Ribosomal protein L2 associates with E. coli HtpG and activates its ATPase activity.
Although eukaryotic Hsp90 has been studied extensively, the function of its bacterial homologue HtpG remains elusive. Here we report that 50S ribosomal protein L2 was found as an associated protein with His-tagged HtpG from Escherichia coli cultured in minimum medium at 45 °C. L2 specifically activated ATPase activity of HtpG, but other denatured proteins did not. The analysis using domain derivatives of HtpG and L2 showed that C-terminal domain of L2 and the middle to C-terminal domain of HtpG are important for interaction. At physiological salt concentration, L2 was denatured state and was recognized by HtpG as well as other chaperones, DnaK/DnaJ/GrpE and GroEL/GroES. The ATPase of HtpG at increasing concentration of L2 indicated that an L2 molecule bound to a dimer HtpG with apparent K(D) of 0.3 μM at 100mM KCl and 3.3 μM at 200 mM KCl.
Motojima-Miyazaki
Yuko
Y
Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
Yoshida
Masasuke
M
Motojima
Fumihiro
F
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D004789:Enzyme Activation; D004926:Escherichia coli / Q000201:enzymology* / Q000254:growth & development; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006868:Hydrolysis; D011189:Potassium Chloride / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012269:Ribosomal Proteins / Q000378:metabolism*
D029968:Escherichia coli Proteins; D018841:HSP90 Heat-Shock Proteins; C489352:HtpG protein, E coli; D012269:Ribosomal Proteins; C029466:ribosomal protein L2; D011189:Potassium Chloride; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases