Crystal structure of OxaG

Experimental Data Snapshot

  • Resolution: 1.99 Å
  • R-Value Free: 0.260 
  • R-Value Work: 0.220 
  • R-Value Observed: 0.222 

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This is version 1.5 of the entry. See complete history


Unveiling sequential late-stage methyltransferase reactions in the meleagrin/oxaline biosynthetic pathway.

Newmister, S.A.Romminger, S.Schmidt, J.J.Williams, R.M.Smith, J.L.Berlinck, R.G.S.Sherman, D.H.

(2018) Org Biomol Chem 16: 6450-6459

  • DOI: https://doi.org/10.1039/c8ob01565a
  • Primary Citation of Related Structures:  
    5W7K, 5W7M, 5W7P, 5W7R, 5W7S

  • PubMed Abstract: 

    Antimicrobial and anti-proliferative meleagrin and oxaline are roquefortine C-derived alkaloids produced by fungi of the genus Penicillium. Tandem O-methylations complete the biosynthesis of oxaline from glandicoline B through meleagrin. Currently, little is known about the role of these methylation patterns in the bioactivity profile of meleagrin and oxaline. To establish the structural and mechanistic basis of methylation in these pathways, crystal structures were determined for two late-stage methyltransferases in the oxaline and meleagrin gene clusters from Penicillium oxalicum and Penicillium chrysogenum. The homologous enzymes OxaG and RoqN were shown to catalyze penultimate hydroxylamine O-methylation to generate meleagrin in vitro. Crystal structures of these enzymes in the presence of methyl donor S-adenosylmethionine revealed an open active site, which lacks an apparent base indicating that catalysis is driven by proximity effects. OxaC was shown to methylate meleagrin to form oxaline in vitro, the terminal pathway product. Crystal structures of OxaC in a pseudo-Michaelis complex containing sinefungin and meleagrin, and in a product complex containing S-adenosyl-homocysteine and oxaline, reveal key active site residues with His313 serving as a base that is activated by Glu369. These data provide structural insights into the enzymatic methylation of these alkaloids that include a rare hydroxylamine oxygen acceptor, and can be used to guide future efforts towards selective derivatization and structural diversification and establishing the role of methylation in bioactivity.

  • Organizational Affiliation

    Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, USA. davidhs@umich.edu.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
312Penicillium oxalicumMutation(s): 0 
Find proteins for A0A1B2TT18 (Penicillium oxalicum)
Explore A0A1B2TT18 
Go to UniProtKB:  A0A1B2TT18
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A1B2TT18
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.99 Å
  • R-Value Free: 0.260 
  • R-Value Work: 0.220 
  • R-Value Observed: 0.222 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 121.628α = 90
b = 36.208β = 102.83
c = 126.304γ = 90
Software Package:
Software NamePurpose
XSCALEdata scaling
XDSdata processing
PDB_EXTRACTdata extraction
XDSdata collection

Structure Validation

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Ligand Structure Quality Assessment 

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Cancer Institute (NIH/NCI)United StatesCA070375
National Science Foundation (NSF, United States)United StatesCHE 1220121
Sao Paulo Research Foundation (FAPESP)Brazil2012/50026-3
Sao Paulo Research Foundation (FAPESP)Brazil2013/50228-8
Sao Paulo Research Foundation (FAPESP)Brazil2014/05670-7
CAPESBrazilBEX 4498/14-3

Revision History  (Full details and data files)

  • Version 1.0: 2018-06-27
    Type: Initial release
  • Version 1.1: 2018-09-05
    Changes: Data collection, Database references
  • Version 1.2: 2018-09-26
    Changes: Data collection, Database references
  • Version 1.3: 2019-04-17
    Changes: Author supporting evidence, Data collection
  • Version 1.4: 2019-11-27
    Changes: Author supporting evidence
  • Version 1.5: 2024-03-13
    Changes: Data collection, Database references