DIRECT EVALUATION OF ELECTRONIC COUPLING MEDIATED BY HYDROGEN-BONDS - IMPLICATIONS FOR BIOLOGICAL ELECTRON-TRANSFER
DIRECT EVALUATION OF ELECTRONIC COUPLING MEDIATED BY HYDROGEN-BONDS - IMPLICATIONS FOR BIOLOGICAL ELECTRON-TRANSFER
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DOI：
10.1126/science.7660123
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发表时间：
1995-09-08
期刊：
影响因子：
56.9
通讯作者：
THERIEN, MJ
中科院分区：
文献类型：
--
作者：
DEREGE, PJF;WILLIAMS, SA;THERIEN, MJ
三个超分子bischromophoric系统具有锌（II）和铁（III）卟啉已被合成，以评估由氢，σ，π键提供的电子耦合的相对幅度。激光闪光激发产生的高度还原的单重激发态的（卟啉）锌发色团，随后可以通过（卟啉）氯化铁（III）部分的电子转移淬灭。光诱导电子转移速率常数的测量使得能够直接比较这三种类型的化学相互作用促进电子隧穿的程度。与普遍接受的理论相反，由氢键界面调制的电子耦合大于由完全由碳-碳a键组成的类似界面提供的电子耦合。这些结果承担相当大的分析，通过蛋白质的电子转移速率的数据，以及理论的力量来预测的隧道电子在生物基质中穿过的路径;此外，他们强调了氢键在生物电子转移过程中发挥的重要作用。
Three supramolecular bischromophoric systems featuring zinc(II) and iron(III) porphyrins have been synthesized to evaluate the relative magnitudes of electronic coupling provided by hydrogen, sigma, and pi bonds. Laser flash excitation generates the highly reducing singlet excited state of the (porphinato)zinc chromophore that can subsequently be electron transfer quenched by the (porphinato)iron(III) chloride moiety. Measurement of the photoinduced electron transfer rate constants enables a direct comparison of how well these three types of chemical interactions facilitate electron tunneling, In contrast to generally accepted theory, electronic coupling modulated by a hydrogen-bond interface is greater than that provided by an analogous interface composed entirely of carbon-carbon a bonds. These results bear considerably on the analysis of through-protein electron transfer rate data as well as on the power of theory to predict the path traversed by the tunneling electron in a biological matrix; moreover, they underscore the cardinal role played by hydrogen bonds in biological electron transfer processes.