Open AccessThe Archaeon Methanosarcina acetivorans Contains a Protein Disulfide Reductase with an Iron-Sulfur Cluster
Author(s) -
Daniel J. Lessner,
James G. Ferry
Publication year - 2007
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.00891-07
Subject(s) - biochemistry , reductase , archaea , biology , sulfite reductase , gene cluster , thermophile , methanosarcina , ferredoxin , trimer , enzyme , gene , stereochemistry , chemistry , dimer , organic chemistry
Methanosarcina acetivorans , a strictly anaerobic methane-producing species belonging to the domainArchaea , contains a gene cluster annotated with homologs encoding oxidative stress proteins. One of the genes (MA3736) is annotated as a gene encoding an uncharacterized carboxymuconolactone decarboxylase, an enzyme required for aerobic growth with aromatic compounds by species in the domainBacteria . Methane-producing species are not known to utilize aromatic compounds, suggesting that MA3736 is incorrectly annotated. The product of MA3736, overproduced inEscherichia coli , had protein disulfide reductase activity dependent on a C67 XXC70 motif not found in carboxymuconolactone decarboxylase. We propose that MA3736 be renamedmdrA (m ethanosarcinad isulfider eductase). 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 that 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.