title: Dissociation and reconstitution of membranes synthesizing the peptidoglycan of Bacillus megaterium. A protein factor for the polymerization step.
abstract: Cholate-solubilized Bacillus megaterium membranes can be reconstituted by dialysis in the presence of magnesium ion to regain approximately 12% of the original peptidoglycan synthetic activity. Bio-Gel A-5m filtration of the solubilized components shows that all of the compounds necessary for peptidoglycan synthesis can be dissociated into material with a molecular weight of less than approximately 68,000. Using this reconstitution system, an assay has been developed for a new protein factor, PG-II, of B. megaterium. This factor could be combined with phospho-N-acetylmuramyl pentapeptide translocase and N-acetylglucosaminyl transferase to synthesize polymerized peptidoglycan from the precursors UDP-N-acetylmuramyl pentapeptide and UDP-N-acetylglucosamine. In the absence of PG-II, the disaccharide pentapeptide substrate for the polymerase was accumulated. In the presence of this factor, the amount of the substrate was diminished and polymeric peptidoglycan was formed. Therefore, PG-II was likely to be necessary for the polymerization step and may well have been the polymerase itself. From three chromatographic steps developed for the purification of PG-II, it seemed likely that a single protein with a molecular weight of approximately 60,000 could have PG-II activity.
mesh_terms: D001410:Bacillus megaterium / Q000378:metabolism* / Q000648:ultrastructure; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D002793:Cholic Acids; D008274:Magnesium / Q000494:pharmacology; D010457:Peptidoglycan / Q000096:biosynthesis*; D011523:Protoplasts / Q000378:metabolism
chemical_list: D002793:Cholic Acids; D010457:Peptidoglycan; D008274:Magnesium