5MGD

STRUCTURE OF E298Q-BETA-GALACTOSIDASE FROM ASPERGILLUS NIGER IN COMPLEX WITH 6-Galactosyl-lactose


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.191 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structural features of Aspergillus niger beta-galactosidase define its activity against glycoside linkages.

Rico-Diaz, A.Ramirez-Escudero, M.Vizoso-Vazquez, A.Cerdan, M.E.Becerra, M.Sanz-Aparicio, J.

(2017) FEBS J. 284: 1815-1829

  • DOI: 10.1111/febs.14083
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • β-Galactosidases are biotechnologically interesting enzymes that catalyze the hydrolysis or transgalactosylation of β-galactosides. Among them, the Aspergillus niger β-galactosidase (AnβGal) belongs to the glycoside hydrolase family 35 (GH35) and is ...

    β-Galactosidases are biotechnologically interesting enzymes that catalyze the hydrolysis or transgalactosylation of β-galactosides. Among them, the Aspergillus niger β-galactosidase (AnβGal) belongs to the glycoside hydrolase family 35 (GH35) and is widely used in the industry due to its high hydrolytic activity which is used to degrade lactose. We present here its three-dimensional structure in complex with different oligosaccharides, to illustrate the structural determinants of the broad specificity of the enzyme against different glycoside linkages. Remarkably, the residues Phe264, Tyr304, and Trp806 make a dynamic hydrophobic platform that accommodates the sugar at subsite +1 suggesting a main role on the recognition of structurally different substrates. Moreover, complexes with the trisaccharides show two potential subsites +2 depending on the substrate type. This feature and the peculiar shape of its wide cavity suggest that AnβGal might accommodate branched substrates from the complex net of polysaccharides composing the plant material in its natural environment. Relevant residues were selected and mutagenesis analyses were performed to evaluate their role in the catalytic performance and the hydrolase/transferase ratio of AnβGal. Thus, we generated mutants with improved transgalactosylation activity. In particular, the variant Y304F/Y355H/N357G/W806F displays a higher level of galacto-oligosaccharides production than the Aspergillus oryzae β-galactosidase, which is the preferred enzyme in the industry owing to its high transferase activity. Our results provide new knowledge on the determinants modulating specificity and the catalytic performance of fungal GH35 β-galactosidases. In turn, this fundamental background gives novel tools for the future improvement of these enzymes, which represent an interesting target for rational design.


    Organizational Affiliation

    Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Bioloxía, Facultade de Ciencias, Universidade da Coruña, Spain.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Probable beta-galactosidase A
A
1013Aspergillus niger (strain CBS 513.88 / FGSC A1513)Mutation(s): 1 
Gene Names: lacA
EC: 3.2.1.23
Find proteins for A2QAN3 (Aspergillus niger (strain CBS 513.88 / FGSC A1513))
Go to UniProtKB:  A2QAN3
Small Molecules
Ligands 8 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CL
Query on CL

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A
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
MAN
Query on MAN

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A
ALPHA-D-MANNOSE
C6 H12 O6
WQZGKKKJIJFFOK-PQMKYFCFSA-N
 Ligand Interaction
GAL
Query on GAL

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A
BETA-D-GALACTOSE
C6 H12 O6
WQZGKKKJIJFFOK-FPRJBGLDSA-N
 Ligand Interaction
BMA
Query on BMA

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A
BETA-D-MANNOSE
C6 H12 O6
WQZGKKKJIJFFOK-RWOPYEJCSA-N
 Ligand Interaction
GLC
Query on GLC

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A
ALPHA-D-GLUCOSE
C6 H12 O6
WQZGKKKJIJFFOK-DVKNGEFBSA-N
 Ligand Interaction
DMS
Query on DMS

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A
DIMETHYL SULFOXIDE
C2 H6 O S
IAZDPXIOMUYVGZ-UHFFFAOYSA-N
 Ligand Interaction
NAG
Query on NAG

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A
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
1PE
Query on 1PE

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A
PENTAETHYLENE GLYCOL
PEG400
C10 H22 O6
JLFNLZLINWHATN-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.191 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 58.285α = 90.00
b = 105.873β = 99.24
c = 83.715γ = 90.00
Software Package:
Software NamePurpose
XDSdata reduction
Aimlessdata scaling
MOLREPphasing
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2017-04-19
    Type: Initial release
  • Version 1.1: 2017-06-28
    Type: Database references