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Characterization of a unique [FeS] cluster in the electron transfer chain of the oxygen tolerant [NiFe] hydrogenase from Aquifex aeolicus
TLDR
It is suggested that the (1 + /2+) redox couple serves the classical electron transfer reaction, whereas the superoxidation step is associated with a redox switch against oxidative stress. Expand
Evolution and diversification of Group 1 [NiFe] hydrogenases. Is there a phylogenetic marker for O(2)-tolerance?
TLDR
Genomic screening and phylogenetic tree reconstruction revealed that 6C hydrogenases form a monophyletic clade and are unexpectedly widespread among bacteria, and several other well-defined clades are observed, which indicate early diversification of the enzyme into different subfamilies. Expand
Substrate-triggered addition of dioxygen to the diferrous cofactor of aldehyde-deformylating oxygenase to form a diferric-peroxide intermediate.
TLDR
The results represent the most definitive evidence to date that ADO can use a diiron cofactor (rather than a homo- or heterodinuclear cluster involving another transition metal) and provide support for a mechanism involving attack on the carbonyl of the bound substrate by the reduced O2 moiety to form a Fe2(III/III) complex with a bound peroxide. Expand
Mössbauer spectroscopy of Fe/S proteins.
TLDR
Fe Mössbauer spectroscopy is a technique that provides information about the chemical nature of all chemically distinct Fe species contained in a sample, such as Fe oxidation and spin state, nuclearity of a cluster with more than one metal ion, electron spin ground state of the cluster, and delocalization properties in mixed-valent clusters. Expand
Membrane-bound hydrogenase I from the hyperthermophilic bacterium Aquifex aeolicus: enzyme activation, redox intermediates and oxygen tolerance.
TLDR
The membrane-bound hydrogenase (Hase I) of the hyperthermophilic bacterium Aquifex aeolicus belongs to an intriguing class of redox enzymes that show enhanced thermostability and oxygen tolerance and is presented in relation to the proposed models of oxygen tolerance. Expand
Evidence for a Catalytically and Kinetically Competent Enzyme–Substrate Cross-Linked Intermediate in Catalysis by Lipoyl Synthase
TLDR
Generation of the cross-linked species with a small, unlabeled (N6-octanoyl)-lysyl-containing peptide substrate allowed demonstration of both its chemical and kinetic competence, providing strong evidence that it is an intermediate in the LS reaction. Expand
Electronic structure of the quinone radical anion A1*- of photosystem I investigated by advanced pulse EPR and ENDOR techniques.
TLDR
This work characterized the electron spin density distribution of A1*- with the aim of understanding the influence of the protein surrounding on it and concluded that the single H-bond present in both the radical pair P700*+A1-- and the photoaccumulated radical anion A1- is the crucial factor that governs the electronic structure of A 1*-. Expand
Rapid Reduction of the Diferric-Peroxyhemiacetal Intermediate in Aldehyde-Deformylating Oxygenase by a Cyanobacterial Ferredoxin: Evidence for a Free-Radical Mechanism.
TLDR
The detection of these radicals under turnover conditions provides the most direct evidence to date for a free-radical mechanism in aldehyde-deformylating oxygenase, exposing an inefficiency of the enzyme in processing its radical intermediate. Expand
Efficient delivery of long-chain fatty aldehydes from the Nostoc punctiforme acyl-acyl carrier protein reductase to its cognate aldehyde-deformylating oxygenase.
TLDR
The results suggest that the interaction between AAR and ADO facilitates either direct transfer of the aldehyde product of AAR to ADO or formation of the analsis product in a microenvironment allowing for its efficient uptake by ADO. Expand
Organophosphonate-degrading PhnZ reveals an emerging family of HD domain mixed-valent diiron oxygenases
TLDR
The results demonstrate that the catalytic repertoire of the HD superfamily extends well beyond phosphohydrolysis and suggest that the mechanism used by MIOX and PhnZ may be a common strategy for oxidative C-X bond cleavage. Expand
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