4PMV

Crystal structure of a novel reducing-end xylose-releasing exo-oligoxylanase (XynA) belonging to GH10 family (space group P43212)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.001 Å
  • R-Value Free: 0.253 
  • R-Value Work: 0.226 

wwPDB Validation 3D Report Full Report


This is version 1.5 of the entry. See complete history

Literature

Molecular mechanisms associated with xylan degradation by xanthomonas plant pathogens.

Santos, C.R.Hoffmam, Z.B.de Matos Martins, V.P.Zanphorlin, L.M.de Paula Assis, L.H.Honorato, R.V.Lopes de Oliveira, P.S.Ruller, R.Murakami, M.T.

(2014) J.Biol.Chem. 289: 32186-32200

  • DOI: 10.1074/jbc.M114.605105
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Xanthomonas pathogens attack a variety of economically relevant plants, and their xylan CUT system (carbohydrate utilization with TonB-dependent outer membrane transporter system) contains two major xylanase-related genes, xynA and xynB, which influe ...

    Xanthomonas pathogens attack a variety of economically relevant plants, and their xylan CUT system (carbohydrate utilization with TonB-dependent outer membrane transporter system) contains two major xylanase-related genes, xynA and xynB, which influence biofilm formation and virulence by molecular mechanisms that are still elusive. Herein, we demonstrated that XynA is a rare reducing end xylose-releasing exo-oligoxylanase and not an endo-β-1,4-xylanase as predicted. Structural analysis revealed that an insertion in the β7-α7 loop induces dimerization and promotes a physical barrier at the +2 subsite conferring this unique mode of action within the GH10 family. A single mutation that impaired dimerization became XynA active against xylan, and high endolytic activity was achieved when this loop was tailored to match a canonical sequence of endo-β-1,4-xylanases, supporting our mechanistic model. On the other hand, the divergent XynB proved to be a classical endo-β-1,4-xylanase, despite the low sequence similarity to characterized GH10 xylanases. Interestingly, this enzyme contains a calcium ion bound nearby to the glycone-binding region, which is required for catalytic activity and structural stability. These results shed light on the molecular basis for xylan degradation by Xanthomonas and suggest how these enzymes synergistically assist infection and pathogenesis. Our findings indicate that XynB contributes to breach the plant cell wall barrier, providing nutrients and facilitating the translocation of effector molecules, whereas the exo-oligoxylanase XynA possibly participates in the suppression of oligosaccharide-induced immune responses.


    Organizational Affiliation

    From the Biosciences National Laboratory and.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Endo-1,4-beta-xylanase A
A, B
357Xanthomonas axonopodis pv. citri (strain 306)Mutation(s): 0 
Gene Names: xynA
EC: 3.2.1.8
Find proteins for Q8PEU1 (Xanthomonas axonopodis pv. citri (strain 306))
Go to UniProtKB:  Q8PEU1
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.001 Å
  • R-Value Free: 0.253 
  • R-Value Work: 0.226 
  • Space Group: P 43 21 2
Unit Cell:
Length (Å)Angle (°)
a = 78.819α = 90.00
b = 78.819β = 90.00
c = 303.969γ = 90.00
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
REFMACrefinement
HKL-2000data reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Sao Paulo Research FoundationBrazil13/13309-0

Revision History 

  • Version 1.0: 2014-10-08
    Type: Initial release
  • Version 1.1: 2014-10-15
    Type: Database references, Structure summary
  • Version 1.2: 2014-11-26
    Type: Database references
  • Version 1.3: 2017-11-01
    Type: Author supporting evidence, Database references, Derived calculations, Other, Source and taxonomy, Structure summary
  • Version 1.4: 2019-02-13
    Type: Data collection, Source and taxonomy
  • Version 1.5: 2019-04-17
    Type: Author supporting evidence, Data collection