Homologous Superfamily

Arginine repressor, C-terminal domain superfamily (IPR036251)

Short name: Arg_repress_C_sf

Overlapping entries


The arginine dihydrolase (AD) pathway is found in many prokaryotes and some primitive eukaryotes, an example of the latter being Giardia lamblia (Giardia intestinalis) [PMID: 9504342]. The three-enzyme anaerobic pathway breaks down L-arginine to form 1 mol of ATP, carbon dioxide and ammonia. In simpler bacteria, the first enzyme, arginine deiminase, can account for up to 10% of total cell protein [PMID: 9504342].

Most prokaryotic arginine deiminase pathways are under the control of a repressor gene, termed ArgR [PMID: 1583685]. This is a negative regulator, and will only release the arginine deiminase operon for expression in the presence of arginine [PMID: 9851988]. The crystal structure of apo-ArgR from Bacillus stearothermophilus has been determined to 2.5A by means of X-ray crystallography [PMID: 10331868]. The protein exists as a hexamer of identical subunits, and is shown to have six DNA-binding domains, clustered around a central oligomeric core when bound to arginine. It predominantly interacts with A.T residues in ARG boxes. This hexameric protein binds DNA at its N terminus to repress arginine biosyntheis or activate arginine catabolism. Some species have several ArgR paralogs. In a neighbour-joining tree, some of these paralogous sequences show long branches and differ significantly from the well-conserved C-terminal region.

The C-terminal domain of the arginine repressor is responsible for aginine binding and multimerisation [PMID: 11856827, PMID: 9334747].

GO terms

Biological Process

GO:0051259 protein complex oligomerization

Molecular Function

GO:0034618 arginine binding

Cellular Component

No terms assigned in this category.

Contributing signatures

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