Member database | PROSITE patterns |
PROSITE patterns type | conserved site |
Short name | SBP_BACTERIAL_1 |
Description
Bacterial high affinity transport systems are involved in active transport of
solutes across the cytoplasmic membrane. The protein components of these
traffic systems include one or two transmembrane protein components, one or
two membrane-associated ATP-binding proteins (ABC transporters; see
{PDOC00185}) and a high affinity periplasmic solute-binding protein. The later
are thought to bind the substrate in the vicinity of the inner membrane, and
to transfer it to a complex of inner membrane proteins for concentration into
the cytoplasm.
In gram-positive bacteria which are surrounded by a single membrane and have
therefore no periplasmic region the equivalent proteins are bound to the
membrane via an N-terminal lipid anchor. These homolog proteins do not play an
integral role in the transport process per se, but probably serve as receptors
to trigger or initiate translocation of the solute through the membrane by
binding to external sites of the integral membrane proteins of the efflux
system.
In addition at least some solute-binding proteins function in the initiation
of sensory transduction pathways.
On the basis of sequence similarities, the vast majority of these solute-
binding proteins can be grouped
[1] into eight families of clusters, which
generally correlate with the nature of the solute bound.
Family 1 currently includes the following proteins:
- Periplasmic maltose/maltodextrin-binding proteins of Enterobacteriaceae
(gene malE) and homologous lipoprotein in Streptococcus pneumoniae (gene
malX).
- Periplasmic multiple oligo-saccharide binding protein of Streptococcus
mutans (gene msmE), which is involved in the uptake of melibiose, raffinose
and isomaltotriose.
- Periplasmic glycerol-3-phosphate-binding protein of Escherichia coli, a
component of the phosphate-limitation inducible uptake system for
sn-glycerol-3-phosphate and glycerophosphoryl diesters.
- Periplasmic iron-binding protein from Serratia marcescens (gene sfuA) and
the homologous proteins (gene fbp) from Haemophilus influenzae and
Neisseria, which are part of the iron-acquisition system.
- Periplasmic thiamine-binding protein (gene tbpA) from Escherichia coli and
Haemophilus influenzae.
The signature pattern for this family is located in the central section of
the mature proteins.
References
1.Structural, functional, and evolutionary relationships among extracellular solute-binding receptors of bacteria. Tam R, Saier MH Jr. Microbiol. Rev. 57, 320-46, (1993). View articlePMID: 8336670