AHS2

Allophanate hydrolase subunit 2

• SMART accession number: SM00797
• Description: This domain represents subunit 2 of allophanate hydrolase (AHS2).
• Interpro abstract (IPR003778):

  Urea carboxylase (UC) catalyses a two-step, ATP- and biotin-dependent carboxylation reaction of urea. It is composed of biotin carboxylase (BC), carboxyltransferase (CT), and biotin carboxyl carrier protein (BCCP) domains. The CT domain of UC consists of four subdomains, named A, B, C and D. This domain covers the A and B subdomains of the CT domain. This domain covers the whole length of KipA (kinase A) from Bacillus subtilis [ (PUBMED:9334321) ]. It can also be found in S. cerevisiae urea amidolyase Dur1,2, which is a multifunctional biotin-dependent enzyme with domains for urea carboxylase and allophanate (urea carboxylate) hydrolase activity [ (PUBMED:20884691) ].

  KipA forms a complex with KipI, which is covered by the C and D subdomains of the CT. The KipI-KipA complex shares protein structure and sequence similarity with the CT domain of urea amidolyase from K. lactis, but residues that are important for CT catalysis are not conserved in KipA and KipI. Therefore, the KipA-KipI complex is unlikely to have CT activity [ (PUBMED:22869039) ].

  The CT domain is homologous to the Thermus thermophilus protein TTHA0988 ( Q5SJM0 ). However, the subdomain order of TTHA0988 is different compared with that of CT, suggesting distinct fusion events in the evolution of these proteins [ (PUBMED:22277658) ].

There are 16279 AHS2 domains in 16279 proteins in SMART's nrdb database.

Cellular role (predicted cellular role)

Cellular role: metabolism

Metabolism (metabolic pathways involving proteins which contain this domain)

% proteins involved	KEGG pathway ID	Description
56.99	map00220	Urea cycle and metabolism of amino groups
40.86	map00791	Atrazine degradation
1.08	map00640	Propanoate metabolism
1.08	map00280	Valine, leucine and isoleucine degradation

This information is based on mapping of SMART genomic protein database to KEGG orthologous groups. Percentage points are related to the number of proteins with AHS2 domain which could be assigned to a KEGG orthologous group, and not all proteins containing AHS2 domain. Please note that proteins can be included in multiple pathways, ie. the numbers above will not always add up to 100%.

Structure (3D structures containing this domain)

3D Structures of AHS2 domains in PDB

PDB code	Title
3mml	Allophanate Hydrolase Complex from Mycobacterium smegmatis, Msmeg0435-Msmeg0436
3oep	Crystal structure of TTHA0988 in space group P43212
3opf	Crystal structure of TTHA0988 in space group P212121
3ore	Crystal structure of TTHA0988 in space group P6522
3va7	Crystal structure of the Kluyveromyces lactis Urea Carboxylase
5dud	5DUD

Links (links to other resources describing this domain)

• PFAM: AHS2
• INTERPRO: IPR003778