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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

Ratzloff, Michael W., Wilker, Molly B., Mulder, David W., Lubner, Carolyn E., Hamby, Hayden, Brown, Katherine A., Dukovic, Gordana, and King, Paul W.. Activation Thermodynamics and H/D Kinetic Isotope Effect of the Hox to Hred H+ Transition in [FeFe] Hydrogenase. United States: N. p., Web. doi:10.1021/jacs.7b04216.
Ratzloff, Michael W., Wilker, Molly B., Mulder, David W., Lubner, Carolyn E., Hamby, Hayden, Brown, Katherine A., Dukovic, Gordana, & King, Paul W.. Activation Thermodynamics and H/D Kinetic Isotope Effect of the Hox to Hred H+ Transition in [FeFe] Hydrogenase. United States. doi:10.1021/jacs.7b04216.
Ratzloff, Michael W., Wilker, Molly B., Mulder, David W., Lubner, Carolyn E., Hamby, Hayden, Brown, Katherine A., Dukovic, Gordana, and King, Paul W.. 2017. "Activation Thermodynamics and H/D Kinetic Isotope Effect of the Hox to Hred H+ Transition in [FeFe] Hydrogenase". United States. doi:10.1021/jacs.7b04216. https://www.osti.gov/servlets/purl/1394746.
@article{osti_1394746,
title = {Activation Thermodynamics and H/D Kinetic Isotope Effect of the Hox to Hred H+ Transition in [FeFe] Hydrogenase},
author = {Ratzloff, Michael W. and Wilker, Molly B. and Mulder, David W. and Lubner, Carolyn E. and Hamby, Hayden and Brown, Katherine A. and Dukovic, Gordana and King, Paul W.},
abstractNote = {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 Hox→HredH+ 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 Hox→HredH+ step of catalytic proton reduction in CaI proceeds by a proton-dependent process.},
doi = {10.1021/jacs.7b04216},
journal = {Journal of the American Chemical Society},
number = 37,
volume = 139,
place = {United States},
year = {2017},
month = {8}
}