a ruthenium-diimine through a bridging aliphatic or aromatic chain. Experiments have revealed a dramatic dependence of electron transfer rates on the chemical composition of both the bridging group and the substrate. Using combined molecular dynamics simulations and electronic coupling calculations, we show that electron tunneling through perfluorinated aromatic bridges is promoted by enhanced superexchange coupling through virtual reduced states. In contrast, electron flow through aliphatic bridges occurs by hole-mediated superexchange. We have found that a small number of wire conformations with strong donor-acceptor couplings can account for the observed electron tunneling rates for sensitizer wires terminated with either ethylbenzene or adamantane. In these instances, the rate is dependent not only on electronic coupling of the donor and acceptor but also on the nuclear motion of the sensitizer wire, necessitating the calculation of average rates over the course of a molecular dynamics simulation. These calculations along with related recent findings have made it possible to analyze the results of many other sensitizer-wire experiments that in turn point to new directions in our attempts to observe reactive intermediates in the catalytic cycles of P450 and other heme enzymes.
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影响因子：
15
作者：
Dunn, AR;Hays, AMA;Gray, HB
通讯作者：
Gray, HB
影响因子：
15
作者：
Dunn, AR;Belliston-Bittner, W;Gray, HB
通讯作者：
Gray, HB
影响因子：
16.6
作者：
Mayor, M;Weber, HB
通讯作者：
Weber, HB
影响因子：
56.9
作者：
Balabin, IA;Onuchic, JN
通讯作者：
Onuchic, JN
DOI：
10.1073/pnas.96.23.12987
发表时间：
1999-11-09
影响因子：
11.1
作者：
Dmochowski, IJ;Crane, BR;Gray, HB
通讯作者：
Gray, HB