title: In vivo and in vitro complementation study comparing the function of DnaK chaperone systems from halophilic lactic acid bacterium Tetragenococcus halophilus and Escherichia coli.
abstract: In this study, we characterized the DnaK chaperone system from Tetragenococcus halophilus, a halophilic lactic acid bacterium. An in vivo complementation test showed that under heat stress conditions, T. halophilus DnaK did not rescue the growth of the Escherichia coli dnaK deletion mutant, whereas T. halophilus DnaJ and GrpE complemented the corresponding mutations of E. coli. Purified T. halophilus DnaK showed intrinsic weak ATPase activity and holding chaperone activity in vitro, but T. halophilus DnaK did not cooperate with the purified DnaJ and GrpE from either T. halophilus or E. coli in ATP hydrolysis or luciferase-refolding reactions under the conditions tested. E. coli DnaK, however, cross-reacted with those from both bacteria. This difference in the cooperation with DnaJ and GrpE appears to result in an inability of T. halophilus DnaK to replace the in vivo function of the DnaK chaperone of E. coli.
authors.affiliation: Laboratory of Microbial Technology, Division of Microbial Science and Technology, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Sugimoto
authors.forename: Kozue
authors.initials: K
authors.lastname: Saruwatari
authors.forename: Chihana
authors.initials: C
authors.lastname: Higashi
authors.forename: Keigo
authors.initials: K
authors.lastname: Tsuruno
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Matsumoto
authors.forename: Jiro
authors.initials: J
authors.lastname: Nakayama
authors.forename: Kenji
authors.initials: K
authors.lastname: Sonomoto
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000502:physiology*; D005816:Genetic Complementation Test; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics / Q000502:physiology; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000502:physiology; D018882:Heat Stress Disorders; D007778:Lactobacillus / Q000737:chemistry*; D018832:Molecular Chaperones; D009154:Mutation
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D018832:Molecular Chaperones; C063842:dnaK protein, E coli