|Gene:||hybO||Accession Numbers: G7554 (MetaCyc), b2997, ECK2991|
Synonyms: yghV, hyb0, hydrogenase 2 β subunit
Species: Escherichia coli K-12 substr. MG1655
Component of: hydrogenase 2 (extended summary available)
HybO is the small subunit of hydrogenase 2; sequence analysis suggests it contains three Fe-S clusters; expected to be two [4Fe-4S] and one [3Fe-4S] as has been shown by x-ray crystallography for the small subunit of a Desulfovibrio gigas [Ni-Fe] hydrogenase [Sargent98, Volbeda95]. HybO contains a twin-arginine signal sequence which is required for membrane targeting by the Tat system. HybO accumulates in a soluble precursor form in a hypB mutant which is unable to insert nickel into the large subunit (HybC) of hydrogenase 2 [Sargent98].
HybO and HybC are coordinately assembled and processed; the presence of both subunits, acquisition of the [Ni-Fe] cofactor and subsequent processing of HybC are required for export of the complex by the Tat system [Rodrigue96, Rodrigue99].
Locations: inner membrane, periplasmic space
|Map Position: [3,143,165 <- 3,144,283]|
Molecular Weight of Polypeptide: 39.652 kD (from nucleotide sequence)
Unification Links: ASAP:ABE-0009834 , DIP:DIP-36024N , EchoBASE:EB2828 , EcoGene:EG13006 , EcoliWiki:b2997 , Mint:MINT-8046452 , ModBase:P69741 , OU-Microarray:b2997 , PortEco:hybO , PR:PRO_000022953 , Protein Model Portal:P69741 , RefSeq:NP_417471 , RegulonDB:G7554 , SMR:P69741 , String:511145.b2997 , Swiss-Model:P69741 , UniProt:P69741
Relationship Links: InterPro:IN-FAMILY:IPR001821 , InterPro:IN-FAMILY:IPR006137 , InterPro:IN-FAMILY:IPR006311 , InterPro:IN-FAMILY:IPR019546 , InterPro:IN-FAMILY:IPR027394 , Panther:IN-FAMILY:PTHR30013 , Pfam:IN-FAMILY:PF01058 , Pfam:IN-FAMILY:PF14720 , Prints:IN-FAMILY:PR00614 , Prosite:IN-FAMILY:PS51318
|Biological Process:||GO:0009061 - anaerobic respiration
GO:0055114 - oxidation-reduction process [UniProtGOA11a, GOA01]
|Molecular Function:||GO:0005515 - protein binding
[Chan10a, Chan09, Butland06, Butland05]
GO:0008901 - ferredoxin hydrogenase activity [GOA01]
GO:0009055 - electron carrier activity
GO:0016491 - oxidoreductase activity [UniProtGOA11a]
GO:0033748 - hydrogenase (acceptor) activity [GOA01a]
GO:0046872 - metal ion binding [UniProtGOA11a]
GO:0051536 - iron-sulfur cluster binding [UniProtGOA11a, GOA01, Sargent98]
GO:0051538 - 3 iron, 4 sulfur cluster binding [UniProtGOA11a]
GO:0051539 - 4 iron, 4 sulfur cluster binding [UniProtGOA11a]
|Cellular Component:||GO:0016020 - membrane
GO:0031236 - extrinsic component of periplasmic side of plasma membrane [Sargent98, Rodrigue99]
GO:0044569 - [Ni-Fe] hydrogenase complex [Dubini02]
GO:0005886 - plasma membrane [UniProtGOA11, UniProtGOA11a, Rodrigue96]
GO:0009375 - ferredoxin hydrogenase complex [GOA01]
GO:0042597 - periplasmic space [UniProtGOA11, UniProtGOA11a]
|MultiFun Terms:||metabolism → energy metabolism, carbon → anaerobic respiration|
|metabolism → energy production/transport → electron donors|
Subunit of: hydrogenase 2
Synonyms: HYD2, hydrogenase-2, hydrogen:menaquinone oxidoreductase 2
Species: Escherichia coli K-12 substr. MG1655
Subunit composition of
hydrogenase 2 = [HybA][HybB][HybO][HybC]
hydrogenase 2 - [Fe-S] binding, ferredoxin-type component HybA = HybA (summary available)
hydrogenase 2 - integral membrane subunit HybB = HybB (summary available)
hydrogenase 2, small subunit = HybO (summary available)
hydrogenase 2, large subunit = HybC (summary available)
Hydrogenase 2 is a membrane-bound, [Ni-Fe] enzyme produced under anaerobic conditions. Hydrogenase 2 is a respiratory enzyme which couples hydrogen oxidation in the periplasm to reduction of the inner membrane quinone pool [Ballantine86, Sargent98]. Hydrogenase 2 participates in H(2) dependent reduction of fumarate, dimethyl sulfoxide and trimethylamine N-oxide [Sawers85, Laurinavichene01, Pinske15] (and see [Unden97].
