6V23

Ligand-free L-aspraginase II from E. coli (EcAII)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.185 

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This is version 1.3 of the entry. See complete history


Literature

Mechanism of Catalysis by l-Asparaginase.

Lubkowski, J.Vanegas, J.Chan, W.K.Lorenzi, P.L.Weinstein, J.N.Sukharev, S.Fushman, D.Rempe, S.Anishkin, A.Wlodawer, A.

(2020) Biochemistry 59: 1927-1945

  • DOI: https://doi.org/10.1021/acs.biochem.0c00116
  • Primary Citation of Related Structures:  
    6V23, 6V24, 6V25, 6V26, 6V27, 6V28, 6V29, 6V2A, 6V2B, 6V2C, 6V2G

  • PubMed Abstract: 

    Two bacterial type II l-asparaginases, from Escherichia coli and Dickeya chrysanthemi , have played a critical role for more than 40 years as therapeutic agents against juvenile leukemias and lymphomas. Despite a long history of successful pharmacological applications and the apparent simplicity of the catalytic reaction, controversies still exist regarding major steps of the mechanism. In this report, we provide a detailed description of the reaction catalyzed by E. coli type II l-asparaginase (EcAII). Our model was developed on the basis of new structural and biochemical experiments combined with previously published data. The proposed mechanism is supported by quantum chemistry calculations based on density functional theory. We provide strong evidence that EcAII catalyzes the reaction according to the double-displacement (ping-pong) mechanism, with formation of a covalent intermediate. Several steps of catalysis by EcAII are unique when compared to reactions catalyzed by other known hydrolytic enzymes. Here, the reaction is initiated by a weak nucleophile, threonine, without direct assistance of a general base, although a distant general base is identified. Furthermore, tetrahedral intermediates formed during the catalytic process are stabilized by a never previously described motif. Although the scheme of the catalytic mechanism was developed only on the basis of data obtained from EcAII and its variants, this novel mechanism of enzymatic hydrolysis could potentially apply to most (and possibly all) l-asparaginases.


  • Organizational Affiliation

    Macromolecular Crystallography Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, United States.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
L-asparaginase 2333Escherichia coli K-12Mutation(s): 0 
Gene Names: ansBb2957JW2924
EC: 3.5.1.1
UniProt
Find proteins for P00805 (Escherichia coli (strain K12))
Explore P00805 
Go to UniProtKB:  P00805
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00805
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.185 
  • Space Group: I 2 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 62.028α = 90
b = 71.192β = 90
c = 130.03γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
HKL-2000data scaling
REFMACrefinement
PDB_EXTRACTdata extraction
PHASERphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2020-05-20
    Type: Initial release
  • Version 1.1: 2020-05-27
    Changes: Database references
  • Version 1.2: 2020-06-10
    Changes: Database references
  • Version 1.3: 2023-10-11
    Changes: Data collection, Database references, Refinement description