Rescue by vitamin B12 of Escherichia coli cells treated with colicins A and E allows measurement of the kinetics of colicin binding on BtuB.
Sensitivity of Escherichia coli bacteria to colicins A and E1 was significantly increased by overproduction of the BtuB receptor protein. The amount of vitamin B12 needed before colicins A and E1 treatment to protect cells against killing was found to be a function of the number of BtuB molecules present at the cell surface. Cells treated by colicins A and E were rescued from killing by addition of vitamin B12 shortly after colicin treatment. The rate of reversal by vitamin B12 may correspond to the kinetics of irreversible binding to BtuB of the various colicins.
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Centre de Biochimie et de Biologie Moléculaire, CNRS, Marseille, France.
D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D003087:Colicins / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects* / Q000378:metabolism; D029968:Escherichia coli Proteins; D007700:Kinetics; D026901:Membrane Transport Proteins; D018000:Receptors, Peptide / Q000378:metabolism*; D014805:Vitamin B 12 / Q000378:metabolism / Q000494:pharmacology*
D001425:Bacterial Outer Membrane Proteins; C044592:BtuB protein, E coli; D003087:Colicins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D018000:Receptors, Peptide; D014805:Vitamin B 12