[FeFe]氢化酶中 H 到 HH 转变的活化热力学和 H/D 动力学同位素效应。
Activation Thermodynamics and H/D Kinetic Isotope Effect of the H to HH Transition in [FeFe] Hydrogenase.
机构信息
Biosciences Center, National Renewable Energy Laboratory , Golden, Colorado 80401, United States.
Department of Chemistry and Biochemistry, University of Colorado Boulder , Boulder, Colorado 80309, United States.
出版信息
J Am Chem Soc. 2017 Sep 20;139(37):12879-12882. doi: 10.1021/jacs.7b04216. Epub 2017 Sep 6.
Molecular complexes between CdSe nanocrystals and Clostridium acetobutylicum [FeFe] hydrogenase I (CaI) enabled light-driven control of electron transfer for spectroscopic detection of redox intermediates during catalytic proton reduction. Here we address the route of electron transfer from CdSe→CaI and activation thermodynamics of the initial step of proton reduction in CaI. The electron paramagnetic spectroscopy of illuminated CdSe:CaI showed how the CaI accessory FeS cluster chain (F-clusters) functions in electron transfer with CdSe. The H→HH reduction step measured by Fourier-transform infrared spectroscopy showed an enthalpy of activation of 19 kJ mol and a ∼2.5-fold kinetic isotope effect. Overall, these results support electron injection from CdSe into CaI involving F-clusters, and that the H→HH step of catalytic proton reduction in CaI proceeds by a proton-dependent process.
CdSe 纳米晶体与梭菌属丙酮丁醇梭菌[FeFe]氢化酶 I（CaI）之间的分子复合物能够实现光驱动控制电子转移，用于在催化质子还原过程中对氧化还原中间体进行光谱检测。在这里，我们研究了电子从 CdSe→CaI 的转移途径以及 CaI 中质子还原初始步骤的活化热力学。光照下的 CdSe：CaI 的电子顺磁共振光谱显示了 CaI 辅助的 FeS 簇链（F 簇）如何与 CdSe 进行电子转移。傅里叶变换红外光谱测量的 H→HH 还原步骤显示活化焓为 19 kJ mol，动力学同位素效应约为 2.5 倍。总的来说，这些结果支持电子从 CdSe 注入到涉及 F 簇的 CaI，并且 CaI 中催化质子还原的 H→HH 步骤通过依赖质子的过程进行。
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