title: The TolC protein of Escherichia coli K12 is synthesised in a precursor form.
abstract: We examined the biosynthesis of the TolC protein of Escherichia coli K12 in a pulse-chase experiment, followed by immunoprecipitation with anti-TolC antibody and SDS-PAGE of the immunoprecipitate. This showed that TolC protein was originally synthesised in a precursor form (Mr 54 500) which could be chased into the mature form (Mr 52 000). DNA sequencing of a portion of the cloned tolC gene showed that the N-terminus of the mature rotein was preceded by a typical signal sequence of 22 residues (Mr 2542). The initiator Met was preceded by a Shine-Dalgarno sequence, with the correct spacing.
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D001483:Base Sequence; D004269:DNA, Bacterial; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D007120:Immunochemistry; D010455:Peptides / Q000378:metabolism; D011498:Protein Precursors / Q000096:biosynthesis*; D021382:Protein Sorting Signals
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D010455:Peptides; D011498:Protein Precursors; D021382:Protein Sorting Signals