|Gene:||hybC||Accession Numbers: EG11801 (MetaCyc), b2994, ECK2988|
Species: Escherichia coli K-12 substr. MG1655
Component of: hydrogenase 2 (summary available)
HybC is the large subunit of hydrogenase 2. Hydrogenase 2 is associated with the periplasmic side of the cytoplasmic membrane [Ballantine86, Rodrigue96]. HybC is processed; N-terminal sequencing of the mature protein confirmed that processing does not occur at the N terminus [Sargent98], while alteration of the C terminus of HybC interferes with processing [Zhang03d].
HybC and HybO are coordinately assembled and processed; the presence of both subunits, nickel acquisition and the subsequent processing of HybC, and the N-terminal signal sequence of HybO are required for export of both subunits by the Tat system [Rodrigue96, Rodrigue99].
Expression of the hyb operon is induced under anaerobic conditions and repressed by nitrate [Richard99].
Locations: periplasmic space, inner membrane
|Map Position: [3,139,308 <- 3,141,011]|
Molecular Weight of Polypeptide: 62.491 kD (from nucleotide sequence)
Unification Links: ASAP:ABE-0009828 , CGSC:33418 , DIP:DIP-36022N , EchoBASE:EB1749 , EcoGene:EG11801 , EcoliWiki:b2994 , Mint:MINT-1254866 , OU-Microarray:b2994 , PortEco:hybC , PR:PRO_000022949 , Pride:P0ACE0 , Protein Model Portal:P0ACE0 , RefSeq:NP_417468 , RegulonDB:EG11801 , SMR:P0ACE0 , String:511145.b2994 , UniProt:P0ACE0
|Biological Process:||GO:0009061 - anaerobic respiration
GO:0055114 - oxidation-reduction process [UniProtGOA11, GOA01]
|Molecular Function:||GO:0008901 - ferredoxin hydrogenase activity
GO:0009055 - electron carrier activity
GO:0016151 - nickel cation binding [GOA01]
GO:0016491 - oxidoreductase activity [UniProtGOA11]
GO:0033748 - hydrogenase (acceptor) activity [GOA01a]
GO:0046872 - metal ion binding [UniProtGOA11]
|Cellular Component:||GO:0005886 - plasma membrane
GO:0016020 - membrane [UniProtGOA11]
GO:0030288 - outer membrane-bounded periplasmic space
|MultiFun Terms:||metabolism → energy metabolism, carbon → anaerobic respiration|
|metabolism → energy production/transport → electron donors|
Subunit of: hydrogenase 2
Synonyms: HYD2, hydrogenase-2
Species: Escherichia coli K-12 substr. MG1655
Subunit composition of
hydrogenase 2 = [HybA][HybB][HybO][HybC]
hydrogenase 2 4Fe-4S ferredoxin-type component = HybA (summary available)
predicted hydrogenase 2 cytochrome b type component = HybB (summary available)
hydrogenase 2, small subunit = HybO (summary available)
hydrogenase 2, large subunit = HybC (summary available)
There are four hydrogenases in E. coli which are synthesized in response to different physiological conditions. Hydrogenase 2 is a membrane-bound, nickel containing enzyme produced under anaerobic conditions. It is thought that hydrogenase 2 catalyzes the H2-dependent reduction of quinone [Ballantine86, Sawers94, Sargent98].
Trypsin treatment of membranes releases an active, soluble fragment of hydrogenase 2 which consists of the large and small subunits [Ballantine86]. The complete enzyme complex is thought to consist of the HybA, HybB, HybC, and HybO subunits [Dubini02].
The substrate specificity of hydrogenase 2 for various quinones is unknown [Laurinavichene01].
Hydrogenase 2 activity is reduced in a feoB null strain and eliminated in a feoB/entC double null mutant indicating that the principal route of iron uptake for the synthesis of this enzyme is via the ferrous iron and ferric enterobactin systems [Pinske11].
Locations: periplasmic space
|Cellular Component:||GO:0030288 - outer membrane-bounded periplasmic space [Rodrigue99]|
Enzymatic reaction of: hydrogenase
The representation of the hydrogenase 2 complex indiates transfer of protons across the membrane where protons from MQH2 (or QH2) are produced at the periplasmic side of the complex. This representation has not been experimentally established and is therefore speculative.
|Chain||2 -> 552|
|Propeptide||553 -> 567|
10/20/97 Gene b2994 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG11801; confirmed by SwissProt match.
Ballantine86: Ballantine SP, Boxer DH (1986). "Isolation and characterisation of a soluble active fragment of hydrogenase isoenzyme 2 from the membranes of anaerobically grown Escherichia coli." Eur J Biochem 1986;156(2);277-84. PMID: 3516690
Dubini02: Dubini A, Pye RL, Jack RL, Palmer T, Sargent F (2002). "How bacteria get energy from hydrogen: a genetic analysis of periplasmic hydrogen oxidation in Escherichia coli." Int J Hydrogen Energy 27(11-12);1413-1420.
Laurinavichene01: Laurinavichene TV, Tsygankov AA (2001). "H2 consumption by Escherichia coli coupled via hydrogenase 1 or hydrogenase 2 to different terminal electron acceptors." FEMS Microbiol Lett 202(1);121-4. PMID: 11506918
Pinske11: Pinske C, Sawers G (2011). "Iron restriction induces preferential down-regulation of H(2)-consuming over H(2)-evolving reactions during fermentative growth of Escherichia coli." BMC Microbiol 11;196. PMID: 21880124
Richard99: Richard DJ, Sawers G, Sargent F, McWalter L, Boxer DH (1999). "Transcriptional regulation in response to oxygen and nitrate of the operons encoding the [NiFe] hydrogenases 1 and 2 of Escherichia coli." Microbiology 145 ( Pt 10);2903-12. PMID: 10537212
Rodrigue96: Rodrigue A, Boxer DH, Mandrand-Berthelot MA, Wu LF (1996). "Requirement for nickel of the transmembrane translocation of NiFe-hydrogenase 2 in Escherichia coli." FEBS Lett 392(2);81-6. PMID: 8772179
Rodrigue99: Rodrigue A, Chanal A, Beck K, Muller M, Wu LF (1999). "Co-translocation of a periplasmic enzyme complex by a hitchhiker mechanism through the bacterial tat pathway." J Biol Chem 274(19);13223-8. PMID: 10224080
Sargent98: Sargent F, Ballantine SP, Rugman PA, Palmer T, Boxer DH (1998). "Reassignment of the gene encoding the Escherichia coli hydrogenase 2 small subunit--identification of a soluble precursor of the small subunit in a hypB mutant." Eur J Biochem 1998;255(3);746-54. PMID: 9738917
Zhang03d: Zhang M, Pradel N, Mandrand-Berthelot MA, Yu Z, Wu LF (2003). "Effect of alteration of the C-terminal extension on the maturation and folding of the large subunit of the Escherichia coli hydrogenase-2." Biochimie 85(6);575-9. PMID: 12829374
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