Download MendeleySynthesis and Stereochemical Determination of the Peptide Antibiotic Novo29.
Krumberger, M., Li, X., Kreutzer, A.G., Peoples, A.J., Nitti, A.G., Cunningham, A.M., Jones, C.R., Achorn, C., Ling, L.L., Hughes, D.E., Nowick, J.S.(2023) J Org Chem 88: 2214-2220
- PubMed: 36655882
- DOI: https://doi.org/10.1021/acs.joc.2c02648
- Primary Citation of Related Structures:
8CUF, 8CUG - PubMed Abstract:
This paper describes the synthesis and stereochemical determination of Novo29 (clovibactin), a new peptide antibiotic that is related to teixobactin and is active against Gram-positive bacteria. Novo29 is an eight-residue depsipeptide that contains the noncanonical amino acid hydroxyasparagine of hitherto undetermined stereochemistry in a macrolactone ring. The amino acid building blocks Fmoc-(2 R ,3 R )-hydroxyasparagine-OH and Fmoc-(2 R ,3 S )-hydroxyasparagine-OH were synthesized from ( R , R )- and ( S , S )-diethyl tartrate. Novo29 and epi -Novo29 were then prepared by solid-phase peptide synthesis using these building blocks. Correlation with an authentic sample of Novo29 through 1 H NMR spectroscopy, LC-MS, and in vitro antibiotic activity established that Novo29 contains (2 R ,3 R )-hydroxyasparagine. X-ray crystallography reveals that epi -Novo29 adopts an amphiphilic conformation, with a hydrophobic surface and a hydrophilic surface. Four sets of epi -Novo29 molecules pack in the crystal lattice to form a hydrophobic core. The macrolactone ring adopts a conformation in which the main-chain amide NH groups converge to create a cavity, which binds ordered water and acetate anion. The amphiphilic conformation of epi -Novo29 is reminiscent of the amphiphilic conformation adopted by the related antibiotic teixobactin and its derivatives, which contains a hydrophobic surface that interacts with the lipids of the bacterial cell membrane and a hydrophilic surface that interacts with the aqueous environment. Molecular modeling suggests that Novo29 can adopt an amphiphilic conformation similar to teixobactin, suggesting that Novo29 may interact with bacteria in a similar fashion to teixobactin.
Organizational Affiliation:
Department of Chemistry, University of California, Irvine, Irvine, California92697, United States.
