Carbon disulfide hydrolase

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Identifiers
Symbol?
SCOP21can / SCOPe / SUPFAM

Carbon disulfide hydrolase is an enzyme that catalyzes carbon disulfide hydrolysis. It is hexadecameric, weighing 23,576 Da (per molecule).[1]

Carbon disulfide occurs naturally in the mudpots of volcanic solfataras. It is a precursor to hydrogen sulfide, which is an electron donor. The hyperthermophilic Acidianus strain was found to convert CS2 into H2S and CO2.[1]

The enzyme is similar to that of carbonic anhydrases. The enzyme monomer of CS2 hydrolase displays a typical β-carbonic anhydrase fold and active site. Two of these monomers form a closely intertwined dimer with a central β-sheet capped by an α-helical domain. Four dimers form a square octameric ring through interactions of the long arms at the N and C termini. Similar ring structures have been seen in strains of carbonic anhydrases, however, in CS2 hydrolase is an enzyme consisting of two octameric rings form a hexadecamer by interlocking at right angles to each other. This results in the blocking of the entrance to the active site and the formation of a single 15-Å-long, highly hydrophobic tunnel that functions as a specificity filter. This provides a key difference between carbonic anhydrase and CS2 hydrolase. This tunnel determines the enzyme's substrate specificity for CS2, which is hydrophobic as well.

References

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