Crystal complex of N-terminal Human Maltase-Glucoamylase with NR4-8

Experimental Data Snapshot

  • Resolution: 1.90 Å
  • R-Value Free: 0.244 
  • R-Value Work: 0.205 
  • R-Value Observed: 0.207 

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New glucosidase inhibitors from an ayurvedic herbal treatment for type 2 diabetes: structures and inhibition of human intestinal maltase-glucoamylase with compounds from Salacia reticulata.

Sim, L.Jayakanthan, K.Mohan, S.Nasi, R.Johnston, B.D.Pinto, B.M.Rose, D.R.

(2010) Biochemistry 49: 443-451

  • DOI: https://doi.org/10.1021/bi9016457
  • Primary Citation of Related Structures:  
    3L4T, 3L4U, 3L4V, 3L4W, 3L4X, 3L4Y, 3L4Z

  • PubMed Abstract: 

    An approach to controlling blood glucose levels in individuals with type 2 diabetes is to target alpha-amylases and intestinal glucosidases using alpha-glucosidase inhibitors acarbose and miglitol. One of the intestinal glucosidases targeted is the N-terminal catalytic domain of maltase-glucoamylase (ntMGAM), one of the four intestinal glycoside hydrolase 31 enzyme activities responsible for the hydrolysis of terminal starch products into glucose. Here we present the X-ray crystallographic studies of ntMGAM in complex with a new class of alpha-glucosidase inhibitors derived from natural extracts of Salacia reticulata, a plant used traditionally in Ayuverdic medicine for the treatment of type 2 diabetes. Included in these extracts are the active compounds salacinol, kotalanol, and de-O-sulfonated kotalanol. This study reveals that de-O-sulfonated kotalanol is the most potent ntMGAM inhibitor reported to date (K(i) = 0.03 microM), some 2000-fold better than the compounds currently used in the clinic, and highlights the potential of the salacinol class of inhibitors as future drug candidates.

  • Organizational Affiliation

    Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, 101 College Street, Toronto, ON, M5G 1L7 Canada.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Maltase-glucoamylase, intestinal875Homo sapiensMutation(s): 1 
EC: (PDB Primary Data), (PDB Primary Data)
UniProt & NIH Common Fund Data Resources
Find proteins for O43451 (Homo sapiens)
Explore O43451 
Go to UniProtKB:  O43451
PHAROS:  O43451
GTEx:  ENSG00000257335 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO43451
Sequence Annotations
  • Reference Sequence


Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
Glycosylation Resources
GlyTouCan:  G42666HT
GlyCosmos:  G42666HT
GlyGen:  G42666HT
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
NR3 Binding MOAD:  3L4X Ki: 130 (nM) from 1 assay(s)
PDBBind:  3L4X Ki: 130 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 1.90 Å
  • R-Value Free: 0.244 
  • R-Value Work: 0.205 
  • R-Value Observed: 0.207 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 87.173α = 90
b = 109.437β = 90
c = 109.327γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-02-09
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-11-01
    Changes: Refinement description
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Database references, Derived calculations, Structure summary