The Ton system can functionally replace the TolB protein in the uptake of mutated colicin U.
The uptake of colicin U into sensitive cells is dependent on the Tol system. Like colicin A and the E-type colicins, colicin U contains the consensus pentapeptide DG(T/S)G(S/W) in the N-terminal 36 amino acids, which have been proposed to be involved in the interaction of colicin U with the Tol proteins. The role of the DGTGW motif in colicin U was studied by converting it into the TonB box motif DTMVV of colicin B. Uptake of the mutated colicin U (DTMVV) depended on TonB and ExbB and still remained TolA- and TolQ-dependent, but no longer required TolB. The Ton system could obviously replace the TolB function in the uptake of the mutated colicin U. The colicin U derivative is the first colicin whose uptake depends on the Ton and the Tol systems.
Universität Tübingen, Germany. holger.pilsl@mikrobio.uni-tuebingen.de
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D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003087:Colicins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D033903:Periplasmic Proteins; D010957:Plasmids / Q000235:genetics; D011995:Recombination, Genetic
D001426:Bacterial Proteins; D003087:Colicins; D029968:Escherichia coli Proteins; C052874:ExbB protein, E coli; D008565:Membrane Proteins; D033903:Periplasmic Proteins; C062094:tolB protein, E coli; C057616:tonB protein, Bacteria; C489181:tonB protein, E coli