In vivo requirement for glutaredoxins and thioredoxins in the reduction of the ribonucleotide reductases of Escherichia coli

Escherichia coli expresses three types of ribonucleotide reductases (RNRs) that utilize the redox chemistry of cysteine to catalyze the reduction of ribonucleotides. Upon reduction, the cysteines form a disulfide bond and must be reduced. The authors present in vivo studies that shed light on the me...

Full description

Saved in:
Bibliographic Details
Published in:Antioxidants & redox signaling Vol. 8; no. 5-6; p. 735
Main Authors: Gon, Stéphanie, Faulkner, Melinda J, Beckwith, Jon
Format: Journal Article
Language:English
Published: United States 01.05.2006
Subjects:
Anaerobiosis
Escherichia coli - enzymology
Escherichia coli - physiology
Escherichia coli Proteins - genetics
Escherichia coli Proteins - metabolism
Glutaredoxins
Isoenzymes - genetics
Isoenzymes - metabolism
Oxidation-Reduction
Oxidoreductases - genetics
Oxidoreductases - metabolism
Ribonucleotide Reductases - genetics
Ribonucleotide Reductases - metabolism
Thioredoxins - genetics
Thioredoxins - metabolism
ISSN:1523-0864
Online Access:Get more information
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Escherichia coli expresses three types of ribonucleotide reductases (RNRs) that utilize the redox chemistry of cysteine to catalyze the reduction of ribonucleotides. Upon reduction, the cysteines form a disulfide bond and must be reduced. The authors present in vivo studies that shed light on the mechanism by which these enzymes are regenerated. The class Ia enzyme, NrdAB, can be reduced by either the thioredoxins 1 and 2 or by glutaredoxin 1. The class Ib enzyme, NrdEF, is reduced in vivo by a dedicated glutaredoxin-like protein, NrdH. Despite its similarities to glutaredoxins, this protein is itself reduced by thioredoxin reductase in vivo. However, in the absence of thioredoxin reductase and NrdH, glutaredoxin 1 can partially replace NrdH. Despite their similar structures, the NrdEF and NrdAB RNRs differ in their abilities to function under low oxygen conditions. With only traces of oxygen present, NrdAB can allow some growth in the absence of the anaerobic enzyme NrdDG. NrdEF cannot. Furthermore, in anaerobiosis, E. coli is dependent for growth on class III RNR, NrdDG, and on having at least one of the two reductive systems, thioredoxin reductase or glutathione reductase. These findings indicate a role for these enzymes either for NrdDG reactivation or some other essential anaerobic process.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:1523-0864
DOI:10.1089/ars.2006.8.735