1AJR

REFINEMENT AND COMPARISON OF THE CRYSTAL STRUCTURES OF PIG CYTOSOLIC ASPARTATE AMINOTRANSFERASE AND ITS COMPLEX WITH 2-METHYLASPARTATE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.74 Å
  • R-Value Work: 0.170 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Refinement and comparisons of the crystal structures of pig cytosolic aspartate aminotransferase and its complex with 2-methylaspartate.

Rhee, S.Silva, M.M.Hyde, C.C.Rogers, P.H.Metzler, C.M.Metzler, D.E.Arnone, A.

(1997) J.Biol.Chem. 272: 17293-17302

  • Primary Citation of Related Structures:  1AJS

  • PubMed Abstract: 
  • Two high resolution crystal structures of cytosolic aspartate aminotransferase from pig heart provide additional insights into the stereochemical mechanism for ligand-induced conformational changes in this enzyme. Structures of the homodimeric native ...

    Two high resolution crystal structures of cytosolic aspartate aminotransferase from pig heart provide additional insights into the stereochemical mechanism for ligand-induced conformational changes in this enzyme. Structures of the homodimeric native structure and its complex with the substrate analog 2-methylaspartate have been refined, respectively, with 1.74-A x-ray diffraction data to an R value of 0.170, and with 1.6-A data to an R value of 0.173. In the presence of 2-methylaspartate, one of the subunits (subunit 1) shows a ligand-induced conformational change that involves a large movement of the small domain (residues 12-49 and 327-412) to produce a "closed" conformation. No such transition is observed in the other subunit (subunit 2), because crystal lattice contacts lock it in an "open" conformation like that adopted by subunit 1 in the absence of substrate. By comparing the open and closed forms of cAspAT, we propose a stereochemical mechanism for the open-to-closed transition that involves the electrostatic neutralization of two active site arginine residues by the negative charges of the incoming substrate, a large change in the backbone (phi,psi) conformational angles of two key glycine residues, and the entropy-driven burial of a stretch of hydrophobic residues on the N-terminal helix. The calculated free energy for the burial of this "hydrophobic plug" appears to be sufficient to serve as the driving force for domain closure.


    Related Citations: 
    • Pig Cytosolic Aspartate Aminotransferase
      Arnone, A.,Rogers, P.H.,Hyde, C.C.,Briley, P.D.,Metzler, C.M.,Metzler, D.E.
      (1985) Transaminases --: 138


    Organizational Affiliation

    Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
ASPARTATE AMINOTRANSFERASE
A, B
412Sus scrofaGene Names: GOT1
EC: 2.6.1.1, 2.6.1.3
Find proteins for P00503 (Sus scrofa)
Go to Gene View: GOT1
Go to UniProtKB:  P00503
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
LLP
Query on LLP
A, B
L-PEPTIDE LINKINGC14 H22 N3 O7 PLYS
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.74 Å
  • R-Value Work: 0.170 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 125.000α = 90.00
b = 130.800β = 90.00
c = 55.800γ = 90.00
Software Package:
Software NamePurpose
PROLSQrefinement
UCSDdata reduction
SEEmodel building
FROMdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1997-08-20
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance