2RER

Crystal structure of the aromatase/cyclase domain of TcmN from Streptomyces glaucescens


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.215 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Crystal structure and functional analysis of tetracenomycin ARO/CYC: implications for cyclization specificity of aromatic polyketides.

Ames, B.D.Korman, T.P.Zhang, W.Smith, P.Vu, T.Tang, Y.Tsai, S.C.

(2008) Proc.Natl.Acad.Sci.Usa 105: 5349-5354

  • DOI: 10.1073/pnas.0709223105
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Polyketides are a class of natural products with highly diverse chemical structures and pharmaceutical activities. Polyketide cyclization, promoted by the aromatase/cyclase (ARO/CYC), helps diversify aromatic polyketides. How the ARO/CYC promotes hig ...

    Polyketides are a class of natural products with highly diverse chemical structures and pharmaceutical activities. Polyketide cyclization, promoted by the aromatase/cyclase (ARO/CYC), helps diversify aromatic polyketides. How the ARO/CYC promotes highly specific cyclization is not well understood because of the lack of a first-ring ARO/CYC structure. The 1.9 A crystal structure of Tcm ARO/CYC reveals that the enzyme belongs to the Bet v1-like superfamily (or STAR domain family) with a helix-grip fold, and contains a highly conserved interior pocket. Docking, mutagenesis, and an in vivo assay show that the size, shape, and composition of the pocket are important to orient and specifically fold the polyketide chain for C9-C14 first-ring and C7-C16 second-ring cyclizations. Two pocket residues, R69 and Y35, were found to be essential for promoting first- and second-ring cyclization specificity. Different pocket residue mutations affected the polyketide product distribution. A mechanism is proposed based on the structure-mutation-docking results. These results strongly suggest that the regiospecific cyclizations of the first two rings and subsequent aromatizations take place in the interior pocket. The chemical insights gleaned from this work pave the foundation toward defining the molecular rules for the ARO/CYC cyclization specificity, whose rational control will be important for future endeavors in the engineered biosynthesis of novel anticancer and antibiotic aromatic polyketides.


    Organizational Affiliation

    Department of Molecular Biology and Biochemistry, Department of Chemistry, University of California, Irvine, CA 92697, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Multifunctional cyclase-dehydratase-3-O-methyl transferase tcmN
A
173Streptomyces glaucescensMutation(s): 0 
Gene Names: tcmN
EC: 2.1.1.-
Find proteins for P16559 (Streptomyces glaucescens)
Go to UniProtKB:  P16559
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.215 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 69.660α = 90.00
b = 105.126β = 90.00
c = 50.259γ = 90.00
Software Package:
Software NamePurpose
CNSrefinement
DENZOdata reduction
SOLVEphasing
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-04-22
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance