5TCD

Human alkaline sphingomyelinase (ENPP7) in complex with phosphocholine


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.173 
  • R-Value Observed: 0.175 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Crystal structure of the human alkaline sphingomyelinase provides insights into substrate recognition.

Gorelik, A.Liu, F.Illes, K.Nagar, B.

(2017) J Biol Chem 292: 7087-7094

  • DOI: 10.1074/jbc.M116.769273
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • Absorption of dietary sphingomyelin (SM) requires its initial degradation into ceramide, a process catalyzed by the intestinal enzyme alkaline sphingomyelinase (alk-SMase, NPP7, ENPP7 ). alk-SMase belongs to the nucleotide pyrophosphatase/pho ...

    Absorption of dietary sphingomyelin (SM) requires its initial degradation into ceramide, a process catalyzed by the intestinal enzyme alkaline sphingomyelinase (alk-SMase, NPP7, ENPP7 ). alk-SMase belongs to the nucleotide pyrophosphatase/phosphodiesterase (NPP) family, the members of which hydrolyze nucleoside phosphates, phospholipids, and other related molecules. NPP7 is the only paralog that can cleave SM, and its activity requires the presence of bile salts, a class of physiological anionic detergents. To elucidate the mechanism of substrate recognition, we determined the crystal structure of human alk-SMase in complex with phosphocholine, a reaction product. Although the overall fold and catalytic center are conserved relative to other NPPs, alk-SMase recognizes the choline moiety of its substrates via an NPP7-specific aromatic box composed of tyrosine residues. Mutational analysis and enzymatic activity assays identified features on the surface of the protein-a cationic patch and a unique hydrophobic loop-that are essential for accessing SM in bile salt micelles. These results shed new light on substrate specificity determinants within the NPP enzyme family.


    Organizational Affiliation

    From the Department of Biochemistry and Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, Quebec H3G 0B1, Canada bhushan.nagar@mcgill.ca.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Ectonucleotide pyrophosphatase/phosphodiesterase family member 7
A
422Homo sapiensMutation(s): 0 
Gene Names: ENPP7UNQ3077/PRO9912
EC: 3.1.4.12
Find proteins for Q6UWV6 (Homo sapiens)
Go to UniProtKB:  Q6UWV6
NIH Common Fund Data Resources
PHAROS  Q6UWV6
Protein Feature View
  • Reference Sequence
Small Molecules
Ligands 7 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAG
Query on NAG

Download CCD File 
A
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
PC
Query on PC

Download CCD File 
A
PHOSPHOCHOLINE
C5 H15 N O4 P
YHHSONZFOIEMCP-UHFFFAOYSA-O
 Ligand Interaction
BMA
Query on BMA

Download CCD File 
A
BETA-D-MANNOSE
C6 H12 O6
WQZGKKKJIJFFOK-RWOPYEJCSA-N
 Ligand Interaction
FUC
Query on FUC

Download CCD File 
A
ALPHA-L-FUCOSE
C6 H12 O5
SHZGCJCMOBCMKK-SXUWKVJYSA-N
 Ligand Interaction
IOD
Query on IOD

Download CCD File 
A
IODIDE ION
I
XMBWDFGMSWQBCA-UHFFFAOYSA-M
 Ligand Interaction
ZN
Query on ZN

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A
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
NA
Query on NA

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A
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.173 
  • R-Value Observed: 0.175 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 104.223α = 90
b = 104.223β = 90
c = 113.893γ = 120
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling
PHENIXphasing

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Canadian Institutes of Health Research (CIHR)CanadaMOP-133535

Revision History 

  • Version 1.0: 2017-03-22
    Type: Initial release
  • Version 1.1: 2017-05-10
    Changes: Database references
  • Version 1.2: 2020-01-08
    Changes: Author supporting evidence, Data collection