Extremophiles

, Volume 12, Issue 1, pp 29–38

Reconsideration of an early dogma, saying “there is no evidence for disulfide bonds in proteins from archaea”

Review

DOI: 10.1007/s00792-007-0076-z

Cite this article as:
Ladenstein, R. & Ren, B. Extremophiles (2008) 12: 29. doi:10.1007/s00792-007-0076-z

Abstract

Stability and function of a large number of proteins are crucially dependent on the presence of disulfide bonds. Recent genome analysis has pointed out an important role of disulfide bonds for the structural stabilization of intracellular proteins from hyperthermophilic archaea and bacteria. These findings contradict the conventional view that disulfide bonds are rare in those proteins. A specific protein, known as protein disulfide oxidoreductase (PDO) is recognized as a potential key enzyme in intracellular disulfide-shuffling in hyperthermophiles. The structure of this protein consists of two combined thioredoxin-related units which together, in tandem-like manner, form a closed protein domain. Each of these units contains a distinct CXXC active site motif. Both sites seem to have different redox properties. A relation to eukaryotic protein disulfide isomerase is suggested by the observed structural and functional characteristics of the protein. Enzymological studies have revealed that both, the archaeal and bacterial forms of this protein show oxidative and reductive activity and are able to isomerize protein disulfides. The variety of active site disulfides found in PDO’s from hyperthermophiles is puzzling. It is assumed, that PDO enzymes in hyperthermophilic archaea and bacteria may be part of a complex system involved in the maintenance of protein disulfide bonds.

Keywords

ArchaeaHyperthermophilesProtein disulfide isomeraseProtein disulfide oxidoreductaseRedox potentialThermostabilityThioredoxin

Abbreviations

PDI

Protein disulfide isomerase

PDO

Protein disulfide oxido-reductase

DTT

Dithiothreitol

GSH

Reduced glutathione

GSSG

Oxidized glutathione

Copyright information

© Springer 2007

Authors and Affiliations

  1. 1.Center of Structural BiochemistryKarolinska Institutet NOVUMHuddingeSweden