The structure of aconitase.
The crystal structure of the 80,000 Da Fe-S enzyme aconitase has been solved and refined at 2.1 A resolution. The protein contains four domains; the first three from the N-terminus are closely associated around the [3Fe-4S] cluster with all three cysteine ligands to the cluster being provided by the third domain. Association of the larger C-terminal domain with the first three domains creates an extensive cleft leading to the Fe-S cluster. Residues from all four domains contribute to the active site region, which is defined by the Fe-S cluster and a bound SO4(2-) ion. This region of the structure contains 4 Arg, 3 His, 3 Ser, 2 Asp, 1 Glu, 3 Asn, and 1 Gln residues, as well as several bound water molecules. Three of these side chains reside on a three-turn 3(10) helix in the first domain. The SO4(2-) ion is bound 9.3 A from the center of the [3Fe-4S] cluster by the side chains of 2 Arg and 1 Gln residues. Each of 3 His side chains in the putative active site is paired with Asp or Glu side chains.
Robbins
A H
AH
Research Institute of Scripps Clinic, La Jolla, California 92037.
Stout
C D
CD
D000154:Aconitate Hydratase; D000818:Animals; D007506:Iron-Sulfur Proteins; D046911:Macromolecular Substances; D008958:Models, Molecular; D008970:Molecular Weight; D009206:Myocardium / Q000201:enzymology; D011487:Protein Conformation; D013552:Swine; D014961:X-Ray Diffraction
D007506:Iron-Sulfur Proteins; D046911:Macromolecular Substances; D000154:Aconitate Hydratase