Cryo-EM (A & D) and cryo-ET (C, F & G) of microtubules decorated with Eg5-2MTH chimeras, after incubation with either a Au(I)Cl solution (A, C & D) or a ZnSO4 solution (F, G). Generally, the zinc solution (F, G) appears to better preserve the microtubule-motor complex structure than the gold solution (A, C & D). The visibility of the gold clusters varies slightly with the EM defocus chosen. Panel A was recorded at −4.5 µm defocus while panel D was taken at about −2.5 µm (see the corresponding diffraction patterns in B and E respectively). The MTH gold clusters form a stronger signal than the MTH-zinc particles, however, the intrinsic order of the motor-microtubule complex is changed visibly when incubated with gold (see tomographic ~9 nm slice in C) while the zinc clusters line up nicely (F, G).