4PVR

Crystal structure of partially-cleaved human l-asparaginase protein in complex with l-aspartate


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.191 
  • R-Value Work: 0.159 
  • R-Value Observed: 0.161 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Structures of apo and product-bound human L-asparaginase: insights into the mechanism of autoproteolysis and substrate hydrolysis.

Nomme, J.Su, Y.Konrad, M.Lavie, A.

(2012) Biochemistry 51: 6816-6826

  • DOI: https://doi.org/10.1021/bi300870g
  • Primary Citation of Related Structures:  
    4PVP, 4PVQ, 4PVR, 4PVS

  • PubMed Abstract: 

    Asparaginases catalyze the hydrolysis of the amino acid asparagine to aspartate and ammonia. Bacterial asparaginases are used in cancer chemotherapy to deplete asparagine from the blood, because several hematological malignancies depend on extracellular asparagine for growth. To avoid the immune response against the bacterial enzymes, it would be beneficial to replace them with human asparaginases. However, unlike the bacterial asparaginases, the human enzymes have a millimolar K(m) value for asparagine, making them inefficient in depleting the amino acid from blood. To facilitate the development of human variants suitable for therapeutic use, we determined the structure of human l-asparaginase (hASNase3). This asparaginase is an N-terminal nucleophile (Ntn) family member that requires autocleavage between Gly167 and Thr168 to become catalytically competent. For most Ntn hydrolases, this autoproteolytic activation occurs efficiently. In contrast, hASNas3 is relatively stable in its uncleaved state, and this allowed us to observe the structure of the enzyme prior to cleavage. To determine the structure of the cleaved state, we exploited our discovery that the free amino acid glycine promotes complete cleavage of hASNase3. Both enzyme states were elucidated in the absence and presence of the product aspartate. Together, these structures provide insight into the conformational changes required for cleavage and the precise enzyme-substrate interactions. The new understanding of hASNase3 will serve to guide the design of variants that possess a decreased K(m) value for asparagine, making the human enzyme a suitable replacement for the bacterial asparaginases in cancer therapy.


  • Organizational Affiliation

    Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Isoaspartyl peptidase/L-asparaginase
A, B
310Homo sapiensMutation(s): 0 
Gene Names: ALPASRGL1CRASH
EC: 3.4.19.5 (PDB Primary Data), 3.5.1.1 (PDB Primary Data)
UniProt & NIH Common Fund Data Resources
Find proteins for Q7L266 (Homo sapiens)
Explore Q7L266 
Go to UniProtKB:  Q7L266
PHAROS:  Q7L266
GTEx:  ENSG00000162174 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ7L266
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.191 
  • R-Value Work: 0.159 
  • R-Value Observed: 0.161 
  • Space Group: P 65
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 59.5α = 90
b = 59.5β = 90
c = 299.5γ = 120
Software Package:
Software NamePurpose
CrystalCleardata collection
MOLREPphasing
REFMACrefinement
XDSdata reduction
XDSdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-03-26
    Type: Initial release
  • Version 1.1: 2023-09-20
    Changes: Data collection, Database references, Derived calculations, Refinement description