Negatively stained images of various motor-track combinations in nucleotide-free conditions. (A) Fields of view showing the typical attachment appearance for Myo51 with or without Rng8/9 bound to bare actin or actin-Tpm. (B) Representative class averages showing bound molecules in each condition. Bars, 20 nm. (C) Histograms of the distance distribution between distal end of the tails of Myo51 or Myo51–Rng8/9 and the axis of the bound actin or actin-Tpm filament. Myo51 with actin, n = 619; Myo51 with actin-Tpm, n = 580; Myo51–Rng8/9 with actin, n = 670; Myo51–Rng8/9 with actin-Tpm, n = 597. (D and E) Myo51–Rng8/9 cross-links and bundles actin-Tpm filaments. Examples showing actin-Tpm cross-linked by Myo51–Rng8/9 in the absence (D) or presence (E) of MgATP. Bars, 50 nm.