This Article Full Text (PDF) Other Versions of this Article: JB.00891-07v1 189/20/7475    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Lessner, D. J. Articles by Ferry, J. G. Search for Related Content PubMed PubMed Citation Articles by Lessner, D. J. Articles by Ferry, J. G.

 Previous Article  |  Next Article 

J. Bacteriol. doi:10.1128/JB.00891-07
Copyright (c) 2007, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

The Archaeon Methanosarcina acetivorans Contains a Protein Disulfide Reductase with an Iron-Sulfur Cluster

Department of Biochemistry and Molecular Biology and Penn State Astrobiology Research Center, 205 South Frear Laboratory, Pennsylvania State University, University Park, PA 16802

^* To whom correspondence should be addressed. Email: jgf3{at}psu.edu.

	Abstract

Methanosarcina acetivorans, a strictly anaerobic methane-producing species from the Archaea domain, contains a gene cluster annotated with homologs encoding oxidative stress proteins. One of the genes (MA3736) is annotated as encoding an uncharacterized carboxymuconolactone decarboxylase, an enzyme required for aerobic growth with aromatic compounds by species in the Bacteria domain. Methane-producing species are not known to utilize aromatic compounds, suggesting MA3736 is incorrectly annotated. The product of MA3736, overproduced in Escherichia coli, had protein disulfide reductase activity dependent on a C₆₇XXC₇₀ motif not found in carboxymuconolactone decarboxylase. We propose that MA3736 be renamed mdrA (methanosarcina disulfide reductase). Further, unlike carboxymuconolactone decarboxylase MdrA contained an Fe-S cluster. Binding of the Fe-S cluster was dependent on essential cysteines C₆₇ and C₇₀, while cysteines C₃₉ and C₁₀₇ were not required. Loss of the Fe-S cluster resulted in conversion of MdrA from an inactive hexamer to a trimer with protein disulfide reductase activity. The data suggest MdrA is the prototype of a previously unrecognized protein disulfide reductase family which contains an intermolecular Fe-S cluster that controls oligomerization as a mechanism to regulate protein disulfide reductase activity.