2H2U

Crystal structure of the E130Y mutant of human soluble calcium-activated nucleotidase (SCAN) with calcium ion


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.285 
  • R-Value Work: 0.216 
  • R-Value Observed: 0.220 

Starting Model: experimental
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This is version 1.5 of the entry. See complete history


Literature

Calcium-dependent dimerization of human soluble calcium activated nucleotidase: characterization of the dimer interface.

Yang, M.Horii, K.Herr, A.B.Kirley, T.L.

(2006) J Biol Chem 281: 28307-28317

  • DOI: https://doi.org/10.1074/jbc.M604413200
  • Primary Citation of Related Structures:  
    2H2N, 2H2U

  • PubMed Abstract: 

    Mammals express a protein homologous to soluble nucleotidases used by blood-sucking insects to inhibit host blood clotting. These vertebrate nucleotidases may play a role in protein glycosylation. The activity of this enzyme family is strictly dependent on calcium, which induces a conformational change in the secreted, soluble human nucleotidase. The crystal structure of this human enzyme was recently solved; however, the mechanism of calcium activation and the basis for the calcium-induced changes remain unclear. In this study, using analytical ultracentrifugation and chemical cross-linking, we show that calcium or strontium induce noncovalent dimerization of the soluble human enzyme. The location and nature of the dimer interface was elucidated using a combination of site-directed mutagenesis and chemical cross-linking, coupled with crystallographic analyses. Replacement of Ile(170), Ser(172), and Ser(226) with cysteine residues resulted in calcium-dependent, sulfhydryl-specific intermolecular cross-linking, which was not observed after cysteine introduction at other surface locations. Analysis of a super-active mutant, E130Y, revealed that this mutant dimerized more readily than the wild-type enzyme. The crystal structure of the E130Y mutant revealed that the mutated residue is found in the dimer interface. In addition, expression of the full-length nucleotidase revealed that this membrane-bound form can also dimerize and that these dimers are stabilized by spontaneous oxidative cross-linking of Cys(30), located between the single transmembrane helix and the start of the soluble sequence. Thus, calcium-mediated dimerization may also represent a mechanism for regulation of the activity of this nucleotidase in the physiological setting of the endoplasmic reticulum or Golgi.


  • Organizational Affiliation

    Department of Pharmacology and Cell Biophysics, College of Medicine, University of Cincinnati College of Medicine, Ohio 45267-0575, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Soluble calcium-activated nucleotidase 1
A, B
339Homo sapiensMutation(s): 1 
Gene Names: CANT1SHAPY
EC: 3.6.1.6
UniProt & NIH Common Fund Data Resources
Find proteins for Q8WVQ1 (Homo sapiens)
Explore Q8WVQ1 
Go to UniProtKB:  Q8WVQ1
PHAROS:  Q8WVQ1
GTEx:  ENSG00000171302 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8WVQ1
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.285 
  • R-Value Work: 0.216 
  • R-Value Observed: 0.220 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 42.891α = 100.94
b = 52.412β = 106.51
c = 77.806γ = 99.32
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PHASERphasing
REFMACrefinement
PDB_EXTRACTdata extraction
MAR345data collection

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-07-18
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-18
    Changes: Refinement description
  • Version 1.4: 2021-10-20
    Changes: Database references, Derived calculations
  • Version 1.5: 2023-08-30
    Changes: Data collection, Refinement description