Synchrotron SAXS data from solutions of kinesin heavy chain in 25 mM HEPES/KOH, 150 mM NaCl, 1 mM MgCl2, 2 mM DTT, pH 7.3 were collected on the BM29 beam line at the ESRF (Grenoble, France) using a Pilatus3 2M detector at a sample-detector distance of 2.8 m and at a wavelength of λ = 0.099186 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). One solute concentration of 0.50 mg/ml was measured at 20°C. 10 successive 1 second frames were collected. The data were normalized to the intensity of the transmitted beam and radially averaged; the scattering of the solvent-blank was subtracted.