title: Visualization of penicillin-binding proteins during sporulation of Streptomyces griseus.
abstract: We used fluorescein-tagged beta-lactam antibiotics to visualize penicillin-binding proteins (PBPs) in sporulating cultures of Streptomyces griseus. Six PBPs were identified in membranes prepared from growing and sporulating cultures. The binding activity of an 85-kDa PBP increased fourfold by 10 to 12 h of sporulation, at which time the sporulation septa were formed. Cefoxitin inhibited the interaction of the fluorescein-tagged antibiotics with the 85-kDa PBP and also prevented septum formation during sporulation but not during vegetative growth. The 85-kDa PBP, which was the predominant PBP in membranes of cells that were undergoing septation, preferentially bound fluorescein-6-aminopenicillanic acid (Flu-APA). Fluorescence microscopy showed that the sporulation septa were specifically labeled by Flu-APA; this interaction was blocked by prior exposure of the cells to cefoxitin at a concentration that interfered with septation. We hypothesize that the 85-kDa PBP is involved in septum formation during sporulation of S. griseus.
authors.affiliation: Department of Microbiology, Ohio State University, Columbus 43210, USA.
authors.forename: J
authors.initials: J
authors.lastname: Hao
authors.forename: K E
authors.initials: KE
authors.lastname: Kendrick
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology*; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000096:biosynthesis*; D002439:Cefotaxime / Q000494:pharmacology; D002440:Cefoxitin / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D006602:Hexosyltransferases; D007700:Kinetics; D008856:Microscopy, Fluorescence; D008970:Molecular Weight; D002267:Muramoylpentapeptide Carboxypeptidase / Q000096:biosynthesis*; D046915:Penicillin-Binding Proteins; D010406:Penicillins / Q000378:metabolism; D010458:Peptidyl Transferases; D013171:Spores, Bacterial / Q000187:drug effects / Q000502:physiology; D013305:Streptomyces griseus / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; D046915:Penicillin-Binding Proteins; D010406:Penicillins; D002440:Cefoxitin; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase; D002439:Cefotaxime