7ACN

CRYSTAL STRUCTURES OF ACONITASE WITH ISOCITRATE AND NITROISOCITRATE BOUND


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Work: 0.179 
  • R-Value Observed: 0.179 

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This is version 1.3 of the entry. See complete history


Literature

Crystal structures of aconitase with isocitrate and nitroisocitrate bound.

Lauble, H.Kennedy, M.C.Beinert, H.Stout, C.D.

(1992) Biochemistry 31: 2735-2748

  • DOI: 10.1021/bi00125a014
  • Primary Citation of Related Structures:  
    7ACN, 8ACN

  • PubMed Abstract: 
  • The crystal structures of mitochondrial aconitase with isocitrate and nitroisocitrate bound have been solved and refined to R factors of 0.179 and 0.161, respectively, for all observed data in the range 8.0-2.1 A. Porcine heart enzyme was used for de ...

    The crystal structures of mitochondrial aconitase with isocitrate and nitroisocitrate bound have been solved and refined to R factors of 0.179 and 0.161, respectively, for all observed data in the range 8.0-2.1 A. Porcine heart enzyme was used for determining the structure with isocitrate bound. The presence of isocitrate in the crystals was corroborated by Mössbauer spectroscopy. Bovine heart enzyme was used for determining the structure with the reaction intermediate analogue nitroisocitrate bound. The inhibitor binds to the enzyme in a manner virtually identical to that of isocitrate. Both compounds bind to the unique Fe atom of the [4Fe-4S] cluster via a hydroxyl oxygen and one carboxyl oxygen. A H2O molecule is also bound, making Fe six-coordinate. The unique Fe is pulled away approximately 0.2 A from the corner of the cubane compared to the position it would occupy in a symmetrically ligated [4Fe-4S] cluster. At least 23 residues from all four domains of aconitase contribute to the active site. These residues participate in substrate recognition (Arg447, Arg452, Arg580, Arg644, Gln72, Ser166, Ser643), cluster ligation and interaction (Cys358, Cys421, Cys424, Asn258, Asn446), and hydrogen bonds supporting active site side chains (Ala74, Asp568, Ser571, Thr567). Residues implicated in catalysis are Ser642 and three histidine-carboxylate pairs (Asp100-His101, Asp165-His147, Glu262-His167). The base necessary for proton abstraction from C beta of isocitrate appears to be Ser642; the O gamma atom is proximal to the calculated hydrogen position, while the environment of O gamma suggests stabilization of an alkoxide (an oxyanion hole formed by the amide and side chain of Arg644). The histidine-carboxylate pairs appear to be required for proton transfer reactions involving two oxygens bound to Fe, one derived from solvent (bound H2O) and one derived from substrate hydroxyl. Each oxygen is in contact with a histidine, and both are in contact with the side chain of Asp165, which bridges the two sites on the six-coordinate Fe.


    Related Citations: 
    • Structure of Activated Aconitase. Formation of the (4Fe-4S) Cluster in the Crystal
      Robbins, A.H., Stout, C.D.
      (1989) Proc Natl Acad Sci U S A 86: 3639
    • The Structure of Aconitase
      Robbins, A.H., Stout, C.D.
      (1989) Proteins 5: 289
    • Iron-Sulfur Cluster in Aconitase. Crystallographic Evidence for a Three-Iron Center
      Robbins, A.H., Stout, C.D.
      (1985) J Biol Chem 260: 2328

    Organizational Affiliation

    Department of Molecular Biology, Scripps Research Institute, La Jolla, California 92037.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
ACONITASEA754Sus scrofaMutation(s): 0 
Gene Names: ACO2
EC: 4.2.1.3
Find proteins for P16276 (Sus scrofa)
Explore P16276 
Go to UniProtKB:  P16276
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SF4
Query on SF4

Download CCD File 
A
IRON/SULFUR CLUSTER
Fe4 S4
LJBDFODJNLIPKO-VKOJMFJBAC
 Ligand Interaction
ICT
Query on ICT

Download CCD File 
A
ISOCITRIC ACID
C6 H8 O7
ODBLHEXUDAPZAU-ZAFYKAAXSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
PCA
Query on PCA
AL-PEPTIDE LINKINGC5 H7 N O3GLN
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Work: 0.179 
  • R-Value Observed: 0.179 
  • Space Group: B 1 1 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 185.5α = 90
b = 72β = 90
c = 73γ = 77.7
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • 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: Version format compliance
  • Version 1.3: 2017-11-29
    Changes: Derived calculations, Other