Urease subunit beta - Helicobacter pylori

Names and origin

Protein names

Recommended name:
    Urease subunit beta
    EC=3.5.1.5
Alternative name(s):
    Urea amidohydrolase subunit beta

Gene names

Name:	ureB
Synonyms:	hpuB
Ordered Locus Names:	HP_0072

Organism

Helicobacter pylori (Campylobacter pylori) [Complete proteome] [HAMAP]

Taxonomic identifier

210 [NCBI]

Taxonomic lineage

Bacteria › Proteobacteria › Epsilonproteobacteria › Campylobacterales › Helicobacteraceae › Helicobacter

Hide | Top

Protein attributes

Sequence length	569 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

Hide | Top

General annotation (Comments)

Function	Ammonia produced by ureolysis increases the gastric pH thereby providing an environment permissive for colonization of the stomach.
Catalytic activity	Urea + H(2)O = CO(2) + 2 NH(3).
Cofactor	Binds 2 nickel ions per subunit.
Pathway	Nitrogen metabolism; urea degradation; CO(2) and NH(3) from urea (urease route): step 1/1.
Subunit structure	Heterohexamer of 3 ureA (alpha) and 3 ureB (beta) subunits. Four heterohexamers assemble to form a 16 nm dodecameric complex.
Subcellular location	Cytoplasm. Note= Also associates with the outer membrane upon autolysis of neighboring bacteria.
Induction	By nickel ions.
Post-translational modification	Carbamylation allows a single lysine to coordinate two nickel ions.
Miscellaneous	The novel dodecameric structure of the enzyme may allow it to remain active at the cell surface at acidic gastric pH. Within this dodecameric structure the 12 active sites are clustered within the interior of the proteinaceous shell. This may allow a high local concentration of ammonia within the enzyme which may protect the nickel-chelating groups from protonation. Strains lacking this gene do not express urease.
Sequence similarities	Belongs to the urease family. Contains 1 urease domain.
Caution	The orthologous protein is known as the alpha subunit (ureC) in most other bacteria.
Biophysicochemical properties	Kinetic parameters: K_M=0.48 mM for urea V_max=1.1 mmol/min/mg enzyme pH dependence: Optimum pH is 8.0. Active from pH 4.0 to 10.0. In unbuffered solutions, the dodecameric complex is active at pH3.0.

Hide | Top

Ontologies

Keywords
Biological process	Virulence
Cellular component	Cytoplasm
Ligand	Metal-binding Nickel
Molecular function	Hydrolase
Technical term	3D-structure Complete proteome Direct protein sequencing
Gene Ontology (GO)
Biological process	pathogenesis Inferred from electronic annotation. Source: UniProtKB-KW urea metabolic process Inferred from electronic annotation. Source: HAMAP
Cellular component	cytoplasm Inferred from electronic annotation. Source: HAMAP
Molecular function	nickel ion binding Inferred from electronic annotation. Source: InterPro urease activity Inferred from electronic annotation. Source: HAMAP
Complete GO annotation...