Acyl-CoA-binding protein explained
| Symbol: | ACBP |
| ACBP |
| Width: | 270 |
| Pfam: | PF00887 |
| Interpro: | IPR000582 |
| Prosite: | PDOC00686 |
| Scop: | 1aca |
| Opm Family: | 295 |
| Opm Protein: | 2wh5 |
| Cdd: | cd00435 |
| Membranome Superfamily: | 497 |
In molecular biology, the acyl-CoA-binding protein (ACBP) is a small (10 kDa) 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.[1] 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.[2]
ACBP is a highly conserved protein of about 90 amino acids that is found in all four eukaryotic kingdoms, Animalia, Plantae, Fungi and Protista, and in some eubacterial species.[3]
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.[3]
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.[4]
Other proteins containing an ACB domain include:
- Endozepine-like peptide (ELP) (gene DBIL5) from mouse.[5] 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,[6] a human protein of unknown function that contains a N-terminal ACB domain and a C-terminal enoyl-CoA isomerase/hydratase domain.
Notes and References
- Rose TM, Schultz ER, Todaro GJ . Molecular cloning of the gene for the yeast homolog (ACB) of diazepam binding inhibitor/endozepine/acyl-CoA-binding protein . Proc. Natl. Acad. Sci. U.S.A. . 89 . 23 . 11287–91 . December 1992 . 1454809 . 50535 . 10.1073/pnas.89.23.11287. free .
- Costa E, Guidotti A . Diazepam binding inhibitor (DBI): a peptide with multiple biological actions . Life Sci. . 49 . 5 . 325–44 . 1991 . 1649940 . 10.1016/0024-3205(91)90440-M. free .
- Burton M, Rose TM, Faergeman NJ, Knudsen J . Evolution of the acyl-CoA binding protein (ACBP) . Biochem. J. . 392 . Pt 2 . 299–307 . December 2005 . 16018771 . 1316265 . 10.1042/BJ20050664 .
- van Aalten DM, Milne KG, Zou JY, Kleywegt GJ, Bergfors T, Ferguson MA, Knudsen J, Jones TA . Binding site differences revealed by crystal structures of Plasmodium falciparum and bovine acyl-CoA binding protein . J. Mol. Biol. . 309 . 1 . 181–92 . May 2001 . 11491287 . 10.1006/jmbi.2001.4749 .
- Pusch W, Balvers M, Hunt N, Ivell R . A novel endozepine-like peptide (ELP) is exclusively expressed in male germ cells . Mol. Cell. Endocrinol. . 122 . 1 . 69–80 . August 1996 . 8898349 . 10.1016/0303-7207(96)03874-9 . 36504570 .
- Suk K, Kim YH, Hwang DY, Ihm SH, Yoo HJ, Lee MS . Molecular cloning and expression of a novel human cDNA related to the diazepam binding inhibitor . Biochim. Biophys. Acta . 1454 . 1 . 126–31 . May 1999 . 10354522 . 10.1016/s0925-4439(99)00033-2. free .
