ABSENCE OF FERRIC ENTEROBACTIN RECEPTOR MODIFICATION ACTIVITY IN MUTANTS OF ESCHERICHIA-COLI K-12 LACKING PROTEIN-A

The modification activity for the ferric enterobactin receptor in the Triton X-100 solubilized outer membrane of Escherichia coli K-12 was adsorbed to a column of p-aminobenzamidine-//-sepharose and eluted with free benzamidine. Recombination of the dialyzed eluate with the filtrate from the column reinstituted conversion of the receptor from 81K to 81K*, the latter exhibiting an apparent molecular weight of 74,000 daltons in sodium dodecyl sulfate polyacrylamide gel analysis. The eluate from the p-aminobenzamidine column was shown to contain a component, coincident on gels with both protein and modification activity, which by mutational and other analyses appears to be identical with protein a of the outer membrane. © 1979.