Details

Autor(en) / Beteiligte

• Robbins, A. H.
• Stout, C. D.

Titel

Structure of Activated Aconitase: Formation of the [4Fe-4S] Cluster in the Crystal

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 1989-05, Vol.86 (10), p.3639-3643

Ort / Verlag

Washington, DC: National Academy of Sciences of the United States of America

Erscheinungsjahr

1989

Quelle

MEDLINE

Beschreibungen/Notizen

• 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- angstrom resolution to a crystallographic residual of 18.2%. Comparison of this structure to the recently determined 2.1- angstrom 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 angstrom; the three common cysteinyl Sγligand atoms agree within 0.25 angstrom. 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.