Anisodus acutangulus type III polyketide sythase AaPKS2 in complex with 4-carboxy-3-oxobutanoyl-CoA

Experimental Data Snapshot

  • Resolution: 2.53 Å
  • R-Value Free: 0.191 
  • R-Value Work: 0.166 
  • R-Value Observed: 0.167 

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This is version 1.2 of the entry. See complete history


Tropane alkaloids biosynthesis involves an unusual type III polyketide synthase and non-enzymatic condensation.

Huang, J.P.Fang, C.Ma, X.Wang, L.Yang, J.Luo, J.Yan, Y.Zhang, Y.Huang, S.X.

(2019) Nat Commun 10: 4036-4036

  • DOI: https://doi.org/10.1038/s41467-019-11987-z
  • Primary Citation of Related Structures:  
    6J1M, 6J1N

  • PubMed Abstract: 

    The skeleton of tropane alkaloids is derived from ornithine-derived N-methylpyrrolinium and two malonyl-CoA units. The enzymatic mechanism that connects N-methylpyrrolinium and malonyl-CoA units remains unknown. Here, we report the characterization of three pyrrolidine ketide synthases (PYKS), AaPYKS, DsPYKS, and AbPYKS, from three different hyoscyamine- and scopolamine-producing plants. By examining the crystal structure and biochemical activity of AaPYKS, we show that the reaction mechanism involves PYKS-mediated malonyl-CoA condensation to generate a 3-oxo-glutaric acid intermediate that can undergo non-enzymatic Mannich-like condensation with N-methylpyrrolinium to yield the racemic 4-(1-methyl-2-pyrrolidinyl)-3-oxobutanoic acid. This study therefore provides a long sought-after biosynthetic mechanism to explain condensation between N-methylpyrrolinium and acetate units and, more importantly, identifies an unusual plant type III polyketide synthase that can only catalyze one round of malonyl-CoA condensation.

  • Organizational Affiliation

    The Key Laboratory of Synthetic Biology, and CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A. acutangulus PKS2
A, B
427Anisodus acutangulusMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on B7X

Download Ideal Coordinates CCD File 
C [auth A],
D [auth B]
(3R,5R,9R)-1-[(2R,3S,4R,5R)-5-(6-amino-9H-purin-9-yl)-4-hydroxy-3-(phosphonooxy)tetrahydrofuran-2-yl]-3,5,9-trihydroxy-8,8-dimethyl-10,14,19,21-tetraoxo-2,4,6-trioxa-18-thia-11,15-diaza-3,5-diphosphatricosan-23-oic acid 3,5-dioxide (non-preferred name)
C26 H40 N7 O20 P3 S
Experimental Data & Validation

Experimental Data

  • Resolution: 2.53 Å
  • R-Value Free: 0.191 
  • R-Value Work: 0.166 
  • R-Value Observed: 0.167 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 108.347α = 90
b = 108.347β = 90
c = 191.485γ = 120
Software Package:
Software NamePurpose
HKL-2000data scaling
PDB_EXTRACTdata extraction
HKL-2000data reduction

Structure Validation

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Ligand Structure Quality Assessment 

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Natural Science Foundation of ChinaChina31822001

Revision History  (Full details and data files)

  • Version 1.0: 2019-09-11
    Type: Initial release
  • Version 1.1: 2019-09-25
    Changes: Data collection, Database references
  • Version 1.2: 2023-11-22
    Changes: Data collection, Database references, Refinement description