4KCB

Crystal Structure of Exo-1,5-alpha-L-arabinanase from Bovine Ruminal Metagenomic Library


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.9 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.217 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Mechanistic strategies for catalysis adopted by evolutionary distinct family 43 arabinanases.

Santos, C.R.Polo, C.C.Costa, M.C.Nascimento, A.F.Meza, A.N.Cota, J.Hoffmam, Z.B.Honorato, R.V.Oliveira, P.S.Goldman, G.H.Gilbert, H.J.Prade, R.A.Ruller, R.Squina, F.M.Wong, D.W.Murakami, M.T.

(2014) J.Biol.Chem. 289: 7362-7373

  • DOI: 10.1074/jbc.M113.537167
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Arabinanases (ABNs, EC 3.2.1.99) are promising catalysts for environmentally friendly biomass conversion into energy and chemicals. These enzymes catalyze the hydrolysis of the α-1,5-linked L-arabinofuranoside backbone of plant cell wall arabinans re ...

    Arabinanases (ABNs, EC 3.2.1.99) are promising catalysts for environmentally friendly biomass conversion into energy and chemicals. These enzymes catalyze the hydrolysis of the α-1,5-linked L-arabinofuranoside backbone of plant cell wall arabinans releasing arabino-oligosaccharides and arabinose, the second most abundant pentose in nature. In this work, new findings about the molecular mechanisms governing activation, functional differentiation, and catalysis of GH43 ABNs are presented. Biophysical, mutational, and biochemical studies with the hyperthermostable two-domain endo-acting ABN from Thermotoga petrophila (TpABN) revealed how some GH43 ABNs are activated by calcium ions via hyperpolarization of the catalytically relevant histidine and the importance of the ancillary domain for catalysis and conformational stability. On the other hand, the two GH43 ABNs from rumen metagenome, ARN2 and ARN3, presented a calcium-independent mechanism in which sodium is the most likely substituent for calcium ions. The crystal structure of the two-domain endo-acting ARN2 showed that its ability to efficiently degrade branched substrates is due to a larger catalytic interface with higher accessibility than that observed in other ABNs with preference for linear arabinan. Moreover, crystallographic characterization of the single-domain exo-acting ARN3 indicated that its cleavage pattern producing arabinose is associated with the chemical recognition of the reducing end of the substrate imposed by steric impediments at the aglycone-binding site. By structure-guided rational design, ARN3 was converted into a classical endo enzyme, confirming the role of the extended Arg(203)-Ala(230) loop in determining its action mode. These results reveal novel molecular aspects concerning the functioning of GH43 ABNs and provide new strategies for arabinan degradation.


    Organizational Affiliation

    From the Brazilian Biosciences National Laboratory and.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Arabinan endo-1,5-alpha-L-arabinosidase
A, B
447uncultured bacteriumMutation(s): 0 
Find proteins for D2XML8 (uncultured bacterium)
Go to UniProtKB:  D2XML8
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PO4
Query on PO4

Download SDF File 
Download CCD File 
A, B
PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.9 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.217 
  • Space Group: P 63 2 2
Unit Cell:
Length (Å)Angle (°)
a = 140.115α = 90.00
b = 140.115β = 90.00
c = 159.011γ = 120.00
Software Package:
Software NamePurpose
MOLREPphasing
HKL-2000data reduction
MAR345dtbdata collection
REFMACrefinement
HKL-2000data scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2014-02-05
    Type: Initial release
  • Version 1.1: 2014-04-09
    Type: Database references