6acn
From Proteopedia
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
6ACN is a Single protein structure of sequence from Sus scrofa. 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 Page seeded by OCA on Sun May 4 22:38:58 2008
