title: Structure of isochorismate synthase in complex with magnesium.
abstract: The electron carrier menaquinone is one of many important bacterial metabolites that are derived from the key intermediate chorismic acid. MenF, the first enzyme in the menaquinone pathway, catalyzes the isomerization of chorismate to isochorismate. Here, an improved structure of MenF in a new crystal form is presented. The structure, solved at 2.0 angstroms resolution in complex with magnesium, reveals a well defined closed active site. Existing evidence suggests that the mechanism of the reaction catalyzed by MenF involves nucleophilic attack of a water molecule on the chorismate ring. The structure reveals a well defined water molecule located in an appropriate position for activation by Lys190 and attack on the substrate.
authors.affiliation: Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, USA. parsonsj@umbi.umd.edu
authors.forename: James F
authors.initials: JF
authors.lastname: Parsons
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Shi
authors.forename: Jane E
authors.initials: JE
authors.lastname: Ladner
mesh_terms: D018360:Crystallography, X-Ray / Q000379:methods; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019751:Intramolecular Transferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008274:Magnesium / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D015394:Molecular Structure; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
chemical_list: D029968:Escherichia coli Proteins; D019751:Intramolecular Transferases; C058486:isochorismate synthase; D008274:Magnesium