title: Structure of free fumarase C from Escherichia coli.
abstract: Previous crystal structures of fumarase C from Escherichia coli have noted two occupied dicarboxylate-binding sites termed the active site and the B site. Here, the first known fumarase C structure is reported in which both sites are unoccupied by bound ligand. This so-called ;free' crystal form shows conservation of the active-site water in a similar orientation to that reported in other fumarase C crystal structures. More importantly, a shift of His129 has been observed at the B site. This new crystallographic information suggests the use of water as a permanent member of the active site and the use of an imidazole-imidazolium conversion to control access at the allosteric B site.
authors.affiliation: Department of Chemistry, University of Wisconsin-La Crosse, 1725 State Street, 4020 Cowley Hall, La Crosse, Wisconsin 54601, USA. weaver.todd@uwlax.edu
authors.forename: Todd
authors.initials: T
authors.lastname: Weaver
mesh_terms: D000495:Allosteric Site; D001426:Bacterial Proteins / Q000737:chemistry; D001665:Binding Sites; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000201:enzymology*; D005649:Fumarate Hydratase / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry; D007477:Ions; D008024:Ligands; D046911:Macromolecular Substances / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D011485:Protein Binding; D011487:Protein Conformation; D055672:Static Electricity
chemical_list: D001426:Bacterial Proteins; D007093:Imidazoles; D007477:Ions; D008024:Ligands; D046911:Macromolecular Substances; C029899:imidazole; C095842:fumarase C; D005649:Fumarate Hydratase