1FMI

CRYSTAL STRUCTURE OF HUMAN CLASS I ALPHA1,2-MANNOSIDASE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.222 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural basis for catalysis and inhibition of N-glycan processing class I alpha 1,2-mannosidases.

Vallee, F.Karaveg, K.Herscovics, A.Moremen, K.W.Howell, P.L.

(2000) J.Biol.Chem. 275: 41287-41298

  • DOI: 10.1074/jbc.M006927200
  • Primary Citation of Related Structures:  1FO2, 1FO3

  • PubMed Abstract: 
  • Endoplasmic reticulum (ER) class I alpha1,2-mannosidase (also known as ER alpha-mannosidase I) is a critical enzyme in the maturation of N-linked oligosaccharides and ER-associated degradation. Trimming of a single mannose residue acts as a signal to ...

    Endoplasmic reticulum (ER) class I alpha1,2-mannosidase (also known as ER alpha-mannosidase I) is a critical enzyme in the maturation of N-linked oligosaccharides and ER-associated degradation. Trimming of a single mannose residue acts as a signal to target misfolded glycoproteins for degradation by the proteasome. Crystal structures of the catalytic domain of human ER class I alpha1,2-mannosidase have been determined both in the presence and absence of the potent inhibitors kifunensine and 1-deoxymannojirimycin. Both inhibitors bind to the protein at the bottom of the active-site cavity, with the essential calcium ion coordinating the O-2' and O-3' hydroxyls and stabilizing the six-membered rings of both inhibitors in a (1)C(4) conformation. This is the first direct evidence of the role of the calcium ion. The lack of major conformational changes upon inhibitor binding and structural comparisons with the yeast alpha1, 2-mannosidase enzyme-product complex suggest that this class of inverting enzymes has a novel catalytic mechanism. The structures also provide insight into the specificity of this class of enzymes and provide a blueprint for the future design of novel inhibitors that prevent degradation of misfolded proteins in genetic diseases.


    Organizational Affiliation

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




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
ENDOPLASMIC RETICULUM ALPHA-MANNOSIDASE I
A
458Homo sapiensGene Names: MAN1B1
EC: 3.2.1.113
Find proteins for Q9UKM7 (Homo sapiens)
Go to Gene View: MAN1B1
Go to UniProtKB:  Q9UKM7
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
CA
Query on CA

Download SDF File 
Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.222 
  • Space Group: P 31 2 1
Unit Cell:
Length (Å)Angle (°)
a = 95.829α = 90.00
b = 95.829β = 90.00
c = 136.853γ = 120.00
Software Package:
Software NamePurpose
AMoREphasing
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2001-01-17
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance