Fig. 5: The response of CH1 and CH2 upon nucleotide and substrate binding.
From: Probing the allosteric NBD-TMD crosstalk in the ABC transporter MsbA by solid-state NMR
In the apo state, CH1 is solely interacting with the NBD of its own chain and CH2 with the other NBD’. Upon binding of Hoechst 33342, MsbA moves to an occluded conformation, and a large chemical shift change is observed within the domain-swapped CH2 (Hoechst 33342 state). It triggers conformational changes within the NBD which supports nucleotide binding. Trapping MsbA in an ATP hydrolysis transition state by ADP•Vi (ADP•Vi state), a conformational change from the inward- to the outward-facing conformation occurs. Here, a chemical shift change in CH1 is observed. ADP•Vi trapping of the Hoechst 33342 state converges towards the ADP•Vi state.