Hydrogenase 2 is an oxygen sensitive enzyme - it is unable to catalyse H(2) oxidation under aerobic conditions [Laurinavichene01, Lukey10]. Hydrogenase 2 functions optimally at redox potentials lower than -100 to -150 mV [Laurinavichene02, Lukey10]. Hydrogenase 2 is capable of bidirectional catalysis in vitro [Lukey10] and in vivo [Pinske15]. Hydrogenase 2 can function as an H(2) evolving enzyme (ie. as a proton reductant) during fermentative growth with glycerol; this endergonic reaction is driven by the membrane proton gradient and probably functions to prevent over reduction of the quinone pool [Pinske15].
Hydrogenase 2 uses menaquinone/demethylmenaquinone to couple hydrogen oxidation to fumarate reduction during anaerobic respiratory growth with glycerol and fumarate and also during H(2) evolution during fermentation with glycerol; hydrogenase 2 can rapidly switch between H(2) evolution and H(2) oxidation modes in vivo [Pinske15].
Trypsin treatment of membranes releases an active, soluble fragment of hydrogenase 2 which consists of the large and small subunits [Ballantine86]. Hydrogenase 2 is encoded within the hyb operon (hybGFEDCBAO); the complete enzyme complex is thought to consist of the HybA, HybB, HybC and HybO subunits [Menon94, Dubini02]. HybOC forms the core catalytic dimer anchored to the membrane via a hydrophobic helix at the C-terminus of HybO; HybA (a ferredoxin type protein) and HybB (an integral membrane protein) are essential for shuttling electrons to the quinone pool [Dubini02, Pinske15].
HybC and HybO are coordinately assembled and processed; acquisition of the [NiFe] cofactor, C-terminal processing of HybC and subsequent association with the small subunit (HybO) are required prior to export by the Tat system [Rodrigue96, Sargent98, Rodrigue99, Zhang03g, Dubini03]. Maturation and membrane targeting of hydrogenase 2 involves proteins encoded within the hyp and hyb operons (HypB, HypD, HypE, HybD, HybE and HybG) and the HypF protein (reviews: [Bock06, Forzi07]).
Expression of the hyb operon is induced under anaerobic conditions and repressed by nitrate [Richard99].
E. coli K-12 contains a second membrane associated hydrogenase - hydrogenase 1 - and a third hydrogenase - hydrogenase 3 - which is part of the formate hydrogenlyase complex. A potential fourth hydrogenase - hydrogenase 4 - is encoded within the hyf operon.
