1KKT

Structure of P. citrinum alpha 1,2-mannosidase reveals the basis for differences in specificity of the ER and Golgi Class I enzymes


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.193 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure of Penicillium citrinum alpha 1,2-mannosidase reveals the basis for differences in specificity of the endoplasmic reticulum and Golgi class I enzymes.

Lobsanov, Y.D.Vallee, F.Imberty, A.Yoshida, T.Yip, P.Herscovics, A.Howell, P.L.

(2002) J.Biol.Chem. 277: 5620-5630

  • DOI: 10.1074/jbc.M110243200
  • Primary Citation of Related Structures:  1KRE, 1KRF

  • PubMed Abstract: 
  • Class I alpha1,2-mannosidases (glycosylhydrolase family 47) are key enzymes in the maturation of N-glycans. This protein family includes two distinct enzymatically active subgroups. Subgroup 1 includes the yeast and human endoplasmic reticulum (ER) a ...

    Class I alpha1,2-mannosidases (glycosylhydrolase family 47) are key enzymes in the maturation of N-glycans. This protein family includes two distinct enzymatically active subgroups. Subgroup 1 includes the yeast and human endoplasmic reticulum (ER) alpha1,2-mannosidases that primarily trim Man(9)GlcNAc(2) to Man(8)GlcNAc(2) isomer B whereas subgroup 2 includes mammalian Golgi alpha1,2-mannosidases IA, IB, and IC that trim Man(9)GlcNAc(2) to Man(5)GlcNAc(2) via Man(8)GlcNAc(2) isomers A and C. The structure of the catalytic domain of the subgroup 2 alpha1,2-mannosidase from Penicillium citrinum has been determined by molecular replacement at 2.2-A resolution. The fungal alpha1,2-mannosidase is an (alphaalpha)(7)-helix barrel, very similar to the subgroup 1 yeast (Vallée, F., Lipari, F., Yip, P., Sleno, B., Herscovics, A., and Howell, P. L. (2000) EMBO J. 19, 581-588) and human (Vallée, F., Karaveg, K., Herscovics, A., Moremen, K. W., and Howell, P. L. (2000) J. Biol. Chem. 275, 41287-41298) ER enzymes. The location of the conserved acidic residues of the catalytic site and the binding of the inhibitors, kifunensine and 1-deoxymannojirimycin, to the essential calcium ion are conserved in the fungal enzyme. However, there are major structural differences in the oligosaccharide binding site between the two alpha1,2-mannosidase subgroups. In the subgroup 1 enzymes, an arginine residue plays a critical role in stabilizing the oligosaccharide substrate. In the fungal alpha1,2-mannosidase this arginine is replaced by glycine. This replacement and other sequence variations result in a more spacious carbohydrate binding site. Modeling studies of interactions between the yeast, human and fungal enzymes with different Man(8)GlcNAc(2) isomers indicate that there is a greater degree of freedom to bind the oligosaccharide in the active site of the fungal enzyme than in the yeast and human ER alpha1,2-mannosidases.


    Organizational Affiliation

    Program in Structural Biology and Biochemistry, Research Institute, The Hospital for Sick Children, 555 University Ave., Toronto, Ontario M5G 1X8, Canada.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Mannosyl-oligosaccharide alpha-1,2-mannosidase
A, B
511Penicillium citrinumGene Names: MSDC
EC: 3.2.1.113
Find proteins for P31723 (Penicillium citrinum)
Go to UniProtKB:  P31723
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download SDF File 
Download CCD File 
A, B
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
MAN
Query on MAN

Download SDF File 
Download CCD File 
A, B
ALPHA-D-MANNOSE
C6 H12 O6
WQZGKKKJIJFFOK-PQMKYFCFSA-N
 Ligand Interaction
NAG
Query on NAG

Download SDF File 
Download CCD File 
A, B
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.193 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 56.487α = 90.00
b = 110.997β = 99.17
c = 86.235γ = 90.00
Software Package:
Software NamePurpose
CNSrefinement
DENZOdata reduction
CNSphasing
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2002-01-23
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Non-polymer description, Version format compliance