Inactivation of [FeFe]-hydrogenase by O2. Thermodynamics and frontier molecular orbitals analyses

O2 reduction and O2-induced damage at the active site of FeFe hydrogenase

FeFe hydrogenases are the most efficient H2 producing enzymes, but inactivation by O2 is an obstacle to using them in biotechnological devices. Here we combine electrochemistry, sitedirected mutagenesis, molecular dynamics and quantum chemical calculations to uncover the molecular mechanism of O2 diffusion within the enzyme and its reactions at the active site. We find that the partial reversib...

Synthetic [FeFe] Hydrogenase Active Site Model Complexes

The oxidative inactivation of FeFe hydrogenase reveals the flexibility of the H-cluster.

Nature is a valuable source of inspiration in the design of catalysts, and various approaches are used to elucidate the mechanism of hydrogenases, the enzymes that oxidize or produce H2. In FeFe hydrogenases, H2 oxidation occurs at the H-cluster, and catalysis involves H2 binding on the vacant coordination site of an iron centre. Here, we show that the reversible oxidative inactivation of this ...

Frontier Hyhrid Orbitals . I . Principles *

The purpose of the present paper is to describe a method, in quantitative sense, of discussing the isolobal analogy of fragments (or molecules) proposed by Hoffmann. The »Frontier Hybrid Orbitals (FHO)« are used to represent the directional, fronti er orbitals of the central atom, which have the same meaning as the »lobes« involved in the concept of isolobal analogy. The calculatio n of Frontie...

Frontier Hybrid Orbitals . II . Applications

In this paper, the frontier hybrid orbitals (FBO's) of a series of octahedral ML5 fragments are used to discuss the electronic structure and the chemical bond of these fragments and the molecules built of these ML5 fragments. The bond orbitals which are chosen as the linear combination of the frontier hybrid orbitals . of fragments are calculated and explain the electronic structure and propert...