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This content will become publicly available on August 29, 2018

Title: Activation Thermodynamics and H/D Kinetic Isotope Effect of the H ox to H red H + Transition in [FeFe] Hydrogenase

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 in this paper 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 ox→H redH + reduction step measured by Fourier-transform infrared spectroscopy showed an enthalpy of activation of 19 kJ mol -1 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 ox→H redH + step of catalytic proton reduction in CaI proceeds by a proton-dependent process.
Authors:
 [1] ;  [2] ;  [1] ; ORCiD logo [1] ;  [2] ;  [1] ; ORCiD logo [2] ; ORCiD logo [1]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States). Biosciences Center
  2. Univ. of Colorado, Boulder, CO (United States). Dept. of Chemistry and Biochemistry
Publication Date:
Report Number(s):
NREL/JA-2700-68424
Journal ID: ISSN 0002-7863; TRN: US1702385
Grant/Contract Number:
AC36-08GO28308; SC0010334
Type:
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 139; Journal Issue: 37; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; thermodynamics; H2 catalysis; hydrogenase
OSTI Identifier:
1394746