Trigger mechanism for the catalytic hydrogen activation by monoiron (iron-sulfur cluster-free) hydrogenase.

abstract

• A fully optimized model for the resting state of the active site of the third type of phylogenetically unrelated (monoiron) hydrogenase, iron-sulfur cluster-free hydrogenase (Hmd), was constructed based on density functional calculations. This resting state structure shows good agreement with the experimental IR spectra. The calculations predict that the barrier for H2 cleavage in the presence of MPT+ is 18 kcal/mol lower than that in the absence of MPT+, a result that explains why the isotopic H2/D2O exchange catalyzed by Hmd is strictly dependent on the presence of MPT+. This difference is a result of the MPT+ triggering the pyridone to provide electron density to allow the Fe to take a proton while transferring a hydride to the MPT+. These active site models and catalytic mechanism are useful in understanding this hydrogen activation for the design of novel hydrogenation catalysts and for low cost, high efficiency hydrogen generation.

authors

• Hall, Michael

published proceedings

• J Am Chem Soc

author list (cited authors)

• Yang, X., & Hall, M. B.

citation count

• 55

complete list of authors

• Yang, Xinzheng||Hall, Michael B

publication date

• October 2008

publisher

• American Chemical Society (ACS)  Publisher

published in

• Journal of the American Chemical Society  Journal

keywords

• Binding Sites
• Catalysis
• Computer Simulation
• Ferric Compounds
• Hydrogen
• Hydrogen-Ion Concentration
• Models, Biological
• Molecular Conformation
• Oxidoreductases Acting On Ch-nh Group Donors
• Pterins
• Stereoisomerism

PubMed Central ID

• 18826317

Digital Object Identifier (DOI)

• 10.1021/ja804364p

start page

• 14036

end page

• 14037

volume

• 130

issue

• 43

URL

• http://dx.doi.org/10.1021/ja804364p

user-defined tag

• 7 Affordable and Clean Energy