IMP Complex of E. Coli Adenylosuccinate Synthetase

Experimental Data Snapshot

  • Resolution: 2.60 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.196 

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This is version 1.5 of the entry. See complete history


IMP Alone Organizes the Active Site of Adenylosuccinate Synthetase from Escherichia coli.

Hou, Z.Wang, W.Fromm, H.J.Honzatko, R.B.

(2002) J Biol Chem 277: 5970-5976

  • DOI: https://doi.org/10.1074/jbc.M109561200
  • Primary Citation of Related Structures:  
    1KJX, 1KKB, 1KKF

  • PubMed Abstract: 

    A complete set of substrate/substrate analogs of adenylosuccinate synthetase from Escherichia coli induces dimer formation and a transition from a disordered to an ordered active site. The most striking of the ligand-induced effects is the movement of loop 40-53 by up to 9 A. Crystal structures of the partially ligated synthetase, which either combine IMP and hadacidin or IMP, hadacidin, and Mg(2+)-pyrophosphate, have ordered active sites, comparable with the fully ligated enzyme. More significantly, a crystal structure of the synthetase with IMP alone exhibits a largely ordered active site, which includes the 9 A movement of loop 40-53 but does not include conformational adjustments to backbone carbonyl 40 (Mg(2+) interaction element) and loop 298-304 (L-aspartate binding element). Interactions involving the 5'-phosphoryl group of IMP evidently trigger the formation of salt links some 30 A away. The above provides a structural basis for ligand binding synergism, effects on k(cat) due to mutations far from the site of catalysis, and the complete loss of substrate efficacy due to minor alterations of the 5'-phosphoryl group of IMP.

  • Organizational Affiliation

    Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Adenylosuccinate Synthetase432Escherichia coli K-12Mutation(s): 0 
Find proteins for P0A7D4 (Escherichia coli (strain K12))
Explore P0A7D4 
Go to UniProtKB:  P0A7D4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0A7D4
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on IMP

Download Ideal Coordinates CCD File 
C10 H13 N4 O8 P
Experimental Data & Validation

Experimental Data

  • Resolution: 2.60 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.196 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 80.6α = 90
b = 80.6β = 90
c = 158.65γ = 120
Software Package:
Software NamePurpose
X-PLORmodel building
X-GENdata reduction
X-GENdata scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2002-03-20
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.3: 2016-06-01
    Changes: Source and taxonomy
  • Version 1.4: 2017-10-11
    Changes: Refinement description
  • Version 1.5: 2024-02-14
    Changes: Data collection, Database references, Derived calculations