title: Thermostable chimeric PQQ glucose dehydrogenase.
abstract: The thermal stability of PQQ glucose dehydrogenases (PQQGDHs) which were chimeras with more than 95% made up of the N-terminal region of Escherichia coli PQQGDH and the rest made up of the C-terminal region of Acinetobacter calcoaceticus PQQGDH was investigated. Among the chimeric PQQGDHs, E97A3 (E. coli 97% and A. calcoaceticus 3%) and E95A5 were found to possess higher thermal stability than parental E. coli PQQGDH. Further detailed characterization of the thermal stability was carried out, focusing on E97A3. E97A3 showed a more than 3-fold and 12-fold increase in half life time at 40 degrees C, compared with the PQQGDHs of E. coli and A. calcoaceticus, respectively. Using transition state theory, the increase in the free energy of inactivation observed in E97A3 was compared with those of the E. coli and A. calcoaceticus parental enzymes. The region responsible for this stabilization was also discussed.
authors.affiliation: Department of Biotechnology, Faculty of Technology, Tokyo University of Agriculture and Technology, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sode
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
authors.forename: S
authors.initials: S
authors.lastname: Ito
authors.forename: K
authors.initials: K
authors.lastname: Matsumura
authors.forename: T
authors.initials: T
authors.lastname: Kikuchi
mesh_terms: D016954:Acinetobacter calcoaceticus / Q000201:enzymology*; D000595:Amino Acid Sequence; D004789:Enzyme Activation; D004795:Enzyme Stability; D004926:Escherichia coli / Q000201:enzymology*; D042843:Glucose 1-Dehydrogenase; D005948:Glucose Dehydrogenases / Q000737:chemistry*; D006358:Hot Temperature; D007700:Kinetics; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000737:chemistry*; D013820:Thermolysin
chemical_list: D011993:Recombinant Fusion Proteins; D005948:Glucose Dehydrogenases; D042843:Glucose 1-Dehydrogenase; D013820:Thermolysin