3LPO

Crystal structure of the N-terminal domain of sucrase-isomaltase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.20 Å
  • R-Value Free: 0.251 
  • R-Value Work: 0.225 
  • R-Value Observed: 0.227 

wwPDB Validation   3D Report Full Report



Literature

Structural basis for substrate selectivity in human maltase-glucoamylase and sucrase-isomaltase N-terminal domains.

Sim, L.Willemsma, C.Mohan, S.Naim, H.Y.Pinto, B.M.Rose, D.R.

(2010) J Biol Chem 285: 17763-17770

  • DOI: 10.1074/jbc.M109.078980
  • Primary Citation of Related Structures:  
    3LPO, 3LPP

  • PubMed Abstract: 
  • Human maltase-glucoamylase (MGAM) and sucrase-isomaltase (SI) are small intestinal enzymes that work concurrently to hydrolyze the mixture of linear alpha-1,4- and branched alpha-1,6-oligosaccharide substrates that typically make up terminal starch diges ...

    Human maltase-glucoamylase (MGAM) and sucrase-isomaltase (SI) are small intestinal enzymes that work concurrently to hydrolyze the mixture of linear alpha-1,4- and branched alpha-1,6-oligosaccharide substrates that typically make up terminal starch digestion products. MGAM and SI are each composed of duplicated catalytic domains, N- and C-terminal, which display overlapping substrate specificities. The N-terminal catalytic domain of human MGAM (ntMGAM) has a preference for short linear alpha-1,4-oligosaccharides, whereas N-terminal SI (ntSI) has a broader specificity for both alpha-1,4- and alpha-1,6-oligosaccharides. Here we present the crystal structure of the human ntSI, in apo form to 3.2 A and in complex with the inhibitor kotalanol to 2.15 A resolution. Structural comparison with the previously solved structure of ntMGAM reveals key active site differences in ntSI, including a narrow hydrophobic +1 subsite, which may account for its additional substrate specificity for alpha-1,6 substrates.


    Organizational Affiliation

    Department of Medical Biophysics, University of Toronto, Ontario Cancer Institute, Toronto, Ontario M56 2M9, Canada.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Sucrase-isomaltase ABCD898Homo sapiensMutation(s): 0 
Gene Names: SI
EC: 3.2.1.10 (PDB Primary Data), 3.2.1.48 (UniProt)
Find proteins for P14410 (Homo sapiens)
Explore P14410 
Go to UniProtKB:  P14410
NIH Common Fund Data Resources
PHAROS:  P14410
Protein Feature View
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  • Reference Sequence
Oligosaccharides

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Entity ID: 2
MoleculeChainsChain Length2D Diagram Glycosylation3D Interactions
2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
E, G
2 N-Glycosylation Oligosaccharides Interaction
Entity ID: 3
MoleculeChainsChain Length2D Diagram Glycosylation3D Interactions
alpha-D-mannopyranose-(1-3)-[alpha-D-mannopyranose-(1-6)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
F, H
5 N-Glycosylation Oligosaccharides Interaction
Small Molecules
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.20 Å
  • R-Value Free: 0.251 
  • R-Value Work: 0.225 
  • R-Value Observed: 0.227 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 76.344α = 90
b = 172.586β = 90
c = 343.874γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PHASERphasing
REFMACrefinement
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

  • Deposited Date: 2010-02-05 
  • Released Date: 2010-03-31 
  • Deposition Author(s): Sim, L., Rose, D.R.

Revision History 

  • Version 1.0: 2010-03-31
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-11-01
    Changes: Advisory, Refinement description
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Database references, Derived calculations, Structure summary