Evidence for the formation of a Mo-H intermediate in the catalytic cycle of formate dehydrogenase

TY - JOUR

T1 - Evidence for the formation of a Mo-H intermediate in the catalytic cycle of formate dehydrogenase

AU - Tiberti, Matteo

AU - Papaleo, Elena

AU - Russo, Nino

AU - De Gioia, Luca

AU - Zampella, Giuseppe

PY - 2012/8/6

Y1 - 2012/8/6

N2 - DFT/BP86/TZVP and DFT/B3LYP/TZVP have been used to investigate systematically the reaction pathways associated with the H-transfer step, which is the rate-determining step of the reaction HCOO(-) ⇄ CO(2) + H(+) + 2e(-), as catalyzed by metalloenzyme formate dehydrogenase (FDH). Actually, the energetics associated with the transfer from formate to all H (proton or hydride) acceptors that are present within the FDH active site have been sampled. This study points to a viable intimate mechanism in which the metal center mediates H transfer from formate to the final acceptor, i.e. a selenocysteine residue. The Mo-based reaction pathway, consisting of a β-H elimination to metal with concerted decarboxylation, turned out to be favored over previously proposed routes in which proton transfer occurs directly from HCOO(-) to selenocysteine. The proposed reaction pathway is reminiscent of the key step of metal-based catalysis of the water-gas shift reaction.

AB - DFT/BP86/TZVP and DFT/B3LYP/TZVP have been used to investigate systematically the reaction pathways associated with the H-transfer step, which is the rate-determining step of the reaction HCOO(-) ⇄ CO(2) + H(+) + 2e(-), as catalyzed by metalloenzyme formate dehydrogenase (FDH). Actually, the energetics associated with the transfer from formate to all H (proton or hydride) acceptors that are present within the FDH active site have been sampled. This study points to a viable intimate mechanism in which the metal center mediates H transfer from formate to the final acceptor, i.e. a selenocysteine residue. The Mo-based reaction pathway, consisting of a β-H elimination to metal with concerted decarboxylation, turned out to be favored over previously proposed routes in which proton transfer occurs directly from HCOO(-) to selenocysteine. The proposed reaction pathway is reminiscent of the key step of metal-based catalysis of the water-gas shift reaction.

KW - Bacterial Proteins

KW - Binding Sites

KW - Biocatalysis

KW - Crystallography, X-Ray

KW - Escherichia coli

KW - Formate Dehydrogenases

KW - Formates

KW - Kinetics

KW - Metalloproteins

KW - Models, Molecular

KW - Molybdenum

KW - Protons

KW - Quantum Theory

KW - Selenocysteine

KW - Static Electricity

KW - Thermodynamics

U2 - 10.1021/ic300863d

DO - 10.1021/ic300863d

M3 - Journal article

C2 - 22800191

SN - 0020-1669

VL - 51

SP - 8331

EP - 8339

JO - Inorganic Chemistry

JF - Inorganic Chemistry

IS - 15

ER -