Sulfide: Biosynthesis from Sulfate


The uptake and reduction of inorganic sulfate and its subsequent assimilation into organic biomolecules is an elaborate and energy‐consuming process. This pathway, involving many enzymes, is tightly regulated to control the production of reactive intermediates and to ensure that the flux through the pathway matches the cell's requirements for reduced sulfur.

Keywords: cysteine biosynthesis; cysteine regulon; sulfur metabolism; sulfate reduction; organic sulfur sources

Figure 1.

The pathway of cysteine biosynthesis. (a) The sulfate uptake and reduction arm of the pathway are shown on the left with the serine activation step in the middle and thiosulfate uptake on the right. (b) The sulfate‐to‐sulfide reduction branch of the pathway with the molecular structures of the sulfur containing intermediates drawn in ChemDraw accompanied by structures of the enzymes/transporter proteins (pdb codes 1sbp (sulfate binding protein), 1l7v (membrane components of the vitamin B12 uptake system, which are representative of an ABC transporter), 1g8f (ATP sulfurylase), 1m7 h (APS kinase), 1sur (PAPS reductase), 5aop (sulfite reductase in which the atoms of the Fe4S4 cluster are represented as green spheres and the sirohaem moiety is shown in ball‐and‐stick)) drawn using MOLSCRIPT.

Figure 2.

Regulation of cysteine biosynthesis in E. coli. (a) Scheme illustrating the components involved with the species that bind to CysB boxed. Feedback inhibition of serine acetyltransferase by cysteine blocks the accumulation of the inducer N‐acetylserine (blue) that is required for CysB‐mediated activation of the genes for sulfate reduction. Thiosulfate and sulfide (red) compete with N‐acetylserine for binding to CysB and act as antiinducers. (b) CysB binding sites at various cys promoters. In all, 19 base‐pair binding sites for CysB subunits are represented by boxes, their relative orientation indicated by arrows. The locations of these sites relative to the transcription start site are indicated below. (c) Ribbon drawing of the crystal structure of a dimeric cofactor‐binding fragment of CysB (pdb code 1al3) with bound sulfate ions in ball‐and‐stick representation.



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Further Reading

Holland IB, Cole SPC, Kuchler K and Higgins CF (2003) ABC Proteins: from Bacteria to Man. London: Elsevier Science Ltd. Academic Press.

Crane BR and Getzoff ED (1996) The relationship between structure and function for the sulfite reductases. Current Opinion in Structural Biology 6: 744–756.

Kertesz MA (2000) Riding the sulfur cycle – metabolism of sulfonates and sulfate esters in Gram‐negative bacteria. FEMS Microbiology Reviews 24: 135–175.

Kredich NM (1996) Biosynthesis of cysteine. In: Neidhardt FC and Umbarger HE (eds) Escherichia coli and Salmonella typhimurium: Cellular and Molecular Biology. Washington, DC: American Society for Microbiology.

Leustek T (2002) Sulfate metabolism. In: Somerville CR and Meyerowitz EM (eds) The Arabidopsis Book. Rockville, MD: American Society of Plant Biologists, doi/10.1199/tab.0017,

Leustek T, Martin MN, Bick JA and Davies JP (2000) Pathways and regulation of sulfur metabolism revealed through molecular and genetic studies. Annual Review of Plant Physiology and Plant Molecular Biology 51: 141–165.

Marzluf GA (1997) Molecular genetics of sulfur assimilation in filamentous fungi and yeast. Annual Review of Microbiology 51: 73–96.

Thomas D and SurdinKerjan Y (1997) Metabolism of sulfur amino acids in Saccharomyces cerevisiae. Microbiology and Molecular Biology Reviews 61: 503–532.

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How to Cite close
Verschueren, Koen HG, and Wilkinson, Anthony J(Sep 2005) Sulfide: Biosynthesis from Sulfate. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1038/npg.els.0001405]