Figure 2.

Detail of HAP40 bound to HTT. HAP40 interacts very tightly with the C-terminal domain of HTT (blue). The C-terminal V371 of HAP40 is inserted into the moiety of HEAT repeats. No disordered insertions are noted in this interface. Note the contrast with the interface of interaction between HAP40 and the HTT cyan domain. The side facing the viewer contains two unmodeled regions in HAP40 (orange dashed lines) and two in HTT (yellow dashed lines). These intrinsically disordered regions (IDRs) are likely to interact in 3D. All alanines in HAP40 have been colored in yellow to note that the C-terminal A-rich region belongs to the part of HAP40 facing away from the core of HTT.