title: Zinc is an essential cofactor for type I isopentenyl diphosphate:dimethylallyl diphosphate isomerase.
abstract: Isopentenyl diphosphate (IPP) isomerase catalyzes the interconversion of IPP and dimethylallyl diphosphate (DMAPP). This is an essential reaction in the mevalonate pathway for biosynthesis of isoprenoid compounds. A crystal structure of Escherichia coli type I IPP isomerase shows a his3glu2 octahedral metal binding site (Durbecq, V. et al. EMBO, 2001, 20, 1530-1537). A metal ion analysis of recombinant E. coli type I IPP isomerase purified from metal-free buffer or buffer containing 10 muM ZnCl2 and 10 muM MnCl2 indicated that the protein contained one atom of Zn2+ per molecule. The metal content and the activity of the enzyme did not change when dialyzed for 6 h against metal-free buffer but rapidly decreased upon dialysis against buffer containing o-phenanthroline. Structural and catalytic roles for Zn2+ are discussed.
authors.affiliation: Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112, USA.
authors.forename: Christina N
authors.initials: CN
authors.lastname: Carrigan
authors.forename: C Dale
authors.initials: CD
authors.lastname: Poulter
mesh_terms: D001665:Binding Sites; D019748:Carbon-Carbon Double Bond Isomerases / Q000737:chemistry* / Q000378:metabolism*; D018360:Crystallography, X-Ray; D004789:Enzyme Activation; D004926:Escherichia coli / Q000201:enzymology; D045782:Hemiterpenes; D007700:Kinetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity; D015032:Zinc / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D045782:Hemiterpenes; D011994:Recombinant Proteins; D019748:Carbon-Carbon Double Bond Isomerases; C021453:isopentenyldiphosphate delta-isomerase; D015032:Zinc