4O47

Crystal structure of uncleaved guinea pig L-asparaginase type III


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.194 

Starting Model: experimental
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This is version 1.2 of the entry. See complete history


Literature

Structural and Kinetic Characterization of Guinea Pig l-Asparaginase Type III.

Schalk, A.M.Lavie, A.

(2014) Biochemistry 53: 2318-2328

  • DOI: https://doi.org/10.1021/bi401692v
  • Primary Citation of Related Structures:  
    4O47, 4O48

  • PubMed Abstract: 

    We investigated whether an uncharacterized protein from guinea pig could be the enzyme behind Kidd's serendipitous discovery, made over 60 years ago, that guinea pig serum has cell killing ability. It has been long known that an enzyme with l-asparaginase activity is responsible for cell killing, although astonishingly, its identity remains unclear. Bacterial asparaginases with similar cell killing properties have since become a mainstay therapy of certain cancers such as acute lymphoblastic leukemia. By hydrolyzing asparagine to aspartate and ammonia, these drugs deplete the asparagine present in the blood, killing cancer cells that rely on extracellular asparagine uptake for survival. However, bacterial asparaginases can elicit an adverse immune response. We propose that replacement of bacterial enzymes with the guinea pig asparaginase responsible for serum activity, by its virtue of being more closely related to human enzymes, will be less immunogenic. To this goal, we investigated whether an uncharacterized protein from guinea pig with putative asparaginase activity, which we call gpASNase3, could be that enzyme. We examined its self-activation process (gpASNase3 requires autocleavage to become active), kinetically characterized it for asparaginase and β-aspartyl dipeptidase activity, and elucidated its crystal structure in both the uncleaved and cleaved states. This work reveals that gpASNase3 is not the enzyme responsible for the antitumor effects of guinea pig serum. It exhibits a low affinity for asparagine as measured by a high Michaelis constant, KM, in the millimolar range, in contrast to the low KM (micromolar range) required for asparaginase to be effective as an anticancer agent.


  • Organizational Affiliation

    Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago , 900 S. Ashland, Chicago , Illinois 60607, United States.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Uncharacterized protein
A, B
332Cavia porcellusMutation(s): 0 
Gene Names: LOC100713636
EC: 3.5.1.1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.194 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 114.872α = 90
b = 114.872β = 90
c = 138.971γ = 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: 2014-04-09
    Type: Initial release
  • Version 1.1: 2014-05-07
    Changes: Database references
  • Version 1.2: 2023-09-20
    Changes: Data collection, Database references, Derived calculations, Refinement description