title: K+ is an indispensable cofactor for GrpE stimulation of ATPase activity of DnaK x DnaJ complex from Thermus thermophilus.
abstract: K+ is an indispensable cofactor for ATPase activity of eukaryotic cytosolic Hsp70 chaperone systems which lack a GrpE homolog. In the case of the bacterial Hsp70 (DnaK) system, GrpE, a nucleotide exchange factor, stimulates ATPase activity but little is known about the effect of K+. Here, we have cloned a grpE gene from a thermophile, Thermus thermophilus, and purified a homodimeric GrpE protein. Using proteins of this bacterium, we found that the GrpE stimulation of ATPase activity of DnaK x DnaJ complex was absolutely dependent on the presence of K+.
authors.affiliation: Research Laboratory of Resources Utilization, Tokyo Institute of Technology, Yokohama, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Motohashi
authors.forename: M
authors.initials: M
authors.lastname: Yohda
authors.forename: M
authors.initials: M
authors.lastname: Odaka
authors.forename: M
authors.initials: M
authors.lastname: Yoshida
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D003001:Cloning, Molecular; D019281:Dimerization; D004357:Drug Synergism; D029968:Escherichia coli Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000187:drug effects / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D008969:Molecular Sequence Data; D011188:Potassium / Q000502:physiology*; D016963:Thermus thermophilus / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; C494635:DnaJ protein, E coli; D029968:Escherichia coli Proteins; C068113:GrpE protein, Bacteria; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D000251:Adenosine Triphosphatases; C063842:dnaK protein, E coli; D011188:Potassium