Enzymes
UniProtKB help_outline | 2 proteins |
Enzyme class help_outline |
|
GO Molecular Function help_outline |
|
Reaction participants Show >> << Hide
-
Name help_outline
a menaquinone
Identifier
CHEBI:16374
(CAS: 11032-49-8)
help_outline
Charge
0
Formula
(C5H8)nC11H8O2
Search links
Involved in 47 reaction(s)
Find proteins in UniProtKB for this molecule
Form(s) in this reaction:
-
Identifier: RHEA-COMP:9537Polymer name: a menaquinonePolymerization index help_outline nFormula C11H8O2(C5H8)nCharge (0)(0)nMol File for the polymer
-
- Name help_outline H2 Identifier CHEBI:18276 (CAS: 1333-74-0) help_outline Charge 0 Formula H2 InChIKeyhelp_outline UFHFLCQGNIYNRP-UHFFFAOYSA-N SMILEShelp_outline [H][H] 2D coordinates Mol file for the small molecule Search links Involved in 21 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
-
Name help_outline
a menaquinol
Identifier
CHEBI:18151
Charge
0
Formula
C11H10O2(C5H8)n
Search links
Involved in 53 reaction(s)
Find proteins in UniProtKB for this molecule
Form(s) in this reaction:
-
Identifier: RHEA-COMP:9539Polymer name: a menaquinolPolymerization index help_outline nFormula C11H10O2(C5H8)nCharge (0)(0)nMol File for the polymer
-
Cross-references
RHEA:18641 | RHEA:18642 | RHEA:18643 | RHEA:18644 | |
---|---|---|---|---|
Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
UniProtKB help_outline |
|
|||
EC numbers help_outline | ||||
Gene Ontology help_outline | ||||
KEGG help_outline | ||||
MetaCyc help_outline |
Publications
-
Dross F., Geisler V., Lenger R., Theis F., Krafft T., Fahrenholz F., Kojro E., Duchene A., Tripier D., Juvenal K., Kroeger A. , et al.
-
Identification of histidine residues in Wolinella succinogenes hydrogenase that are essential for menaquinone reduction by H2.
Gross R., Simon J., Lancaster C.R., Kroger A.
The cytochrome b subunit (HydC) of Wolinella succinogenes hydrogenase binds two haem B groups. This is concluded from the haem B content of the isolated hydrogenase and is confirmed by the response of its cytochrome b to redox titration. In addition, three of the four haem B ligands were identifie ... >> More
The cytochrome b subunit (HydC) of Wolinella succinogenes hydrogenase binds two haem B groups. This is concluded from the haem B content of the isolated hydrogenase and is confirmed by the response of its cytochrome b to redox titration. In addition, three of the four haem B ligands were identified by characterizing mutants with the corresponding histidine residues replaced by alanine or methionine. Substitution in HydC of His-25, His-67 or His-186, which are, in addition to His-200, predicted to be haem B ligands, caused the loss of quinone reactivity of the hydrogenase, while the activity of benzylviologen reduction was retained. The corresponding mutants did not grow with H2 as electron donor and either fumarate or polysulphide as terminal electron acceptor. The mutants grown with formate and fumarate did not catalyse electron transport from H2 to fumarate or to polysulphide, or quinone reduction by H2, in contrast to the wild-type strain. Cytochrome b was not reduced by H2 in the Triton X-100 extract of the mutant membranes, which contained wild-type amounts of the mutated HydC protein. Substitution in HydC of His-122, His-158 or His-187, which are predicted not to be haem B ligands, yielded mutants with wild-type properties. Substitution in HydA of His-188 or of His-305 resulted in mutants with the same properties as those lacking one of the haem B ligands of HydC. His-305 is located in the membrane-integrated C-terminal helix of HydA. His-188 of HydA is predicted to be a ligand of the distal iron-sulphur centre that may serve as the direct electron donor to the haem B groups of HydC. The results suggest that each of the three predicted haem B ligands of HydC tested (out of four) is required for electron transport from H2 to either fumarate or polysulphide, and for quinone reactivity. This also holds true for the two conserved histidine residues of HydA. << Less
-
The quinone-reactive Ni/Fe-hydrogenase of Wolinella succinogenes.
Dross F., Geisler V., Lenger R., Theis F., Krafft T., Fahrenholz F., Kojro E., Duchene A., Tripier D., Juvenal K., Kroeger A. , et al.
The hydrogenase (Hyd) isolated from the cytoplasmic membrane of Wolinella succinogenes consists of three polypeptides (HydA, HydB and HydC) and contains cytochrome b (6.4 mumol/g protein), which was reduced upon the addition of H2. The enzyme catalyzed the reduction of 2,3-dimethyl-1,4-naphthoquin ... >> More
The hydrogenase (Hyd) isolated from the cytoplasmic membrane of Wolinella succinogenes consists of three polypeptides (HydA, HydB and HydC) and contains cytochrome b (6.4 mumol/g protein), which was reduced upon the addition of H2. The enzyme catalyzed the reduction of 2,3-dimethyl-1,4-naphthoquinone with H2, in contrast to an earlier preparation which was made up of HydA and HydB only and did not contain cytochrome b (Unden, G., Böcher, R., Knecht, J. & Kröger, A. (1982) FEBS Lett. 145, 230-234). This suggests that HydC is a cytochrome b which serves as a mediator in the electron transfer from H2 to the quinone. The hydrogenase genes were cloned, sequenced and identified by sequence comparison with the N-termini of the three subunits. The three genes were arranged in the order hydA, hydB, hydC, with the transcription start site in front of hydA, and were present only once on the genome. Separated by an intergene region of 69 nucleotides, hydC was followed by at least two more open reading frames of unknown function. The amino acid sequences derived from hydA, hydB and hydC were similar to those of the membrane Ni-hydrogenases of seven other bacteria. HydA and HydB also showed similarity to the small and the large subunits of periplasmic Ni-hydrogenases. HydC was predicted to contain four hydrophobic segments which might span the bacterial membrane. Two histidine residues located in hydrophobic segments are conserved in the corresponding sequences of the other membrane hydrogenases and might ligate the haem B. << Less