title: Isolation and characterization of the outer membrane from Vibrio parahaemolyticus.
abstract: The outer membrane of Vibrio parahaemolyticus strain 3283-61 (serotype O2:K3) was isolated from blebs released upon spheroplast formation, in the presence of lysozyme and EDTA, by isopycnic sucrose density gradient centrifugation. SDS-PAGE of the outer membrane fraction prepared from cells grown in nutrient broth containing 3% (w/v) NaCl revealed five major proteins, designated a to e, with apparent approximate molecular weights: a, 44 000; b, 36 000; c, 33 500; d, 26 500; e, 22 000. An increase in NaCl concentration in the growth medium resulted in an increase of proteins b and c, whereas a decrease to 0.5% (w/v) induced two additional major proteins with respective molecular weights of about 35 000 and 32 000. Proteins a and b appeared to be loosely associated with the peptidoglycan layer since they were largely retained after extraction with 2% (w/v) SDS at 50 degrees C for 30 min. Proteins c and/or e may play a role in phage VP1-receptors since phage-resistant mutants derived from strain 3283-61 had significantly diminished amounts of both proteins. The major outer membrane proteins varied in number and molecular weight in strains of V. parahaemolyticus belonging to different K-serotypes.
mesh_terms: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000032:analysis*; D002462:Cell Membrane / Q000032:analysis / Q000648:ultrastructure; D002473:Cell Wall / Q000032:analysis; D002500:Centrifugation, Isopycnic; D004591:Electrophoresis, Polyacrylamide Gel; D008565:Membrane Proteins / Q000032:analysis*; D008854:Microscopy, Electron; D008970:Molecular Weight; D009154:Mutation; D013045:Species Specificity; D014736:Vibrio parahaemolyticus / Q000032:analysis* / Q000648:ultrastructure
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D008565:Membrane Proteins