unusual ABC-like sugar transporter

Frederik Börnke ricky_boernke at gmx.net
Fri Mar 24 03:15:30 EST 2000

Dear all,

I have cloned this novel gene cluster from Erwinia spec. which is
involved in the metabolism of disaccharides. The genes are pretty
homologues to the genes involved in maltose metabolism in various
other microorganisms and have a somehow classical order of trans
cription (see below).

    E      F       G      H        K       Q

E = periplasmic solute binding protein
F = membrane permease
G = membrane permease
H = ?????
K = ATP binding
Q = breakdown

with the exeption of gene H the gene order is absolutely consistent 
with the examples for sugar uptake systems i have found in the 
literature. Since H is located between G and K in my opinion its
most likely to be involved into transport. PSORT tells me it is 
probably located in the inner membrane which is consistent with
the hydrophobicity traces. I has a very weak homology to members
of family 4 of glycosly hydrolases (22%) although it lacks the
signature sequence. Since I am a plant guy I am a little confused
about things and I would appreciate any input. Is this a common
structure I just overlooked? Are there examples in the literature
for ABC-tranportsystems like this one consisting of more than 4




Frederik Boernke
Research Group of  Molecular Plant Physiology
Institute for Plant Genetics and Crop Plant Research (IPK)
Corrensstr. 3
06466 Gatersleben
Tel.  039482 -5 321
Fax. 039482 -5 515

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