1AAW

THE STRUCTURAL BASIS FOR THE ALTERED SUBSTRATE SPECIFICITY OF THE R292D ACTIVE SITE MUTANT OF ASPARTATE AMINOTRANSFERASE FROM E. COLI


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Observed: 0.208 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

The structural basis for the altered substrate specificity of the R292D active site mutant of aspartate aminotransferase from E. coli.

Almo, S.C.Smith, D.L.Danishefsky, A.T.Ringe, D.

(1994) Protein Eng 7: 405-412

  • DOI: https://doi.org/10.1093/protein/7.3.405
  • Primary Citation of Related Structures:  
    1AAM, 1AAW

  • PubMed Abstract: 

    Two refined crystal structures of aspartate aminotransferase from E. coli are reported. The wild type enzyme is in the pyridoxal phosphate (PLP) form and its structure has been determined to 2.4 A resolution, refined to an R-factor of 23.2%. The structure of the Arg292Asp mutant has been determined at 2.8 A resolution, refined to an R-factor of 20.3%. The wild type and mutant crystals are isomorphous and the two structures are very similar, with only minor changes in positions of important active site residues. As residue Arg292 is primarily responsible for the substrate charge specificity in the wild type enzyme, the mutant containing a charge reversal at this position might be expected to catalyze transamination of arginine as efficiently as the wild type enzyme effects transamination of aspartate [Cronin, C.N. and Kirsch, J.F. (1988) Biochemistry, 27, 4572-4579]. This mutant does in fact prefer arginine over aspartate as a substrate, however, the rate of catalysis is much slower than that of the wild type enzyme with its physiological substrate, aspartate. A comparison of these two structures indicates that the poorer catalytic efficiency of R292D, when presented with arginine, is not due to a gross conformational difference, but is rather a consequence of both small side chain and main chain reorientations and the pre-existing active site polar environment, which greatly favors the wild type ion pair interaction.


  • Organizational Affiliation

    Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ASPARTATE AMINOTRANSFERASE396Escherichia coliMutation(s): 0 
EC: 2.6.1.1
UniProt
Find proteins for P00509 (Escherichia coli (strain K12))
Explore P00509 
Go to UniProtKB:  P00509
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00509
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
PLP
Query on PLP

Download Ideal Coordinates CCD File 
B [auth A]PYRIDOXAL-5'-PHOSPHATE
C8 H10 N O6 P
NGVDGCNFYWLIFO-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Observed: 0.208 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 156.8α = 90
b = 86.9β = 90
c = 80γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
PROLSQrefinement
X-PLORrefinement
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1993-10-31
    Type: Initial release
  • Version 1.1: 2008-03-03
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.3: 2024-06-05
    Changes: Data collection, Database references, Derived calculations, Other