Electrochemical Kinetics Support a Second Coordination Sphere Mechanism in Metal‐Based Formate Dehydrogenase

Marta Meneghello (1) , Alexandre Uzel (1) , Marianne Broc (2) , Rita R Manuel , Axel Magalon (2, 3) , Christophe Léger (1) , Inês A C Pereira , Anne Walburger (2) , Vincent Fourmond (1)

1 BIP - Bioénergétique et Ingénierie des Protéines
2 LCB - Laboratoire de chimie bactérienne
3 IMM - Institut de Microbiologie de la Méditerranée

Metal-based formate dehydrogenases are molybdenum or tungsten-dependent enzymes that catalyze the interconversion between formate and CO 2. According to the current consensus, the metal ion of the catalytic center in its active form is coordinated by 6 S (or 5 S and 1 Se) atoms, leaving no free coordination sites to which formate could bind to the metal. Some authors have proposed that one of the active site ligands decoordinates during turnover to allow formate binding. Another proposal is that the oxidation of formate takes place in the second coordination sphere of the metal. Here, we have used electrochemical steady-state kinetics to elucidate the order of the steps in the catalytic cycle of two formate dehydrogenases. Our results strongly support the "second coordination sphere" hypothesis.

Mots clés: Metalloenzymes Enzyme catalysis Electrochemistry Mo/W formate dehydrogenase Second coordination sphere; Metalloenzymes; Enzyme catalysis; Electrochemistry; Mo/W formate dehydrogenase; Second coordination sphere

Domaines: Chimie de coordination; Chimie inorganique; Biochimie [q-bio.BM]

Marta Meneghello, Alexandre Uzel, Marianne Broc, Rita R Manuel, Axel Magalon, et al.. Electrochemical Kinetics Support a Second Coordination Sphere Mechanism in Metal‐Based Formate Dehydrogenase. Angewandte Chemie International Edition, 2023, 62 (6), ⟨10.1002/anie.202212224⟩. ⟨hal-03965660⟩