Quantitative immunoprecipitation of the lactose transporter from Escherichia coli confirms stoichiometry of substrate binding.
A procedure is presented for the immunoprecipitation of the E. coli lactose transporter which may be applicable to other membrane protein antigens. Antibodies to its chemically synthesized C-terminal decapeptide specifically precipitate 6.0 +/- 0.2% of the radioactivity from solubilized [14C]amino-acid-labeled total cell envelopes of the transporter-overproducing strain T206 corresponding to 1.0 +/- 0.1 nmol transporter/mg total membrane protein. Comparison with galactoside binding yields a stoichiometry of 1.1 +/- 0.2 mol galactoside bound/mol transporter.
D011232:Chemical Precipitation; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D005697:Galactosides / Q000378:metabolism*; D006027:Glycosides / Q000378:metabolism*; D007158:Immunologic Techniques; D008565:Membrane Proteins / Q000276:immunology / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000276:immunology / Q000378:metabolism*; D008970:Molecular Weight; D009004:Monosaccharide Transport Proteins; D009842:Oligopeptides / Q000276:immunology; D011485:Protein Binding; D027981:Symporters
D029968:Escherichia coli Proteins; D005697:Galactosides; D006027:Glycosides; C050221:LacY protein, E coli; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D009004:Monosaccharide Transport Proteins; D009842:Oligopeptides; D027981:Symporters; C021499:lactose permease