3KRG

Structural insights into substrate specificity and the anti beta-elimination mechanism of pectate lyase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.196 
  • R-Value Work: 0.132 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structural insights into substrate specificity and the anti beta-elimination mechanism of pectate lyase

Seyedarabi, A.To, T.T.Ali, S.Hussain, S.Fries, M.Madsen, R.Clausen, M.H.Teixteira, S.Brocklehurst, K.Pickersgill, R.W.

(2010) Biochemistry 49: 539-546

  • DOI: 10.1021/bi901503g
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Pectate lyases harness anti beta-elimination chemistry to cleave the alpha-1,4 linkage in the homogalacturonan region of plant cell wall pectin. We have studied the binding of five pectic oligosaccharides to Bacillus subtilis pectate lyase in crystal ...

    Pectate lyases harness anti beta-elimination chemistry to cleave the alpha-1,4 linkage in the homogalacturonan region of plant cell wall pectin. We have studied the binding of five pectic oligosaccharides to Bacillus subtilis pectate lyase in crystals of the inactive enzyme in which the catalytic base is substituted with alanine (R279A). We discover that the three central subsites (-1, +1, and +2) have a profound preference for galacturonate but that the distal subsites can accommodate methylated galacturonate. It is reasonable to assume therefore that pectate lyase can cleave pectin with three consecutive galacturonate residues. The enzyme in the absence of substrate binds a single calcium ion, and we show that two additional calcium ions bind between enzyme and substrate carboxylates occupying the +1 subsite in the Michaelis complex. The substrate binds less intimately to the enzyme in a complex made with a catalytic base in place but in the absence of the calcium ions and an adjacent lysine. In this complex, the catalytic base is correctly positioned to abstract the C5 proton, but there are no calcium ions binding the carboxylate at the +1 subsite. It is clear, therefore, that the catalytic calcium ions and adjacent lysine promote catalysis by acidifying the alpha-proton, facilitating its abstraction by the base. There is also clear evidence that binding distorts the relaxed 2(1) or 3(1) helical conformation of the oligosaccharides in the region of the scissile bond.


    Organizational Affiliation

    School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Pectate lyase
A
399Bacillus subtilis (strain 168)Mutation(s): 3 
Gene Names: pel
EC: 4.2.2.2
Find proteins for P39116 (Bacillus subtilis (strain 168))
Go to UniProtKB:  P39116
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GOL
Query on GOL

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Download CCD File 
A
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
CO
Query on CO

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Download CCD File 
A
COBALT (II) ION
Co
XLJKHNWPARRRJB-UHFFFAOYSA-N
 Ligand Interaction
ADA
Query on ADA

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Download CCD File 
A
ALPHA-D-GALACTOPYRANURONIC ACID
ALPHA D-GALACTURONIC ACID
C6 H10 O7
AEMOLEFTQBMNLQ-BKBMJHBISA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.196 
  • R-Value Work: 0.132 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 50.626α = 90.00
b = 69.066β = 113.85
c = 59.656γ = 90.00
Software Package:
Software NamePurpose
SCALAdata scaling
MOSFLMdata reduction
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-02-09
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance