2DGN

Mouse Muscle Adenylosuccinate Synthetase partially ligated complex with GTP, 2'-deoxy-IMP


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.198 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Cavitation as a mechanism of substrate discrimination by adenylosuccinate synthetases.

Iancu, C.V.Zhou, Y.Borza, T.Fromm, H.J.Honzatko, R.B.

(2006) Biochemistry 45: 11703-11711

  • DOI: 10.1021/bi0607498
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Adenylosuccinate synthetase catalyzes the first committed step in the de novo biosynthesis of AMP, coupling L-aspartate and IMP to form adenylosuccinate. Km values of IMP and 2'-deoxy-IMP are nearly identical with each substrate supporting comparable ...

    Adenylosuccinate synthetase catalyzes the first committed step in the de novo biosynthesis of AMP, coupling L-aspartate and IMP to form adenylosuccinate. Km values of IMP and 2'-deoxy-IMP are nearly identical with each substrate supporting comparable maximal velocities. Nonetheless, the Km value for L-aspartate and the Ki value for hadacidin (a competitive inhibitor with respect to L-aspartate) are 29-57-fold lower in the presence of IMP than in the presence of 2'-deoxy-IMP. Crystal structures of the synthetase ligated with hadacidin, GDP, and either 6-phosphoryl-IMP or 2'-deoxy-6-phosphoryl-IMP are identical except for the presence of a cavity normally occupied by the 2'-hydroxyl group of IMP. In the presence of 6-phosphoryl-IMP and GDP (hadacidin absent), the L-aspartate pocket can retain its fully ligated conformation, forming hydrogen bonds between the 2'-hydroxyl group of IMP and sequence-invariant residues. In the presence of 2'-deoxy-6-phosphoryl-IMP and GDP, however, the L-aspartate pocket is poorly ordered. The absence of the 2'-hydroxyl group of the deoxyribonucleotide may destabilize binding of the ligand to the L-aspartate pocket by disrupting hydrogen bonds that maintain a favorable protein conformation and by the introduction of a cavity into the fully ligated active site. At an approximate energy cost of 2.2 kcal/mol, the unfavorable thermodynamics of cavity formation may be the major factor in destabilizing ligands at the L-aspartate pocket.


    Organizational Affiliation

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




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Adenylosuccinate synthetase isozyme 1
A
457Mus musculusMutation(s): 0 
Gene Names: Adssl1 (Adss1)
EC: 6.3.4.4
Find proteins for P28650 (Mus musculus)
Go to UniProtKB:  P28650
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GDP
Query on GDP

Download SDF File 
Download CCD File 
A
GUANOSINE-5'-DIPHOSPHATE
C10 H15 N5 O11 P2
QGWNDRXFNXRZMB-UUOKFMHZSA-N
 Ligand Interaction
DOI
Query on DOI

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Download CCD File 
A
9-(2-DEOXY-5-O-PHOSPHONO-BETA-D-ERYTHRO-PENTOFURANOSYL)-6-(PHOSPHONOOXY)-9H-PURINE
2'-DEOXY-IMP
C10 H14 N4 O10 P2
GEECATYOCBMMIR-RRKCRQDMSA-N
 Ligand Interaction
MG
Query on MG

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Download CCD File 
A
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.198 
  • Space Group: P 43 21 2
Unit Cell:
Length (Å)Angle (°)
a = 70.112α = 90.00
b = 70.112β = 90.00
c = 199.033γ = 90.00
Software Package:
Software NamePurpose
CrystalCleardata reduction
AMoREphasing
CrystalCleardata collection
CNSrefinement
CCP4data scaling
TRUNCATEdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-09-15
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Version format compliance