Conserved Site

Acyl-CoA-binding protein, ACBP, conserved site (IPR022408)

Short name: Acyl-CoA-binding_prot_CS

Description

This entry represents a motif that corresponds to residue 19 to 37 in mammalian ACBP, adn which contains a conserved site.

Acyl-CoA-binding protein (ACBP) is a small (10 Kd) protein that binds medium- and long-chain acyl-CoA esters with very high affinity and may function as an intracellular carrier of acyl-CoA esters [PMID: 1454809]. ACBP is also known as diazepam binding inhibitor (DBI) or endozepine (EP) because of its ability to displace diazepam from the benzodiazepine (BZD) recognition site located on the GABA type A receptor. It is therefore possible that this protein also acts as a neuropeptide to modulate the action of the GABA receptor [PMID: 1649940].

ACBP is a highly conserved protein of about 90 residues that is found in all four eukaryotic kingdoms, Animalia, Plantae, Fungi and Protista, and in some eubacterial species [PMID: 16018771].

Although ACBP occurs as a completely independent protein, intact ACB domains have been identified in a number of large, multifunctional proteins in a variety of eukaryotic species. These include large membrane-associated proteins with N-terminal ACB domains, multifunctional enzymes with both ACB and peroxisomal enoyl-CoA Delta(3), Delta(2)-enoyl-CoA isomerase domains, and proteins with both an ACB domain and ankyrin repeats (IPR002110) [PMID: 16018771].

The ACB domain consists of four alpha-helices arranged in a bowl shape with a highly exposed acyl-CoA-binding site. The ligand is bound through specific interactions with residues on the protein, most notably several conserved positive charges that interact with the phosphate group on the adenosine-3'phosphate moiety, and the acyl chain is sandwiched between the hydrophobic surfaces of CoA and the protein [PMID: 11491287].

Other proteins containing an ACB domain include:

  • Endozepine-like peptide (ELP) (gene DBIL5) from mouse [PMID: 8898349]. ELP is a testis-specific ACBP homologue that may be involved in the energy metabolism of the mature sperm.
  • MA-DBI, a transmembrane protein of unknown function which has been found in mammals. MA-DBI contains a N-terminal ACB domain.
  • DRS-1 [PMID: 10354522], a human protein of unknown function that contains a N-terminal ACB domain and a C-terminal enoyl-CoA isomerase/hydratase domain.

Contributing signatures

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