Locations: periplasmic space, inner membrane
|Biological Process:||GO:0009061 - anaerobic respiration
[Pinske15, Menon94, Sawers85]
GO:0019588 - anaerobic glycerol catabolic process [Pinske15]
GO:0019645 - anaerobic electron transport chain [Laurinavichene01, Pinske15]
GO:1902421 - hydrogen metabolic process [Sawers85]
|Molecular Function:||GO:0005506 - iron ion binding
GO:0009055 - electron carrier activity [Laurinavichene01]
GO:0016151 - nickel cation binding [Ballantine86]
GO:0033748 - hydrogenase (acceptor) activity [Laurinavichene02, Sargent98, Ballantine86]
GO:0047067 - hydrogen:quinone oxidoreductase activity [Pinske15]
|Cellular Component:||GO:0031236 - extrinsic component of periplasmic side of plasma membrane
GO:0044569 - [Ni-Fe] hydrogenase complex [Dubini02, Menon94, Ballantine86]
Enzymatic reaction of: hydrogen:menaquinone oxidoreductase (hydrogenase 2)
The representation of the hydrogenase 2 complex depicts the location of the donor (ie. H2) oxidation site and menaquinone reduction site at opposite sides of the membrane (H+/e- = 1). This representation has not been experimentally established.
|Signal-Sequence||1 -> 37|
|Chain||38 -> 372|
Markus Krummenacker on Tue Oct 14, 1997:
Gene object created from Blattner lab Genbank (v. M52) entry.
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
Butland05: Butland G, Peregrin-Alvarez JM, Li J, Yang W, Yang X, Canadien V, Starostine A, Richards D, Beattie B, Krogan N, Davey M, Parkinson J, Greenblatt J, Emili A (2005). "Interaction network containing conserved and essential protein complexes in Escherichia coli." Nature 433(7025);531-7. PMID: 15690043
Butland06: Butland G, Zhang JW, Yang W, Sheung A, Wong P, Greenblatt JF, Emili A, Zamble DB (2006). "Interactions of the Escherichia coli hydrogenase biosynthetic proteins: HybG complex formation." FEBS Lett 580(2);677-81. PMID: 16412426
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.
Lasserre06: Lasserre JP, Beyne E, Pyndiah S, Lapaillerie D, Claverol S, Bonneu M (2006). "A complexomic study of Escherichia coli using two-dimensional blue native/SDS polyacrylamide gel electrophoresis." Electrophoresis 27(16);3306-21. PMID: 16858726
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
Laurinavichene02: Laurinavichene TV, Zorin NA, Tsygankov AA (2002). "Effect of redox potential on activity of hydrogenase 1 and hydrogenase 2 in Escherichia coli." Arch Microbiol 178(6);437-42. PMID: 12420163
Lukey10: Lukey MJ, Parkin A, Roessler MM, Murphy BJ, Harmer J, Palmer T, Sargent F, Armstrong FA (2010). "How Escherichia coli is equipped to oxidize hydrogen under different redox conditions." J Biol Chem 285(6);3928-38. PMID: 19917611
Menon94: Menon NK, Chatelus CY, Dervartanian M, Wendt JC, Shanmugam KT, Peck HD, Przybyla AE (1994). "Cloning, sequencing, and mutational analysis of the hyb operon encoding Escherichia coli hydrogenase 2." J Bacteriol 176(14);4416-23. PMID: 8021226
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
Pinske15: Pinske C, Jaroschinsky M, Linek S, Kelly CL, Sargent F, Sawers RG (2015). "Physiology and Bioenergetics of [NiFe]-Hydrogenase 2-Catalyzed H2-Consuming and H2-Producing Reactions in Escherichia coli." J Bacteriol 197(2);296-306. PMID: 25368299
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
Sawers85: Sawers RG, Ballantine SP, Boxer DH (1985). "Differential expression of hydrogenase isoenzymes in Escherichia coli K-12: evidence for a third isoenzyme." J Bacteriol 164(3);1324-31. PMID: 3905769
Unden97: Unden G, Bongaerts J (1997). "Alternative respiratory pathways of Escherichia coli: energetics and transcriptional regulation in response to electron acceptors." Biochim Biophys Acta 1320(3);217-34. PMID: 9230919
Volbeda95: Volbeda A, Charon MH, Piras C, Hatchikian EC, Frey M, Fontecilla-Camps JC (1995). "Crystal structure of the nickel-iron hydrogenase from Desulfovibrio gigas." Nature 373(6515);580-7. PMID: 7854413
Zhang03g: 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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