Identification of amino acid sequences that can function as translocators of beta-lactamase in Escherichia coli.
A plasmid vector, pYZ1, was constructed which lacks most of the beta-lactamase signal-peptide coding region, but has a unique EcoRI site spanning codons 2 and 3 of the resultant cytoplasmic beta-lactamase derivative. Short quasi-random DNA sequences were cloned into the EcoRI site and Escherichia coli transformants in which some translocation of beta-lactamase across the cytoplasmic membrane was restored were selected by their ability to survive and form colonies on plates containing a low level of ampicillin. About 15-20% of all in-frame inserts restored some beta-lactamase translocation and the salient feature of these sequences was their marked hydrophobicity. These results are discussed in the light of a similar study in which sequences able to function as translocators of invertase in yeast were cloned and analysed (Kaiser et al., 1987).
Zhang
Y
Y
Microbial Genetics Group, School of Biological Sciences, University of Sussex, Falmer, Brighton, UK.
Broome-Smith
J K
JK
D000595:Amino Acid Sequence; D000667:Ampicillin / Q000494:pharmacology; D001693:Biological Transport, Active; D003001:Cloning, Molecular; D004352:Drug Resistance, Microbial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics*
D000667:Ampicillin; D001618:beta-Lactamases