ABC transporters belong to the ATP-Binding Cassette (ABC) superfamily which
uses the hydrolysis of ATP to energize diverse biological import and export
systems (see <PDOC00185>). ABC transporters are constituted at least of two
conserved regions: a highly conserved ATP binding cassette (ABC) and a less
conserved transmembrane domain (TMD) (see <PDOC00364>). These regions can be
found on the same protein (mostly bacterial exporters and eukaryotes) or on
two different ones (mostly bacterial importers) [1,2,3]. Nevertheless, in a
wide range of ABC exporters, an additional protease domain of about 130 amino
acid residues is found to be fused to the TMD and the NBD. This domain is a
maturation protease for certain peptide bacteriocins, namely those containing
the double glycine leader motif. These include class II bacteriocins of
Gram-positive and Gram-negative bacteria, as well as some of the lantibiotics,
the CSPs (competence stimulating peptide) and peptides pheromones. The
proteolytic domain reside in the N-terminal region of the protein. It is a
thiol peptidase and belongs to the C39 peptidase family [E1].
Thus all bacteriocin precursors containing double-glycine-type leader peptides
are processed and export concomitantly by a proteolytic domain residing in the
N-termini of their dedicated ABC transporter. It appears that this kind of
processing is more efficient [4,5]. It results in cleavage and translocation
of both peptides simultaneously, probably by processing the signal peptide and
exporting the resulting mature lantibiotic. A number of the proteins are
classified as non-peptidase homologues as they either have been found
experimentally to be without peptidase activity, or to lack amino acid
residues that are believed to be essential for the catalytic activity. Even
though these domains have lost their proteolytic properties they still serve
as substrate-recognition domains .
All different types of transporters containing an ABC peptidase domain are
listed below (references are only provided for recently characterized
The profile does not recognize other ABC proteases involved in complex
export, which seem to be serine proteases. These are not fused to the TMD-
NBD, and seem not to be evolutionnary related to this kind of fused
May 2004 / First entry.
PROSITE method (with tools and information) covered by this documentation:
Holland I.B. Cole S.P.C. Kuchler K. Higgins C.F.
(In) ABC proteins from bacteria to man, Academic Press, San Diego, (2003).
Holland I.B. Blight M.A.
J. Mol. Biol. 293:381-399(1999).
Saurin W. Hofnung M. Dassa E.
Getting in or out: early segregation between importers and exporters in the evolution of ATP-binding cassette (ABC) transporters.
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