title: Characterization of the cupin-type phosphoglucose isomerase from the hyperthermophilic archaeon Thermococcus litoralis.
abstract: The gene encoding phosphoglucose isomerase was cloned from Thermococcus litoralis, and functionally expressed in Escherichia coli. The purified enzyme, a homodimer of 21.5 kDa subunits, was biochemically characterized. The inhibition constants for four competitive inhibitors were determined. The enzyme contained 1.25 mol Fe and 0.24 mol Zn per dimer. The activity was enhanced by the addition of Fe(2+), but inhibited by Zn(2+) and EDTA. Enzymes with mutations in conserved histidine and glutamate residues in their cupin motifs contained no metals, and showed large decreases in k(cat). The circular dichroism spectra of the mutant enzymes and the wild type enzyme were essentially the same but with slight differences.
authors.affiliation: Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Jong-Jin
authors.initials: JJ
authors.lastname: Jeong
authors.forename: Shinya
authors.initials: S
authors.lastname: Fushinobu
authors.forename: Sohei
authors.initials: S
authors.lastname: Ito
authors.forename: Beong-Sam
authors.initials: BS
authors.lastname: Jeon
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Shoun
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Wakagi
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics; D001665:Binding Sites / Q000235:genetics / Q000502:physiology; D001667:Binding, Competitive / Q000187:drug effects; D002384:Catalysis; D002614:Chelating Agents / Q000494:pharmacology; D002942:Circular Dichroism; D003001:Cloning, Molecular; D019281:Dimerization; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005956:Glucose-6-Phosphate Isomerase / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics*; D007501:Iron / Q000737:chemistry / Q000494:pharmacology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016297:Mutagenesis, Site-Directed; D017386:Sequence Homology, Amino Acid; D013053:Spectrophotometry; D013329:Structure-Activity Relationship; D013696:Temperature; D019712:Thermococcus / Q000201:enzymology*; D015032:Zinc / Q000737:chemistry / Q000494:pharmacology
chemical_list: D019843:Archaeal Proteins; D002614:Chelating Agents; D004791:Enzyme Inhibitors; D007501:Iron; D005956:Glucose-6-Phosphate Isomerase; D015032:Zinc