Carboxyltransferase domain, subdomain C and D (IPR003833)

Short name: CT_C_D

Overlapping homologous superfamilies

Domain relationships



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 C and D subdomains of the CT domain. This domain covers the whole length of kipI (kinase A inhibitor) from Bacillus subtilis [PMID: 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 [PMID: 20884691].

KipI forms a complex with KipA, which is covered by the A and B 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 [PMID: 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 [PMID: 22277658].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.