Abstract:Background: Sulfur carrier proteins Rhd_2599, TusA, and DsrE2 occur in many sulfur oxidizing prokaryotes. Results: Rhd_2599, TusA, and possibly DsrE2 are involved in cytoplasmic sulfur trafficking during dissimilatory sulfur oxidation. Conclusion: Sulfur transfer from persulfide intermediates to dissimilatory sulfite reductase involves Rhd_2599, TusA, and possibly DsrE2. Significance: Proteins involved in dissimilatory sulfur oxidation have been identified.
“…The protein from A. vinosum (Alvin_2599) is a soluble monomer and catalyzes sulfur transfer from thiosulfate or GSSH to cyanide in vitro . Mass spectrometry verified the transfer of sulfane sulfur from both substrates to the conserved active site of cysteine but not to a second only partly conserved cysteine . Most importantly, TusA was clearly established as a protein accepting sulfane sulfur from the A. vinosum rhodanese.…”
Section: The Input Modulesmentioning
confidence: 90%
“…The A. vinosum protein (Alvin_2601)‐encoded downstream of the rhd‐tusA genes falls into group DsrE2A with the active site cysteine present as the second in a conserved Cys‐X 9 ‐Cys motif. Recombinant A. vinosum DsrE2A is an experimentally established membrane protein with two predicted transmembrane helices arranged such that the carboxy‐terminal part of the protein carrying one strictly conserved and two further cysteine residues is located in the cytoplasm . The same topology is predicted for the DsrE2A proteins encoded in all members of the Chromatiaceae and Acidithiobacillaceae families listed in ref.…”
Section: The Input Modulesmentioning
confidence: 95%
“…TusA alone is incapable of mobilizing sulfur from thiosulfate or low-molecular-weight organic persulfides like glutathione persulfide (GSSH; ref. 4).…”
Section: The Tusa Proteinmentioning
confidence: 99%
“…In several sulfur oxidizers including Acidithiobacillus ferrooxidans, Metallosphaera sedula, and the purple sulfur bacterium Allochromatium vinosum, relative mRNA levels for tusA were significantly higher under sulfur-oxidizing conditions than in the absence of reduced sulfur compounds (22,(31)(32)(33). An A. vinosum strain deficient of the rhd-tusA-dsrE2 genes was impaired in its ability to degrade zero-valent sulfur formed during the oxidation of sulfide and thiosulfate (4). The eminently important role of TusA is further highlighted by the finding that TusA is among the most abundant proteins in A. vinosum cells grown photolithoautotrophically on reduced sulfur compounds ( Fig.…”
Section: The Tusa Proteinmentioning
confidence: 99%
“…The rhd-tusA-dsrE2 genes are cotranscribed in A. vinosum (4). In this as well as in all other cases studied, the genes follow the same pattern of transcription as observed for the established or putative cytoplasmic sulfane sulfur-oxidizing proteins (i.e., the Dsr or Hdr-like system) and other proteins involved in oxidative sulfur metabolism such as sulfur globule proteins or the enzymes of the two different cytoplasmic sulfite oxidation pathways in A. vinosum (4,22,32,33,35).…”
Persulfide groups are chemically versatile and participate in a wide array of biochemical pathways. Although it is well documented that persulfurated proteins supply a number of important and elaborate biosynthetic pathways with sulfane sulfur, it is far less acknowledged that the enzymatic generation of persulfidic sulfur, the successive transfer of sulfur as a persulfide between multiple proteins, and the oxidation of sulfane sulfur in protein-bound form are also essential steps during dissimilatory sulfur oxidation in bacteria and archaea. Here, the currently available information on sulfur trafficking in sulfur oxidizing prokaryotes is reviewed, and the idea is discussed that sulfur is always presented to cytoplasmic oxidizing enzymes in a protein-bound form, thus preventing the occurrence of free sulfide inside of the prokaryotic cell. Thus, sulfur trafficking emerges as a central element in sulfuroxidizing pathways, and TusA homologous proteins appear to be central and common elements in these processes. V C 2015 IUBMB Life, 67(4): [268][269][270][271][272][273][274] 2015
“…The protein from A. vinosum (Alvin_2599) is a soluble monomer and catalyzes sulfur transfer from thiosulfate or GSSH to cyanide in vitro . Mass spectrometry verified the transfer of sulfane sulfur from both substrates to the conserved active site of cysteine but not to a second only partly conserved cysteine . Most importantly, TusA was clearly established as a protein accepting sulfane sulfur from the A. vinosum rhodanese.…”
Section: The Input Modulesmentioning
confidence: 90%
“…The A. vinosum protein (Alvin_2601)‐encoded downstream of the rhd‐tusA genes falls into group DsrE2A with the active site cysteine present as the second in a conserved Cys‐X 9 ‐Cys motif. Recombinant A. vinosum DsrE2A is an experimentally established membrane protein with two predicted transmembrane helices arranged such that the carboxy‐terminal part of the protein carrying one strictly conserved and two further cysteine residues is located in the cytoplasm . The same topology is predicted for the DsrE2A proteins encoded in all members of the Chromatiaceae and Acidithiobacillaceae families listed in ref.…”
Section: The Input Modulesmentioning
confidence: 95%
“…TusA alone is incapable of mobilizing sulfur from thiosulfate or low-molecular-weight organic persulfides like glutathione persulfide (GSSH; ref. 4).…”
Section: The Tusa Proteinmentioning
confidence: 99%
“…In several sulfur oxidizers including Acidithiobacillus ferrooxidans, Metallosphaera sedula, and the purple sulfur bacterium Allochromatium vinosum, relative mRNA levels for tusA were significantly higher under sulfur-oxidizing conditions than in the absence of reduced sulfur compounds (22,(31)(32)(33). An A. vinosum strain deficient of the rhd-tusA-dsrE2 genes was impaired in its ability to degrade zero-valent sulfur formed during the oxidation of sulfide and thiosulfate (4). The eminently important role of TusA is further highlighted by the finding that TusA is among the most abundant proteins in A. vinosum cells grown photolithoautotrophically on reduced sulfur compounds ( Fig.…”
Section: The Tusa Proteinmentioning
confidence: 99%
“…The rhd-tusA-dsrE2 genes are cotranscribed in A. vinosum (4). In this as well as in all other cases studied, the genes follow the same pattern of transcription as observed for the established or putative cytoplasmic sulfane sulfur-oxidizing proteins (i.e., the Dsr or Hdr-like system) and other proteins involved in oxidative sulfur metabolism such as sulfur globule proteins or the enzymes of the two different cytoplasmic sulfite oxidation pathways in A. vinosum (4,22,32,33,35).…”
Persulfide groups are chemically versatile and participate in a wide array of biochemical pathways. Although it is well documented that persulfurated proteins supply a number of important and elaborate biosynthetic pathways with sulfane sulfur, it is far less acknowledged that the enzymatic generation of persulfidic sulfur, the successive transfer of sulfur as a persulfide between multiple proteins, and the oxidation of sulfane sulfur in protein-bound form are also essential steps during dissimilatory sulfur oxidation in bacteria and archaea. Here, the currently available information on sulfur trafficking in sulfur oxidizing prokaryotes is reviewed, and the idea is discussed that sulfur is always presented to cytoplasmic oxidizing enzymes in a protein-bound form, thus preventing the occurrence of free sulfide inside of the prokaryotic cell. Thus, sulfur trafficking emerges as a central element in sulfuroxidizing pathways, and TusA homologous proteins appear to be central and common elements in these processes. V C 2015 IUBMB Life, 67(4): [268][269][270][271][272][273][274] 2015
A heterodisulfide reductase‐like complex (sHdr) and novel lipoate‐binding proteins (LbpAs) are central players of a wide‐spread pathway of dissimilatory sulfur oxidation. Bioinformatic analysis demonstrate that the cytoplasmic sHdr–LbpA systems are always accompanied by sets of sulfur transferases (DsrE proteins, TusA, and rhodaneses). The exact composition of these sets may vary depending on the organism and sHdr system type. To enable generalizations, we studied model sulfur oxidizers from distant bacterial phyla, that is, Aquificota and Pseudomonadota. DsrE3C of the chemoorganotrophic Alphaproteobacterium Hyphomicrobium denitrificans and DsrE3B from the Gammaproteobacteria Thioalkalivibrio sp. K90mix, an obligate chemolithotroph, and Thiorhodospira sibirica, an obligate photolithotroph, are homotrimers that donate sulfur to TusA. Additionally, the hyphomicrobial rhodanese‐like protein Rhd442 exchanges sulfur with both TusA and DsrE3C. The latter is essential for sulfur oxidation in Hm. denitrificans. TusA from Aquifex aeolicus (AqTusA) interacts physiologically with AqDsrE, AqLbpA, and AqsHdr proteins. This is particularly significant as it establishes a direct link between sulfur transferases and the sHdr–LbpA complex that oxidizes sulfane sulfur to sulfite. In vivo, it is unlikely that there is a strict unidirectional transfer between the sulfur‐binding enzymes studied. Rather, the sulfur transferases form a network, each with a pool of bound sulfur. Sulfur flux can then be shifted in one direction or the other depending on metabolic requirements. A single pair of sulfur‐binding proteins with a preferred transfer direction, such as a DsrE3‐type protein towards TusA, may be sufficient to push sulfur into the sink where it is further metabolized or needed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.