{PDOC00686}
{PS00880; ACB_1}
{PS51228; ACB_2}
{BEGIN}
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* Acyl-CoA-binding (ACB) domain signature and profile *
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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 [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 residues 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 (see <PDOC50088>) [3].

The ACB  domain consists of four alpha-helices arranged in a bowl shape with a
highly exposed  acyl-CoA-binding  site  (see  <PDB:1HBK>). 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].

ACBP belongs to a family that also includes:

 - Endozepine-like peptide (ELP) (gene DBIL5) from mouse [5]. ELP is a testis-
   specific  ACBP homolog 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.

As a signature pattern we selected  the region  that corresponds to residue 19
to 37  in  mammalian ACBP. We also developed a profile which covers the entire
ACB domain.

-Consensus pattern: [PTLV]-[GSTA]-x-[DENQA]-x-[LMFK]-x(2)-[LIVMFY]-[YV]-[GSA]-
                    x-[FYH]-K-Q-[GSAV]-[STL]-x-G
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Last update: July 2006 / Text revised; profile added.

[ 1] Rose T.M., Schultz E.R., Todaro G.J.
     "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. 89:11287-11291(1992).
     PubMed=1454809
[ 2] Costa E., Guidotti A.
     "Diazepam binding inhibitor (DBI): a peptide with multiple biological
     actions."
     Life Sci. 49:325-344(1991).
     PubMed=1649940
[ 3] Burton M., Rose T.M., Faergeman N.J., Knudsen J.
     "Evolution of the acyl-CoA binding protein (ACBP)."
     Biochem. J. 392:299-307(2005).
     PubMed=16018771; DOI=10.1042/BJ20050664
[ 4] van Aalten D.M.F., Milne K.G., Zou J.Y., Kleywegt G.J., Bergfors T.,
     Ferguson M.A.J., Knudsen J., Jones T.A.
     "Binding site differences revealed by crystal structures of Plasmodium
     falciparum and bovine acyl-CoA binding protein."
     J. Mol. Biol. 309:181-192(2001).
     PubMed=11491287; DOI=10.1006/jmbi.2001.4749
[ 5] Pusch W., Balvers M., Hunt N., Ivell R.
     "A novel endozepine-like peptide (ELP) is exclusively expressed in
     male germ cells."
     Mol. Cell. Endocrinol. 122:69-80(1996).
     PubMed=8898349
[ 6] Suk K., Kim Y.-H., Hwang D.-Y., Ihm S.H., Yoo H.J., Lee M.S.
     "Molecular cloning and expression of a novel human cDNA related to the
     diazepam binding inhibitor."
     Biochim. Biophys. Acta 1454:126-131(1999).
     PubMed=10354522

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{END}