Modeling the Active Sites in Metalloenzymes 5. The Heterolytic Bond Cleavage of H2 in the [NiFe] Hydrogenase of Desulfovibrio gigas by a Nucleophilic Addition Mechanism
Citations Over TimeTop 10% of 2001 papers
Abstract
The H(2) activation catalyzed by an Fe(II)-Ni(III) model of the [NiFe] hydrogenase of Desulfovibrio gigas has been investigated by density functional theory (DFT/B3LYP) calculations on the neutral and anionic active site complexes, [(CO)(CN)(2)Fe(mu-SH)(2)Ni(SH)(SH(2))](0) and [(CO)(CN)(2)Fe(mu-SH)(2)Ni(SH)(2)](-). The results suggest that the reaction proceeds by a nucleophilic addition mechanism that cleaves the H-H bond heterolytically. The terminal cysteine residue Cys530 in the [NiFe] hydrogenase active site of the D. gigas enzyme plays a crucial role in the catalytic process by accepting the proton. The active site is constructed to provide access by this cysteine residue, and this role explains the change in activity observed when this cysteine is replaced by a selenocysteine. Furthermore, the optimized geometry of the transition state in the model bears a striking resemblance to the geometry of the active site as determined by X-ray crystallography.
Related Papers
- → The direct role of selenocysteine in [NiFeSe] hydrogenase maturation and catalysis(2017)94 cited
- → Molecular dynamics and experimental investigation of H2 and O2 diffusion in [Fe]-hydrogenase(2005)107 cited
- → Redox state-dependent changes in the crystal structure of [NiFeSe] hydrogenase from Desulfovibrio vulgaris Hildenborough(2013)40 cited
- → Characterization of the [NiFeSe] hydrogenase from Desulfovibrio vulgaris Hildenborough(2018)18 cited
- → pH Dependent Photodeprotection of Formaldehyde: Homolytic C–C Scission in Acidic Aqueous Solution versus Heterolytic C–C Scission in Basic Aqueous Solution(2017)1 cited