Figure 7. Interaction between the ClpB hexamer and DnaK.
(A) Binding of DnaK is only possible when the MD is tilted (green). DnaK cannot bind when two adjacent MDs occupy a more horizontal position (red) as it would clash with motif 1 of the neighbouring ClpB subunit. (B) Cartoon of an opened-out ClpB ring with two DnaK molecules bound. The MDs involved in DnaK binding are shown in green, and those that cannot bind to DnaK are shown in red. Release of the ends of the MD favours activation of adjacent subunits, and the active cluster can move around the ring in a wave-like manner. The model of DnaK binding to the MD is based on the NMR study in Seyffer et al. (2012).