Figure 2
NcdT436S nucleotide hydrolysis kinetics and motility. A, Mant-ADP release upon adding ATP (arrow). Assays performed in HEM100. NcdT436S (black, red curve fit); wild type (WT) (grey, pink curve fit). a.u., arbitrary units. B, Mant-ADP release upon adding excess microtubules (MTs, arrow), then ATP (arrow). Assays performed in HEM50. NcdT436S (black, red curve fit) released ADP with no additions, then, after adding microtubules, released most of the remaining bound ADP; the rest was released by adding ATP. By contrast, wild type (grey, pink curve fit) released about half the bound ADP with microtubules and the rest upon adding ATP. C, Basal and microtubule-stimulated ATPase activity in steady-state assays. NcdT436S (black, red curve fit); wild type (grey, pink curve fit). kcat ± sem. D, In vitro motility. Leading-end microtubule gliding velocity ± sem on NcdT436S and wild type.