title: Assembly of an in vitro synthesized Escherichia coli outer membrane porin into its stable trimeric configuration.
abstract: The folding of in vitro synthesized outer membrane protein PhoE of Escherichia coli was studied in immunoprecipitation experiments with monoclonal antibodies which recognize cell surface-exposed conformational epitopes. The signal sequence appears to interfere with the formation of these conformational epitopes, since a mutant PhoE protein which lacks the majority of the signal peptide could be precipitated four times better than the wild type precursor. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the immunoprecipitated PhoE protein revealed that part of the immunoprecipitated PhoE was present as a heat-modifiable form of the protein which migrated faster in the gels than the completely denatured protein. This form of the protein probably represents a folded monomer which might be an intermediate in the assembly of the protein. Outer membrane vesicles were required to induce the formation of small amounts of heat-stable trimers, the functional form of the protein in vivo.
authors.affiliation: Institute of Molecular Biology and Medical Biotechnology, University of Utrecht, The Netherlands.
authors.forename: H
authors.initials: H
authors.lastname: de Cock
authors.forename: R
authors.initials: R
authors.lastname: Hendriks
authors.forename: T
authors.initials: T
authors.lastname: de Vrije
authors.forename: J
authors.initials: J
authors.lastname: Tommassen
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D006358:Hot Temperature; D007163:Immunosorbent Techniques; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation; D010957:Plasmids; D018272:Porins; D011487:Protein Conformation; D021382:Protein Sorting Signals / Q000235:genetics / Q000502:physiology
chemical_list: D001425:Bacterial Outer Membrane Proteins; D046911:Macromolecular Substances; D018272:Porins; D021382:Protein Sorting Signals