title: The isotridecanyl side chain of plusbacin-A3 is essential for the transglycosylase inhibition of peptidoglycan biosynthesis.
abstract: Plusbacin-A3 (pb-A3) is a cyclic lipodepsipeptide that exhibits antibacterial activity against multidrug-resistant Gram-positive pathogens. Plusbacin-A3 is thought not to enter the cell cytoplasm, and its lipophilic isotridecanyl side chain is presumed to insert into the membrane bilayer, thereby facilitating either lipid II binding or some form of membrane disruption. Analogues of pb-A3, [(2)H]pb-A3 and deslipo-pb-A3, were synthesized to test membrane insertion as a key to the mode of action. [(2)H]pb-A3 has an isotopically (2)H-labeled isopropyl subunit of the lipid side chain, and deslipo-pb-A3 is missing the isotridecanyl side chain. Both analogues have the pb-A3 core structure. The loss of antimicrobial activity in deslipo-pb-A3 showed that the isotridecanyl side chain is crucial for the mode of action of the drug. However, rotational-echo double-resonance nuclear magnetic resonance characterization of [(2)H]pb-A3 bound to [1-(13)C]glycine-labeled whole cells of Staphylococcus aureus showed that the isotridecanyl side chain does not insert into the lipid membrane but instead is found in the staphylococcal cell wall, positioned near the pentaglycyl cross-bridge of the cell-wall peptidoglycan. Addition of [(2)H]pb-A3 during the growth of S. aureus resulted in the accumulation of Park's nucleotide, consistent with the inhibition of the transglycosylation step of peptidoglycan biosynthesis.
authors: Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States.
authors: Sung Joon
authors: SJ
authors: Kim
authors: Manmilan
authors: M
authors: Singh
authors: Aaron
authors: A
authors: Wohlrab
authors: Tsyr-Yan
authors: TY
authors: Yu
authors: Gary J
authors: GJ
authors: Patti
authors: Robert D
authors: RD
authors: O'Connor
authors: Michael
authors: M
authors: VanNieuwenhze
authors: Jacob
authors: J
authors: Schaefer
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D001424:Bacterial Infections / Q000188:drug therapy; D047630:Depsipeptides / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D010457:Peptidoglycan / Q000378:metabolism*; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*
chemical_list: D000890:Anti-Infective Agents; D047630:Depsipeptides; D004791:Enzyme Inhibitors; D010457:Peptidoglycan; C433785:plusbacin A3