Appearance of elongation factor Tu in the outer membrane of sucrose-dependent spectinomycin-resistant mutants of Escherichia coli.
When sucrose-dependent spectinomycin-resistant (Sucd-Spcr) mutants of Escherichia coli were grown in the absence of sucrose, a new protein appeared in the membrane fraction insoluble in Triton X-100. The protein had a hydrophobic nature. However, unlike other outer membrane proteins the new protein was extracted with sodium dodecyl sarcosinate. The new protein was found to be identical with elongation factor Tu (EF-Tu), as judged from the electrophoretic mobility in three different gel systems, coprecipitation with the antiserum against EF-Tu, the profiles of peptide fragments produced with three different proteases and analyses of N-terminal and C-terminal amino acids. This membrane EF-Tu accounted for 5-10% of total cell EF-Tu. When spheroplasts were pretreated with trypsin, EF-Tu in the outer membrane disappeared. Incubation of cytosol EF-Tu with the outer membrane did not result in the binding of EF-Tu to the membrane. These results indicate that the appearance of EF-Tu in the outer membrane is not due to artificial binding during membrane preparation. It is suggested that the ribosomal alteration resulted in dislocation of the cytosol protein into the outer membrane.
D001426:Bacterial Proteins / Q000302:isolation & purification*; D004352:Drug Resistance, Microbial; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism*; D005779:Immunodiffusion; D008565:Membrane Proteins / Q000302:isolation & purification*; D009154:Mutation; D010444:Peptide Elongation Factor Tu; D010445:Peptide Elongation Factors / Q000302:isolation & purification*; D012269:Ribosomal Proteins / Q000302:isolation & purification; D000198:Spectinomycin / Q000494:pharmacology
D001426:Bacterial Proteins; D008565:Membrane Proteins; D010445:Peptide Elongation Factors; D012269:Ribosomal Proteins; D000198:Spectinomycin; D010444:Peptide Elongation Factor Tu