title: Cold-active DnaK of an Antarctic psychrotroph Shewanella sp. Ac10 supporting the growth of dnaK-null mutant of Escherichia coli at cold temperatures.
abstract: Shewanella sp. Ac10 is a psychrotrophic bacterium isolated from the Antarctica that actively grows at such low temperatures as 0 degrees C. Immunoblot analyses showed that a heat-shock protein DnaK is inducibly formed by the bacterium at 24 degrees C, which is much lower than the temperatures causing heat shock in mesophiles such as Escherichia coli. We found that the Shewanella DnaK (SheDnaK) shows much higher ATPase activity at low temperatures than the DnaK of E. coli (EcoDnaK): a characteristic of a cold-active enzyme. The recombinant SheDnaK gene supported neither the growth of a dnaK-null mutant of E. coli at 43 degrees C nor lambda phage propagation at an even lower temperature, 30 degrees C. However, the recombinant SheDnaK gene enabled the E. coli mutant to grow at 15 degrees C. This is the first report of a DnaK supporting the growth of a dnaK-null mutant at low temperatures.
authors.affiliation: Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Yoshimune
authors.forename: Andrey
authors.initials: A
authors.lastname: Galkin
authors.forename: Ljudmila
authors.initials: L
authors.lastname: Kulakova
authors.forename: Tohru
authors.initials: T
authors.lastname: Yoshimura
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Esaki
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000502:physiology*; D000595:Amino Acid Sequence; D000864:Antarctic Regions; D001426:Bacterial Proteins / Q000502:physiology*; D003001:Cloning, Molecular; D003080:Cold Temperature; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000502:physiology*; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D018840:HSP70 Heat-Shock Proteins / Q000502:physiology*; D015151:Immunoblotting; D018832:Molecular Chaperones / Q000502:physiology*; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D020592:Shewanella / Q000502:physiology*; D013696:Temperature; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D018832:Molecular Chaperones; D011994:Recombinant Proteins; D000251:Adenosine Triphosphatases; C115251:DnaK protein, Brevibacillus choshinensis; C063842:dnaK protein, E coli