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Title: Insights into Methyltransferase Specificity and Bioactivity of Derivatives of the Antibiotic Plantazolicin

Peptide antibiotics represent a class of conformationally-constrained natural products of growing pharmaceutical interest. Plantazolicin (PZN) is a linear, polyheterocyclic natural product with highly selective and potent activity against the anthrax-causing bacterium, Bacillus anthracis. The bioactivity of PZN is contingent on dimethylation of its N-terminal Arg residue by an S-adenosylmethionine-dependent methyltransferase. Here in this paper, we explore the substrate tolerances of two homologous PZN methyltransferases by carrying out kinetic analyses of the enzymes against a synthetic panel of truncated PZN analogs containing the N-terminal Arg residue. X-ray cocrystal structures of the PZN methyltransferases with each of these heterocycle-containing substrates provide a rationale for understanding the strict substrate specificity of these enzymes. Kinetic studies of structure-guided, site-specific variants allowed for the assignment of residues governing catalysis and substrate scope. Microbiological testing further revealed that upon dimethylation of the N-terminal Arg, a pentaheterocyclized PZN analog retained potent anti-B. anthracis activity, nearly equal to that of full-length PZN. These studies may be useful in the biosynthetic engineering of natural product analogs with different bioactivity profiles, as demonstrated by our identification of a truncated plantazolicin derivative that is active against methicillin-resistant Staphylococcus aureus (MRSA).
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [4]
  1. Univ. of Illinois, Urbana-Champaign, IL (United States). Dept. of Biochemistry
  2. Univ. of Illinois, Urbana-Champaign, IL (United States). Dept. of Chemistry
  3. Univ. of Illinois, Urbana-Champaign, IL (United States). Dept. of Chemistry; Univ. of Illinois, Urbana-Champaign, IL (United States). Dept. of Microbiology; Univ. of Illinois, Urbana-Champaign, IL (United States). Inst. for Genomic Biology
  4. Univ. of Illinois, Urbana-Champaign, IL (United States). Dept. of Biochemistry; Univ. of Illinois, Urbana-Champaign, IL (United States). Dept. of Chemistry; Univ. of Illinois, Urbana-Champaign, IL (United States). Inst. for Genomic Biology; Univ. of Illinois, Urbana-Champaign, IL (United States). Center for Biophysics and Computational Biology
Publication Date:
OSTI Identifier:
1182773
Grant/Contract Number:
AC02-06CH11357; S10 RR027109; DP2 OD008463
Type:
Accepted Manuscript
Journal Name:
ACS Chemical Biology
Additional Journal Information:
Journal Volume: 10; Journal Issue: 5; Journal ID: ISSN 1554-8929
Publisher:
American Chemical Society (ACS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org:
USDOE; National Institutes of Health (NIH)
Country of Publication:
United States
Language:
ENGLISH
Subject:
59 BASIC BIOLOGICAL SCIENCES; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY