Variant pili produced by mutants of the Flac plasmid.
Transfer-proficient Flac mutants with reduced abilities to plate various F-specific phages were isolated, either by selection after mutagenesis, or as revertants of Flac traA mutants. In many of the mutants pilus-related properties were altered, including physical adsorption of R17 phage, the number of pili per cell and the outgrowth/retraction equilibrium. Complementation studies showed that the mutations were in traA, suggesting that specific alterations in the amino-acid sequence of the pilin subunit protein were responsible for the altered pilus properties. Complementation between the Flac traA mutants and the derepressed plasmid R100-1 restored phage sensitivity in some cases, suggesting that the incorporation of both mutant and R100-1 subunits into the pilus structure may result in conformational changes which increase the capacity of the pilus to interact with phages.
D003090:Coliphages; D004926:Escherichia coli / Q000235:genetics*; D010861:Fimbriae, Bacterial / Q000648:ultrastructure; D005816:Genetic Complementation Test; D014644:Genetic Variation; D009154:Mutation; D010957:Plasmids