Database Retrieval System V1.0

Name hydB
Function
Part of a bifunctional enzyme complex that functions as an NADPH-dependent hydrogen-evolving hydrogenase with sulfur reducing activity. •
Definition sulfhydrogenase subunit beta (sulfur reductase) [EC:1.12.98.4].
AA seq
MPEGHVPTAGEAIIDREGLQALLDALGARGFSVIGPRIRDEAIVYAPLRNVADLPEGWTD RQDGGRYRLERRGDRALFGYAVGPHSWKQFLFPPRQRLWQARRTEAGFDLLEEPPPSERW AFLGIRACELHALAIQDRVFLGGSHPDRSYAERRRDLFLVALQCGEPSGTCFCVSMETGP KASSGFDLALTELLGDGSHRFLVEVGSRAGEEILAAIPHRSAGEADRREAEAVLDSTASR MGRTLDTRGIRELLQDHPEHPRWEEVATRCLACANCTMVCPTCFCSTVEDHTALTGESAE RTRLWDSCFSLDFSYLHGGSVRKEIRSRYRQWITHKLSTWFDQFGSSGCVGCGRCITWCP VGIDITEEVRAIRSSLLEPTHA388
Structure
Reference
PMIDTitle & AuthorAbstractYear
07704275Characterization of the locus encoding the [Ni-Fe] sulfhydrogenase from the archaeon Pyrococcus furiosus: evidence for a relationship to bacterial sulfite reductases. Pedroni P, Della Volpe A, Galli G, Mura GM, Pratesi C, Grandi G. The hydBGDA genes, which encode the four subunits beta, gamma, delta and alpha of the [Ni-Fe] hydrogenase from the archaeon Pyrococcus furiosus, have been isolated and sequenced using a PCR/IPCR-based strategy. From the sequence analysis it appears that the four structural genes are tightly linked and organized in a single transcription unit. The hydD and hydA gene products are related to the small and the large subunits of several archaeal and eubacterial [Ni-Fe] hydrogenases with an overall degree of sequence relatedness ranging from 35% to 50% (identity + similarity). In particular, the amino acid sequence motifs involved in the accommodation of nickel and iron-sulfur clusters are conserved. In addition, the database search revealed that the hydB and hydG gene products are homologous to the asrA- and asrB-encoded subunits of the sulfite reductase enzyme from Salmonella typhimurium. This is particularly interesting in view of the recent finding that the P. furiosus hydrogenase appears to be a bifunctional enzyme endowed with both proton- and sulfur-reducing activities. 1995
18389482Hydrogenase of the hyperthermophile Pyrococcus furiosus is an elemental sulfur reductase or sulfhydrogenase: evidence for a sulfur-reducing hydrogenase ancestor. Ma K, Schicho RN, Kelly RM, Adams MW. Microorganisms growing near and above 100 degrees C have recently been discovered near shallow and deep sea hydrothermal vents. Most are obligately dependent upon the reduction of elemental sulfur (S0) to hydrogen sulfide (H2S) for optimal growth, even though S0 reduction readily occurs abiotically at their growth temperatures. The sulfur reductase activity of the anaerobic archaeon Pyrococcus furiosus, which grows optimally at 100 degrees C by a metabolism that produces H2S if S0 is present, was found in the cytoplasm. It was purified anaerobically and was shown to be identical to the hydrogenase that had been previously purified from this organism. Both S0 and polysulfide served as substrates for H2S production, and the S0 reduction activity but not the H2-oxidation activity was enhanced by the redox protein rubredoxin. The H2-oxidizing and S0-reduction activities of the enzyme also showed different responses to pH, temperature, and inhibitors. This bifunctional "sulfhydrogenase" enzyme can, therefore, dispose of the excess reductant generated during fermentation using either protons or polysulfides as the electron acceptor. In addition, purified hydrogenases from both hyperthermophilic and mesophilic representatives of the archaeal and bacterial domains were shown to reduce S0 to H2S. It is suggested that the function of some form of ancestral hydrogenase was S0 reduction rather than, or in addition to, the reduction of protons. 1993

Pedroni P , Volpe A D , Galli G , et al. Characterization of the locus encoding the [Ni-Fe] sulfhydrogenase from the archaeon Pyrococcus furiosus: evidence for a relationship to bacterial sulfite reductases[J]. Microbiology, 1995, 141(2):449-458. Ma K , Schicho R N , Adams K M W W . Hydrogenase of the Hyperthermophile Pyrococcus furiosus is an Elemental Sulfur Reductase or Sulfhydrogenase: Evidence for a Sulfur-Reducing Hydrogenase Ancestor[J]. Proceedings of the National Academy of Sciences of the United States of America, 1993, 90(11):5341-5344.