The mechanism of wall synthesis in bacteria. The organization of enzymes and isoprenoid phosphates in the membrane

Abstract

1. The synthesis of peptidoglycan and teichoic acids by cell-free preparations from Bacillus licheniformis A.T.C.C. 9945 and Bacillus subtilis N.C.T.C. 3610 has been studied under a variety of conditions. 2. It was shown that poly(glycerol phosphate) is synthesized through a lipid intermediate, and it is concluded from this and other work that all major bacterial wall polymers are formed in a similar manner through such intermediates. 3. Close interrelation between the synthesis of peptidoglycan and teichoic acids was demonstrated, and inhibition studies confirm that the polyprenol phosphate molecules participating in the synthesis of peptidoglycan are shared with the systems that synthesize teichoic acids. 4. Nucleotides for the synthesis of one polymer are inhibitory towards synthesis of the other, and these effects can be enhanced or diminished by preincubation of the enzyme system with appropriate nucleotide precursors. 5. It is concluded that the return of undecaprenol phosphate to a common pool occurs only after the completion of polymer chains, and not after each cycle in the attachment of individual repeating units. This and other observations support a model for bacterial wall synthesis in which the multi-enzyme systems for each polymer are closely aligned in the membrane, with a molecule of undecaprenol phosphate located between them in a manner that enables it to be shared. The general mechanisms of wall synthesis and its control are discussed.

Biosynthesis of teichoic acid in micrococcus varians ATCC 29750

“…Evidence for this comes from earlier studies on the chemistry of lipids labelled during teichoic acid biosynthesis [lo,1 l], the interdependence of peptidoglycan and teichoic acid synthesis and their inhibition by bacitracin [ 12,131, and more recently the sensitivity of linkage unit synthesis to the antibiotic tunicamycin [4-71. Tunicamycin inhibits specifically the transfer of N-acetylglucosamine 3 -phosphate from its uridine nucleotide to polyprenyl phosphate [ 141, the initial reaction (a) in the scheme.…”

The role of phosphatidylglycerol in the in vitro biosynthesis of teichoic acid and lipoteichoic acid

“…Based on indirect evidence, Anderson et al [2] suggested the involvement of glycosylpolyisoprenylphosphate intermediate in the biosynthesis of teichoic acid. However, the in vivo pulsechase experiments done in our laboratory [3,4] and Glaser's laboratory [5] suggested that phosphatidylglycerol [PG] is the precursor in lipoteichoic acid biosynthesis.…”

Biosynthesis of the linkage unit joining peptidoglycan to poly(N‐acetylglucosamine 1‐phosphate) in walls ofMicrococcus varians ATCC 29750

“…[/3-aZP]CDP-[2-all]glycerol was prepared by mixing appropriate amounts of the singly-labelled substrates to give an isotopic ratio (3H : a2p) of about 4:1. This doublylabelled material was repurified by paper chromatography [16] and assayed immediately before use. Cells of Micrococcus varians ATCC 29750 were grown and membranes prepared therefrom as in [6,17].…”

“…CDP-glycerol, CDP-[2-3H]glycerol and [/3-32p]CDPglycerol were prepared as in [6,15,16]. [/3-aZP]CDP-[2-all]glycerol was prepared by mixing appropriate amounts of the singly-labelled substrates to give an isotopic ratio (3H : a2p) of about 4:1.…”