title: Tetartohedral twinning in IDI-2 from Thermus thermophilus: crystallization under anaerobic conditions.
abstract: Type-2 isopentenyl diphosphate isomerase (IDI-2) is a key flavoprotein involved in the biosynthesis of isoprenoids. Since fully reduced flavin mononucleotide (FMNH2) is needed for activity, it was decided to crystallize the enzyme under anaerobic conditions in order to understand how this reduced cofactor binds within the active site and interacts with the substrate isopentenyl diphosphate (IPP). In this study, the protein was expressed and purified under aerobic conditions and then reduced and crystallized under anaerobic conditions. Crystals grown by the sitting-drop vapour-diffusion method and then soaked with IPP diffracted to 2.1 Å resolution and belonged to the hexagonal space group P6322, with unit-cell parameters a = b = 133.3, c = 172.9 Å.
authors.affiliation: Department of Chemistry, University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium.
authors.forename: Jerome
authors.initials: J
authors.lastname: de Ruyck
authors.affiliation: Department of Biochemistry, University of Utah School of Medicine, 15 North Medical Drive, Salt Lake City, UT 84112, USA.
authors.forename: Heidi L
authors.initials: HL
authors.lastname: Schubert
authors.affiliation: Department of Chemistry, University of Utah, 315 South 1400 East, Rm 2020, Salt Lake City, UT 84112, United States.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Janczak
authors.affiliation: Department of Chemistry, University of Utah, 315 South 1400 East, Rm 2020, Salt Lake City, UT 84112, United States.
authors.forename: C Dale
authors.initials: CD
authors.lastname: Poulter
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D019748:Carbon-Carbon Double Bond Isomerases / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D045782:Hemiterpenes; D010100:Oxygen / Q000737:chemistry; D016963:Thermus thermophilus / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D045782:Hemiterpenes; D019748:Carbon-Carbon Double Bond Isomerases; C021453:isopentenyldiphosphate delta-isomerase; D010100:Oxygen
keywords: IDI-2; anaerobic; flavoprotein; isopentenyl diphosphate isomerase; isoprenoid; twinning