Study on the chaperone properties of conserved GTPases

Abstract

As a large family of hydrolases, GTPases are widespread in cells and play the very important biological function of hydrolyzing GTP into GDP and inorganic phosphate through binding with it. GTPases are involved in cell cycle regulation, protein synthesis, and protein transportation. Chaperones can facilitate the folding or refolding of nascent peptides and denatured proteins to their native states. However, chaperones do not occur in the native structures in which they can perform their normal biological functions. In the current study, the chaperone activity of the conserved GTPases of Escherichia coli is tested by the chemical denaturation and chaperone-assisted renaturation of citrate synthase and α-glucosidase. The effects of ribosomes and nucleotides on the chaperone activity are also examined. Our data indicate that these conserved GTPases have chaperone properties, and may be ancestral protein folding factors that have appeared before dedicated chaperones.

Key words： protein folding; chaperone; conserved GTPase

References

[1] Anfinsen, C.B., Haber, E., Sela, M., and White, F.H. Jr. (1961). The kinetics of formation of native ribonuclease during oxidation of the reduced polypeptide chain. Proc Natl Acad Sci U S A 47, 1309-1314 13683522.
[2] Buskiewicz, I., Deuerling, E., Gu, S.Q., J?ckel, J., Rodnina, M.V., Bukau, B., and Wintermeyer, W. (2004). Trigger factor binds to ribosome-signal-recognition particle (SRP) complexes and is excluded by binding of the SRP receptor. Proc Natl Acad Sci U S A 101, 7902-7906 15148364.
[3] Caldas, T., Laalami, S., and Richarme, G. (2000). Chaperone properties of bacterial elongation factor EF-G and initiation factor IF2. J Biol Chem 275, 855-860 10625618.
[4] Caldas, T.D., El Yaagoubi, A., and Richarme, G. (1998). Chaperone properties of bacterial elongation factor EF-Tu. J Biol Chem 273, 11478-11482 9565560.
[5] Caldon, C.E., Yoong, P., and March, P.E. (2001). Evolution of a molecular switch: universal bacterial GTPases regulate ribosome function. Mol Microbiol 41, 289-297 11489118.
[6] Deuerling, E., Schulze-Specking, A., Tomoyasu, T., Mogk, A., and Bukau, B. (1999). Trigger factor and DnaK cooperate in folding of newly synthesized proteins. Nature 400, 693-696 10458167.
[7] Ellis, R.J. (1990). The molecular chaperone concept. Semin Cell Biol 1, 1-9 1983265.
[8] Ellis, R.J. (1993). The general concept of molecular chaperones. Philos Trans R Soc Lond B Biol Sci 339, 257-261 8098529.
[9] Ellis, R.J., and Hemmingsen, S.M. (1989). Molecular chaperones: proteins essential for the biogenesis of some macromolecular structures. Trends Biochem Sci 14, 339-342 2572080.
[10] Genevaux, P., Keppel, F., Schwager, F., Langendijk-Genevaux, P.S., Hartl, F.U., and Georgopoulos, C. (2004). In vivo analysis of the overlapping functions of DnaK and trigger factor. EMBO Rep 5, 195-200 14726952.
[11] Gu, S.Q., Peske, F., Wieden, H.J., Rodnina, M.V., and Wintermeyer, W. (2003). The signal recognition particle binds to protein L23 at the peptide exit of the Escherichia coli ribosome. RNA 9, 566-573 12702815.
[12] Hartl, F.U., and Hayer-Hartl, M. (2009). Converging concepts of protein folding in vitro and in vivo. Nat Struct Mol Biol 16, 574-581 19491934.
[13] Hendrick, J.P., and Hartl, F.U. (1993). Molecular chaperone functions of heat-shock proteins. Annu Rev Biochem 62, 349-384 8102520.
[14] Jakob, U., Gaestel, M., Engel, K., Buchner, J. (1993). Small heat shock proteins are molecular chaperones. J Biol Chem 268, 1517-1520 .
[15] Kramer, G., Boehringer, D., Ban, N., and Bukau, B. (2009). The ribosome as a platform for co-translational processing, folding and targeting of newly synthesized proteins. Nat Struct Mol Biol 16, 589-597 19491936.
[16] Kudlicki, W., Coffman, A., Kramer, G., and Hardesty, B. (1997). Renaturation of rhodanese by translational elongation factor (EF) Tu. Protein refolding by EF-Tu flexing. J Biol Chem 272, 32206-32210 9405422.
[17] Leipe, D.D., Wolf, Y.I., Koonin, E.V., and Aravind, L. (2002). Classification and evolution of P-loop GTPases and related ATPases. J Mol Biol 317, 41-72 11916378.
[18] Maier, R., Scholz, C., and Schmid, F.X. (2001). Dynamic association of trigger factor with protein substrates. J Mol Biol 314, 1181-1190 11743733.
[19] Márquez, V., Wilson, D.N., Tate, W.P., Triana-Alonso, F., and Nierhaus, K.H. (2004). Maintaining the ribosomal reading frame: the influence of the E site during translational regulation of release factor 2. Cell 118, 45-55 15242643.
[20] Nissen, P., Hansen, J., Ban, N., Moore, P.B., and Steitz, T.A. (2000). The structural basis of ribosome activity in peptide bond synthesis. Science 289, 920-930 10937990.
[21] Sato, A., Kobayashi, G., Hayashi, H., Yoshida, H., Wada, A., Maeda, M., Hiraga, S., Takeyasu, K., and Wada, C. (2005). The GTP binding protein Obg homolog ObgE is involved in ribosome maturation. Genes Cells 10, 393-408 15836769.
[22] Sayed, A., Matsuyama, S., and Inouye, M. (1999). Era, an essential Escherichia coli small G-protein, binds to the 30S ribosomal subunit. Biochem Biophys Res Commun 264, 51-54 10527840.
[23] Suzuki, H., Ueda, T., Taguchi, H., and Takeuchi, N. (2007). Chaperone properties of mammalian mitochondrial translation elongation factor Tu. J Biol Chem 282, 4076-4084 17130126.
[24] Teter, S.A., Houry, W.A., Ang, D., Tradler, T., Rockabrand, D., Fischer, G., Blum, P., Georgopoulos, C., and Hartl, F.U. (1999). Polypeptide flux through bacterial Hsp70: DnaK cooperates with trigger factor in chaperoning nascent chains. Cell 97, 755-765 10380927.
[25] Wang, C.C. (2004). Protein folding and molecular chaperones. Bull Biol 39, 1-6 . (In Chinese)