KEGG   PATHWAY: map00920
Entry
map00920                    Pathway                                
Name
Sulfur metabolism
Description
Sulfur is an essential element for life and the metabolism of organic sulfur compounds plays an important role in the global sulfur cycle. Sulfur occurs in various oxidation states ranging from +6 in sulfate to -2 in sulfide (H2S). Sulfate reduction can occur in both an energy consuming assimilatory pathway and an energy producing dissimilatory pathway. The assimilatory pathway, which is found in a wide range of organisms, produces reduced sulfur compounds for the biosynthesis of S-containing amino acids and does not lead to direct excretion of sulfide. In the dissimilatory pathway, which is restricted to obligatory anaerobic bacterial and archaeal lineages, sulfate (or sulfur) is the terminal electron acceptor of the respiratory chain producing large quantities of inorganic sulfide. Both pathways start from the activation of sulfate by reaction with ATP to form adenylyl sulfate (APS). In the assimilatory pathway [MD:M00176] APS is converted to 3'-phosphoadenylyl sulfate (PAPS) and then reduced to sulfite, and sulfite is further reduced to sulfide by the assimilatory sulfite reductase. In the dissimilatory pathway [MD:M00596] APS is directly reduced to sulfite, and sulfite is further reduced to sulfide by the dissimilatory sulfite reductase. The capacity for oxidation of sulfur is quite widespread among bacteria and archaea, comprising phototrophs and chemolithoautotrophs. The SOX (sulfur-oxidation) system [MD:M00595] is a well-known sulfur oxidation pathway and is found in both photosynthetic and non-photosynthetic sulfur-oxidizing bacteria. Green sulfur bacteria and purple sulfur bacteria carry out anoxygenic photosynthesis with reduced sulfur compounds such as sulfide and elemental sulfur, as well as thiosulfate (in some species with the SOX system), as the electron donor for photoautotrophic growth. In some chemolithoautotrophic sulfur oxidizers (such as Thiobacillus denitrificans), it has been suggested that dissimilatory sulfur reduction enzymes operate in the reverse direction, forming a sulfur oxidation pathway from sulfite to APS and then to sulfate.
Class
Metabolism; Energy metabolism
Pathway map
map00920  Sulfur metabolism
map00920

Module
M00021  Cysteine biosynthesis, serine => cysteine [PATH:map00920]
M00176  Assimilatory sulfate reduction, sulfate => H2S [PATH:map00920]
M00595  Thiosulfate oxidation by SOX complex, thiosulfate => sulfate [PATH:map00920]
M00596  Dissimilatory sulfate reduction, sulfate => H2S [PATH:map00920]
Other DBs
GO: 0006790
Reference
  Authors
Grein F, Ramos AR, Venceslau SS, Pereira IA
  Title
Unifying concepts in anaerobic respiration: Insights from dissimilatory sulfur metabolism.
  Journal
Biochim Biophys Acta 1827:145-60 (2013)
DOI:10.1016/j.bbabio.2012.09.001
Reference
  Authors
Fauque GD, Barton LL
  Title
Hemoproteins in dissimilatory sulfate- and sulfur-reducing prokaryotes.
  Journal
Adv Microb Physiol 60:1-90 (2012)
DOI:10.1016/B978-0-12-398264-3.00001-2
Reference
  Authors
Sakurai H, Ogawa T, Shiga M, Inoue K
  Title
Inorganic sulfur oxidizing system in green sulfur bacteria.
  Journal
Photosynth Res 104:163-76 (2010)
DOI:10.1007/s11120-010-9531-2
Reference
  Authors
Falkenby LG, Szymanska M, Holkenbrink C, Habicht KS, Andersen JS, Miller M, Frigaard NU
  Title
Quantitative proteomics of Chlorobaculum tepidum: insights into the sulfur metabolism of a phototrophic green sulfur bacterium.
  Journal
FEMS Microbiol Lett 323:142-50 (2011)
DOI:10.1111/j.1574-6968.2011.02370.x
Reference
  Authors
Gregersen LH, Bryant DA, Frigaard NU
  Title
Mechanisms and evolution of oxidative sulfur metabolism in green sulfur bacteria.
  Journal
Front Microbiol 2:116 (2011)
DOI:10.3389/fmicb.2011.00116
Reference
  Authors
Beller HR, Chain PS, Letain TE, Chakicherla A, Larimer FW, Richardson PM, Coleman MA, Wood AP, Kelly DP.
  Title
The genome sequence of the obligately chemolithoautotrophic, facultatively anaerobic bacterium Thiobacillus denitrificans.
  Journal
J Bacteriol 188:1473-88 (2006)
DOI:10.1128/JB.188.4.1473-1488.2006
Reference
PMID:9695921
  Authors
Pott AS, Dahl C
  Title
Sirohaem sulfite reductase and other proteins encoded by genes at the dsr locus of Chromatium vinosum are involved in the oxidation of intracellular sulfur.
  Journal
Microbiology 144 ( Pt 7):1881-94 (1998)
DOI:10.1099/00221287-144-7-1881
Reference
  Authors
Frigaard NU, Dahl C
  Title
Sulfur metabolism in phototrophic sulfur bacteria.
  Journal
Adv Microb Physiol 54:103-200 (2009)
DOI:10.1016/S0065-2911(08)00002-7
Related
pathway
map00260  Glycine, serine and threonine metabolism
map00270  Cysteine and methionine metabolism
map00680  Methane metabolism
map00720  Other carbon fixation pathways
KO pathway
ko00920   
LinkDB

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