1D6F

CHALCONE SYNTHASE C164A MUTANT


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.69 Å
  • R-Value Free: 0.201 
  • R-Value Work: 0.182 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Dissection of malonyl-coenzyme A decarboxylation from polyketide formation in the reaction mechanism of a plant polyketide synthase.

Jez, J.M.Ferrer, J.L.Bowman, M.E.Dixon, R.A.Noel, J.P.

(2000) Biochemistry 39: 890-902

  • DOI: 10.1021/bi991489f
  • Primary Citation of Related Structures:  
    1D6F, 1D6H, 1D6I

  • PubMed Abstract: 
  • Chalcone synthase (CHS) catalyzes formation of the phenylpropanoid chalcone from one p-coumaroyl-CoA and three malonyl-coenzyme A (CoA) thioesters. The three-dimensional structure of CHS [Ferrer, J.-L., Jez, J. M., Bowman, M. E., Dixon, R. A., and Noel, J ...

    Chalcone synthase (CHS) catalyzes formation of the phenylpropanoid chalcone from one p-coumaroyl-CoA and three malonyl-coenzyme A (CoA) thioesters. The three-dimensional structure of CHS [Ferrer, J.-L., Jez, J. M., Bowman, M. E., Dixon, R. A., and Noel, J. P. (1999) Nat. Struct. Biol. 6, 775-784] suggests that four residues (Cys164, Phe215, His303, and Asn336) participate in the multiple decarboxylation and condensation reactions catalyzed by this enzyme. Here, we functionally characterize 16 point mutants of these residues for chalcone production, malonyl-CoA decarboxylation, and the ability to bind CoA and acetyl-CoA. Our results confirm Cys164's role as the active-site nucleophile in polyketide formation and elucidate the importance of His303 and Asn336 in the malonyl-CoA decarboxylation reaction. We suggest that Phe215 may help orient substrates at the active site during elongation of the polyketide intermediate. To better understand the structure-function relationships in some of these mutants, we also determined the crystal structures of the CHS C164A, H303Q, and N336A mutants refined to 1.69, 2.0, and 2.15 A resolution, respectively. The structure of the C164A mutant reveals that the proposed oxyanion hole formed by His303 and Asn336 remains undisturbed, allowing this mutant to catalyze malonyl-CoA decarboxylation without chalcone formation. The structures of the H303Q and N336A mutants support the importance of His303 and Asn336 in polarizing the thioester carbonyl of malonyl-CoA during the decarboxylation reaction. In addition, both of these residues may also participate in stabilizing the tetrahedral transition state during polyketide elongation. Conservation of the catalytic functions of the active-site residues may occur across a wide variety of condensing enzymes, including other polyketide and fatty acid synthases.


    Organizational Affiliation

    Structural Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
CHALCONE SYNTHASEA389Medicago sativaMutation(s): 1 
Gene Names: CHS2
EC: 2.3.1.74
UniProt
Find proteins for P30074 (Medicago sativa)
Explore P30074 
Go to UniProtKB:  P30074
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
B3P
Query on B3P

Download Ideal Coordinates CCD File 
C [auth A]2-[3-(2-HYDROXY-1,1-DIHYDROXYMETHYL-ETHYLAMINO)-PROPYLAMINO]-2-HYDROXYMETHYL-PROPANE-1,3-DIOL
C11 H26 N2 O6
HHKZCCWKTZRCCL-UHFFFAOYSA-N
 Ligand Interaction
SO4
Query on SO4

Download Ideal Coordinates CCD File 
B [auth A]SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.69 Å
  • R-Value Free: 0.201 
  • R-Value Work: 0.182 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 97.768α = 90
b = 97.768β = 90
c = 65.228γ = 120
Software Package:
Software NamePurpose
CCP4model building
REFMACrefinement
DENZOdata reduction
SCALEPACKdata scaling
CCP4phasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2000-02-03
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.3: 2018-01-31
    Changes: Experimental preparation