Open AccessQuantitative proteomics of C hlorobaculum tepidum : insights into the sulfur metabolism of a phototrophic green sulfur bacterium
Author(s) -
Falkenby Lasse G.,
Szymanska Monika,
Holkenbrink Carina,
Habicht Kirsten S.,
Andersen Jens S.,
Miller Mette,
Frigaard NielsUlrik
Publication year - 2011
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2011.02370.x
Subject(s) - thiosulfate , sulfur , sulfur metabolism , biochemistry , sulfide , sulfite reductase , sulfite , periplasmic space , rhodanese , biology , bacteria , chemistry , enzyme , escherichia coli , reductase , gene , genetics , organic chemistry
C hlorobaculum ( C ba .) tepidum is a green sulfur bacterium that oxidizes sulfide, elemental sulfur, and thiosulfate for photosynthetic growth. To gain insight into the sulfur metabolism, the proteome of C ba. tepidum cells sampled under different growth conditions has been quantified using a rapid gel‐free, filter‐aided sample preparation ( FASP ) protocol with an in‐solution isotopic labeling strategy. Among the 2245 proteins predicted from the C ba. tepidum genome, approximately 970 proteins were detected in unlabeled samples, whereas approximately 630–640 proteins were detected in labeled samples comparing two different growth conditions. Wild‐type cells growing on thiosulfate had an increased abundance of periplasmic cytochrome c ‐555 and proteins of the periplasmic thiosulfate‐oxidizing SOX enzyme system when compared with cells growing on sulfide. A dsrM mutant of C ba. tepidum , which lacks the dissimilatory sulfite reductase D sr M protein and therefore is unable to oxidize sulfur globules to sulfite, was also investigated. When compared with wild type, the dsrM cells exhibited an increased abundance of DSR enzymes involved in the initial steps of sulfur globule oxidation ( D sr ABCL ) and a decreased abundance of enzymes putatively involved in sulfite oxidation ( S at‐ A pr AB ‐ Q mo ABC ). The results show that C ba. tepidum regulates the cellular levels of enzymes involved in sulfur metabolism and other electron‐transferring processes in response to the availability of reduced sulfur compounds.