P18190 (MBHS_AZOCH) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Uptake hydrogenase small subunit
EC=1.12.99.6

Alternative name(s):
Hydrogenlyase
Membrane-bound hydrogenase small subunit

Gene names

Name:	hupA
Synonyms:	hupS

Organism

Azotobacter chroococcum mcd 1

Taxonomic identifier

355 [NCBI]

Taxonomic lineage

Bacteria › Proteobacteria › Gammaproteobacteria › Pseudomonadales › Pseudomonadaceae › Azotobacter

Protein attributes

Sequence length	354 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Inferred from homology

General annotation (Comments)

Function	This enzyme recycles the H2 produced by nitrogenase to increase the production of ATP and to protect nitrogenase against inhibition or damage by O2 under carbon- or phosphate-limited conditions.
Catalytic activity	H2 + A = AH2.
Cofactor	Binds 1 3Fe-4S cluster By similarity. Binds 2 4Fe-4S clusters By similarity.
Subunit structure	Heterodimer of a large and a small subunit.
Subcellular location	Cell membrane; Peripheral membrane protein.
Post-translational modification	Predicted to be exported by the Tat system. The position of the signal peptide cleavage has not been experimentally proven.
Sequence similarities	Belongs to the [NiFe]/[NiFeSe] hydrogenase small subunit family.
Caution	An expected iron-sulfur cluster ligand Cys residue was not found at position 231 in this sequence. While a Ser residue may serve as an iron-sulfur cluster ligand, it would be expected to seriously alter the redox behavior of this protein.
Sequence caution	The sequence CAA37133.1 differs from that shown. Reason: Frameshift at position 7.

Ontologies

Keywords
Cellular component	Cell membrane Membrane
Domain	Signal
Ligand	3Fe-4S 4Fe-4S Iron Iron-sulfur Metal-binding
Molecular function	Oxidoreductase
Gene Ontology (GO)
Cellular component	ferredoxin hydrogenase complex Inferred from electronic annotation. Source: InterPro plasma membrane Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular function	3 iron, 4 sulfur cluster binding Inferred from electronic annotation. Source: UniProtKB-KW 4 iron, 4 sulfur cluster binding Inferred from electronic annotation. Source: UniProtKB-KW NADH dehydrogenase (ubiquinone) activity Inferred from electronic annotation. Source: InterPro ferredoxin hydrogenase activity Inferred from electronic annotation. Source: InterPro hydrogenase (acceptor) activity Inferred from electronic annotation. Source: EC metal ion binding Inferred from electronic annotation. Source: UniProtKB-KW quinone binding Inferred from electronic annotation. Source: InterPro
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Signal peptide	1 – 44	44	Tat-type signal Potential
	Chain	45 – 354	310	Uptake hydrogenase small subunit		PRO_0000013423
Sites
	Metal binding	61	1	Iron-sulfur 1 (4Fe-4S) By similarity
	Metal binding	64	1	Iron-sulfur 1 (4Fe-4S) By similarity
	Metal binding	156	1	Iron-sulfur 1 (4Fe-4S) By similarity
	Metal binding	190	1	Iron-sulfur 1 (4Fe-4S) By similarity
	Metal binding	228	1	Iron-sulfur 2 (4Fe-4S); via pros nitrogen By similarity
	Metal binding	231	1	Iron-sulfur 2 (4Fe-4S) By similarity
	Metal binding	256	1	Iron-sulfur 2 (4Fe-4S) By similarity
	Metal binding	262	1	Iron-sulfur 2 (4Fe-4S) By similarity
	Metal binding	271	1	Iron-sulfur 3 (3Fe-4S) By similarity
	Metal binding	290	1	Iron-sulfur 3 (3Fe-4S) By similarity
	Metal binding	293	1	Iron-sulfur 3 (3Fe-4S) By similarity

Sequences

	Sequence		Length	Mass (Da)
	P18190 [UniParc]. Last modified November 15, 2002. Version 3. Checksum: FB7B2AC69B821533	FASTA	354	39,132
	10 20 30 40 50 60 MSQLETXYDV MRRQGITRRS FLKYCSLTGR PCLGPTFAPQ IAHAMETRPP TPVVWLHGLE 70 80 90 100 110 120 CTCCSESFIR SGDPLVKDVV LSMISLDYDD TLMPPRHQGT VEETMRKYKG EYILAVEGNP 130 140 150 160 170 180 PLNEDGMFCI VGGKPFLDQL KHAAKDAKAV IAWGSCASWG CVQAAKPNPT QAVPIHKVIT 190 200 210 220 230 240 DKPMIKVPGC PPIAEVMTGV ITYMLTFGKL PELDRQGRPK MFYGQRIHDK SYRRPHFDAG 250 260 270 280 290 300 QFVEHWDDEG ARKGYCLYKV GCKGPTSYNA CSTVRWNEGT SFPIQAGHGC IGCSEDGFWD 310 320 330 340 350 KGSFYERLTT IPQFGIEKNA DQIGPRGRRG SGAAIAAHAA VTAIKRLQNK GDQA

References

[1]	"The identification, characterization, sequencing and mutagenesis of the genes (hupSL) encoding the small and large subunits of the H2-uptake hydrogenase of Azotobacter chroococcum." Ford C.M., Garg N., Garg R.P., Tibelius K.H., Yates M.G., Arp D.J., Seefeldt L.C. Mol. Microbiol. 4:999-1008(1990) [PubMed: 2215219] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[2]	Yates M.G. Submitted (SEP-1990) to the EMBL/GenBank/DDBJ databases Cited for: SEQUENCE REVISION TO 184.

Cross-references

Sequence databases
EMBL GenBank DDBJ	X52961 Genomic DNA. Translation: CAA37133.1. Frameshift.
3D structure databases
ProteinModelPortal	P18190.
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Family and domain databases
InterPro	IPR006137. NADH_UbQ_OxRdtase-like_20kDa. IPR001821. NiFe_hydrogenase_ssu. IPR006311. TAT_signal. [Graphical view]
Gene3D	G3DSA:3.40.50.700. G3DSA:3.40.50.700. 1 hit.
Pfam	PF01058. Oxidored_q6. 1 hit. [Graphical view]
PIRSF	PIRSF000310. NiFe_hyd_ssu. 1 hit.
PRINTS	PR00614. NIHGNASESMLL.
TIGRFAMs	TIGR00391. HydA. 1 hit.
PROSITE	PS51318. TAT. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

MBHS_AZOCH

Accession

Primary (citable) accession number: P18190

Entry history

Integrated into UniProtKB/Swiss-Prot:	November 1, 1990
Last sequence update:	November 15, 2002
Last modified:	September 21, 2011
This is version 84 of the entry and version 3 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Prokaryotic Protein Annotation Program