Ability of the L11-α4 junction to discriminate microtubules examined with cryo-EM. (A) Sequence alignment of L11 and α4 region in KIF5C, the L11-α4 junction mutant, and KIF1A. (B–E) Comparison of cryo-EM density maps around the L11-α4 junction between KIF5C(ø)–MT(GDP) and KIF5C(PNP)–MT(GDP), viewed from the plus end (B and C) and left side (D and E). (F and G) The candidate amino acid residues proposed to be involved in the interaction between KIF5C and α-tubulin in KIF5C(ø)–MT(GDP) (F) and in KIF5C(PNP)–MT(GDP) (G). See Fig. S5 for the detailed structures of the L11-α4 junction of KIF1A and KIF5C.