Fig. 3.

HsCKK is more sensitive to MT lateral curvature than NgCKK. a A transverse slice, viewed from the MT plus end, through 3 protofilaments from the NgCKK-MT 13- and 14- protofilament (pf) models superimposed on the central protofilament. This shows that the adjacent protofilaments adopt a shallower relative angle in 14-protofilament MTs (orange arrows) and reveals the response of NgCKK bound in the interprotofilament valley to this change in lateral protofilament curvature. Top, view of the superimposed protofilament backbone models from the 13- and 14-protofilament structures superimposed on the central protofilament (dotted pink outline); small blue arrows indicate the relatively small displacement of NgCKK from its binding site on 14-protofilament MTs. Bottom, backbone RMSD between the 13- and 14-protofilament models shown on the 13-protofilament model; b schematic depicting the effect of MT protofilament architecture on NgCKK binding. c A transverse slice, viewed from the MT plus end, through three protofilaments from the HsCKK-MT 13- and 14- protofilament models superimposed on the central protofilament. This again shows how the adjacent protofilaments adopt a shallower relatively angle in 14-protofilament MTs (orange arrows) and reveals the response of bound HsCKK to this change in lateral protofilament curvature. Top, view of the superimposed protofilament backbone models from the 13- and 14-protofilament structures superimposed on the central protofilament (dotted pink outline); larger blue arrows indicate the larger displacement of HsCKK from its binding site on 14-protofilament MTs. Bottom, backbone RMSD between the 13- and 14-protofilament models shown on the 13-protofilament model; d schematic depicting the effect of MT protofilament architecture on HsCKK binding