Fig. 5.

HsCKK domain rigidity mediates local remodelling of its MT-binding site. a Left, chemical-shift perturbations, coloured by differences in ppm, arising from HsCKK_N1492A binding to MTs mapped on the structure of CKK-MT complex (PDB: 5M5C); the CKK domain is depicted in a ribbon representation while the MT surface is shown as a space-filling model; Right, changes of transverse relaxation rates obtained from solution-state NMR CPMG experiments plotted on the 3D structure of the free HsCKK domain; source data are provided as a Source Data file. b HsCKK MT binding is accompanied by contraction of the MT diameter; a single turn of models docked within the aligned 13-protofilament HsCKK and NgCKK C1 reconstructions are shown viewed from the minus end; arrows indicate the irregular shift of individual protofilaments. c Contraction of MT diameter is caused by shrinkage of the distance between adjacent dimers; the distance between the centre of masses of each pair of adjacent B-lattice dimers was measured in 13- and 14-protofilament C1 HsCKK and NgCKK models; all data points are plotted and bars represents mean ± SD; differences between HsCKK and NgCKK models are statistically significant (p < 0.0001, t-test); source data are provided as a Source Data file. d Top, alignment of a single dimer from the NgCKK-tubulin and HsCKK-tubulin C1 models shows HsCKK induces compression and shear between the dimers at its binding site; bottom, RMSD of backbone positions in top panel. e Schematic summarising modifications imposed by HsCKK but not kinesin or NgCKK binding on MT architecture; modifications are exaggerated for clarity