Probing Open Conformation of GroEL Rings by Cross-linking Reveals Single and Double Open Ring Structures of GroEL in ADP and ATP

The ATPase activity of molecular chaperone HSP60 is inhibited by immunosuppressant mizoribine

“…The ATP hydrolysis activity correlates with cochaperone [18,31]. Some studies suggested that the ATPase activity of GroEL is suppressed by the binding of GroES and stimulated by the substrate protein [40][41][42]. Our results found that the dissociation of HSP10 was inhibited by mizoribine ( Figure 6).…”

“…The GroES binding site mostly overlaps with the substrate protein binding site at the apical domain [26]. The GroEL mutations that lack the double open ring conformation can bind GroES, while the ATP hydrolysis cannot bind the substrate protein [42]. In contrast, our results suggested that the binding of the substrate protein to HSP60 was not trapped by mizoribine (Figure 2(c)).…”

Single-molecule Observation of Protein Folding in Symmetric GroEL-(GroES)2 Complexes

“…Recently, it has been shown that ADP remains in the GroEL ring even after GroES has detached from the same ring (40,41). Also, it has been demonstrated that ADP prevents the association of ATP (42) and the second GroES with the trans-ring (13,14). As indicated in our previous report (15), the binding of the denatured protein to the trans-ring will facilitate the dissociation of ADP from the trans-ring and the formation of the football-shaped complex.…”

“…In contrast, the existence of the football-shaped complex in the presence of ATP has been suggested by electron microscopic observation (8 -10) and biochemical experiments (11)(12)(13). In addition, our recent studies have shown that the football-shaped and bullet-shaped complexes coexist during the reaction cycle (14), and the formation of the football-shaped complex is promoted by increases in the ATP/ADP ratio (14) and the concentration of denatured protein (15).…”

Crystal structure of the human mitochondrial chaperonin symmetrical football complex

“…Notably, mHsp60 assembles into a double-ring structure that binds two mHsp10 molecules, one at each end of the tetradecamer, forming the symmetric chaperonin complex [mHsp60 14-(mHsp10 7 ) 2 complex], previously termed the "football complex." This complex was found to play an important role in the chaperonin protein-folding reaction cycle (34)(35)(36)(37)(38)(39)(40)(41). To distinguish between the two symmetric halves of the football, we called one of the halves the "north pole" and the other the "south pole" (the full nomenclature of subunits is provided in Fig.…”