Hand-over-hand 8 nm steps, ATP hydrolysis cycle & force-velocity curve
Kinesin-1 walks processively along microtubule α/β-tubulin lattice (8 nm periodicity = one tubulin dimer). Each 8 nm step consumes one ATP (hydrolysis: ATP → ADP + Pᵢ, ΔG ≈ −54 pN·nm). Velocity follows Michaelis-Menten kinetics v = v_max·[ATP]/(K_m+[ATP]) modified by load: stall force F_s ≈ 6 pN. The force-velocity relationship v(F) = v₀(1−F/F_s) with P_max = F_s·v₀/4 ≈ 1.5 pN·nm/ms.