3P9K

Crystal structure of perennial ryegrass LpOMT1 complexed with S-adenosyl-L-homocysteine and coniferaldehyde


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.25 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.232 

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Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history


Literature

Structure-Function Analyses of a Caffeic Acid O-Methyltransferase from Perennial Ryegrass Reveal the Molecular Basis for Substrate Preference.

Louie, G.V.Bowman, M.E.Tu, Y.Mouradov, A.Spangenberg, G.Noel, J.P.

(2010) Plant Cell 22: 4114-4127

  • DOI: https://doi.org/10.1105/tpc.110.077578
  • Primary Citation of Related Structures:  
    3P9C, 3P9I, 3P9K

  • PubMed Abstract: 

    Lignin forms from the polymerization of phenylpropanoid-derived building blocks (the monolignols), whose modification through hydroxylation and O-methylation modulates the chemical and physical properties of the lignin polymer. The enzyme caffeic acid O-methyltransferase (COMT) is central to lignin biosynthesis. It is often targeted in attempts to engineer the lignin composition of transgenic plants for improved forage digestibility, pulping efficiency, or utility in biofuel production. Despite intensive investigation, the structural determinants of the regiospecificity and substrate selectivity of COMT remain poorly defined. Reported here are x-ray crystallographic structures of perennial ryegrass (Lolium perenne) COMT (Lp OMT1) in open conformational state, apo- and holoenzyme forms and, most significantly, in a closed conformational state complexed with the products S-adenosyl-L-homocysteine and sinapaldehyde. The product-bound complex reveals the post-methyl-transfer organization of COMT's catalytic groups with reactant molecules and the fully formed phenolic-ligand binding site. The core scaffold of the phenolic ligand forges a hydrogen-bonding network involving the 4-hydroxy group that anchors the aromatic ring and thereby permits only metahydroxyl groups to be positioned for transmethylation. While distal from the site of transmethylation, the propanoid tail substituent governs the kinetic preference of ryegrass COMT for aldehydes over alcohols and acids due to a single hydrogen bond donor for the C9 oxygenated moiety dictating the preference for an aldehyde.


  • Organizational Affiliation

    The Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, California 92037, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Caffeic acid O-methyltransferase
A, B, C, D
364Lolium perenneMutation(s): 0 
Gene Names: LpOMT1OMT1
EC: 2.1.1.6
UniProt
Find proteins for Q9ZTU2 (Lolium perenne)
Explore Q9ZTU2 
Go to UniProtKB:  Q9ZTU2
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9ZTU2
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.25 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.232 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 95.375α = 90
b = 85.062β = 111.75
c = 98.586γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling
CNSrefinement
PDB_EXTRACTdata extraction
BOSdata collection
CNSphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-01-12
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2023-09-06
    Changes: Data collection, Database references, Derived calculations, Refinement description