4GNC

human SMP30/GNL-1,5-AG complex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.197 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history


Literature

Structural basis of the gamma-lactone-ring formation in ascorbic acid biosynthesis by the senescence marker protein-30/gluconolactonase

Aizawa, S.Senda, M.Harada, A.Maruyama, N.Ishida, T.Aigaki, T.Ishigami, A.Senda, T.

(2013) PLoS One 8: e53706-e53706

  • DOI: https://doi.org/10.1371/journal.pone.0053706
  • Primary Citation of Related Structures:  
    4GN7, 4GN8, 4GN9, 4GNA, 4GNB, 4GNC

  • PubMed Abstract: 

    The senescence marker protein-30 (SMP30), which is also called regucalcin, exhibits gluconolactonase (GNL) activity. Biochemical and biological analyses revealed that SMP30/GNL catalyzes formation of the γ-lactone-ring of L-gulonate in the ascorbic acid biosynthesis pathway. The molecular basis of the γ-lactone formation, however, remains elusive due to the lack of structural information on SMP30/GNL in complex with its substrate. Here, we report the crystal structures of mouse SMP30/GNL and its complex with xylitol, a substrate analogue, and those with 1,5-anhydro-D-glucitol and D-glucose, product analogues. Comparison of the crystal structure of mouse SMP30/GNL with other related enzymes has revealed unique characteristics of mouse SMP30/GNL. First, the substrate-binding pocket of mouse SMP30/GNL is designed to specifically recognize monosaccharide molecules. The divalent metal ion in the active site and polar residues lining the substrate-binding cavity interact with hydroxyl groups of substrate/product analogues. Second, in mouse SMP30/GNL, a lid loop covering the substrate-binding cavity seems to hamper the binding of L-gulonate in an extended (or all-trans) conformation; L-gulonate seems to bind to the active site in a folded conformation. In contrast, the substrate-binding cavities of the other related enzymes are open to the solvent and do not have a cover. This structural feature of mouse SMP30/GNL seems to facilitate the γ-lactone-ring formation.


  • Organizational Affiliation

    Cellular Genetics, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji, Tokyo, Japan.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Regucalcin
A, B
299Homo sapiensMutation(s): 0 
Gene Names: SMP30
EC: 3.1.1.17
UniProt & NIH Common Fund Data Resources
Find proteins for Q15493 (Homo sapiens)
Explore Q15493 
Go to UniProtKB:  Q15493
PHAROS:  Q15493
GTEx:  ENSG00000130988 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ15493
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.197 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 64.407α = 90
b = 50.202β = 99.65
c = 86.569γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
MOLREPphasing
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-04-10
    Type: Initial release
  • Version 1.1: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Data collection, Derived calculations, Structure summary
  • Version 1.2: 2023-11-08
    Changes: Advisory, Data collection, Database references, Refinement description, Structure summary