3LPO

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


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.2 Å
  • R-Value Free: 0.251 
  • R-Value Work: 0.225 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

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:  

  • 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 d ...

    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: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Sucrase-isomaltase
A, B, C, D
898Homo sapiensMutation(s): 0 
Gene Names: SI
Find proteins for P14410 (Homo sapiens)
Go to Gene View: SI
Go to UniProtKB:  P14410
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MAN
Query on MAN

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

Download SDF File 
Download CCD File 
A, C
BETA-D-MANNOSE
C6 H12 O6
WQZGKKKJIJFFOK-RWOPYEJCSA-N
 Ligand Interaction
NAG
Query on NAG

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

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.2 Å
  • R-Value Free: 0.251 
  • R-Value Work: 0.225 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 76.344α = 90.00
b = 172.586β = 90.00
c = 343.874γ = 90.00
Software Package:
Software NamePurpose
PHASERphasing
DENZOdata reduction
REFMACrefinement
PDB_EXTRACTdata extraction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



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
    Type: Version format compliance
  • Version 1.2: 2017-11-01
    Type: Advisory, Refinement description