Controversy exists over whether the chaperonin GroEL forms a GroEL–(GroES)2 complex (football-shaped complex) during its reaction cycle. We have revealed previously the existence of the football-shaped complex in the chaperonin reaction cycle using a FRET (fluorescence resonance energy transfer) assay [Sameshima, Ueno, Iizuka, Ishii, Terada, Okabe and Funatsu (2008) J. Biol. Chem. 283, 23765–23773]. Although denatured proteins alter the ATPase activity of GroEL and the dynamics of the GroEL–GroES interaction, the effect of denatured proteins on the formation of the football-shaped complex has not been characterized. In the present study, a FRET assay was used to demonstrate that denatured proteins facilitate the formation of the football-shaped complex. The presence of denatured proteins was also found to increase the rate of association of GroES to the trans-ring of GroEL. Furthermore, denatured proteins decrease the inhibitory influence of ADP on ATP-induced association of GroES to the trans-ring of GroEL. From these findings we conclude that denatured proteins facilitate the dissociation of ADP from the trans-ring of GroEL and the concomitant association of ATP and the second GroES.
Denatured proteins facilitate the formation of the football-shaped GroEL–(GroES)2 complex
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Tomoya Sameshima, Ryo Iizuka, Taro Ueno, Takashi Funatsu; Denatured proteins facilitate the formation of the football-shaped GroEL–(GroES)2 complex. Biochem J 15 April 2010; 427 (2): 247–254. doi: https://doi.org/10.1042/BJ20091845
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