5acn | pdb_00005acn
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STRUCTURE OF ACTIVATED ACONITASE. FORMATION OF THE (4FE-4S) CLUSTER IN THE CRYSTAL
Overview
The structure of activated pig heart aconitase [citrate(isocitrate) hydro-lyase, EC 4.2.1.3] containing a [4Fe-4S] cluster has been refined at 2.5-A resolution to a crystallographic residual of 18.2%. Comparison of this structure to the recently determined 2.1-A resolution structure of the inactive enzyme containing a [3Fe-4S] cluster, by difference Fourier analysis, shows that upon activation iron is inserted into the structure isomorphously. The common atoms of the [3Fe-4S] and [4Fe-4S] cores agree within 0.1 A; the three common cysteinyl S gamma ligand atoms agree within 0.25 A. The fourth ligand of the Fe inserted into the [3Fe-4S] cluster is a water or hydroxyl from solvent, consistent with the absence of a free cysteine ligand in the enzyme active site cleft and the isomorphism of the two structures. A water molecule occupies a similar site in the crystal structure of the inactive enzyme.
About this Structure
5ACN is a Single protein structure of sequence from Sus scrofa with SO4, F3S and TRC as ligands. Active as Aconitate hydratase, with EC number 4.2.1.3 Full crystallographic information is available from OCA.
Reference
Structure of activated aconitase: formation of the [4Fe-4S] cluster in the crystal., Robbins AH, Stout CD, Proc Natl Acad Sci U S A. 1989 May;86(10):3639-43. PMID:2726740
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