X-ray and Cryo-EM structures reveal mutual conformational changes of Kinesin and GTP-state microtubules upon binding
Morikawa, M., Yajima, H., Nitta, R., Inoue, S., Ogura, T., Sato, C., Hirokawa, N.(2015) EMBO J 
- PubMed: 25777528 
- DOI: https://doi.org/10.15252/embj.201490588
- Primary Citation of Related Structures:  
3J6H, 3WRD, 3X2T - PubMed Abstract: 
The molecular motor kinesin moves along microtubules using energy from ATP hydrolysis in an initial step coupled with ADP release. In neurons, kinesin-1/KIF5C preferentially binds to the GTP-state microtubules over GDP-state microtubules to selectively enter an axon among many processes; however, because the atomic structure of nucleotide-free KIF5C is unavailable, its molecular mechanism remains unresolved. Here, the crystal structure of nucleotide-free KIF5C and the cryo-electron microscopic structure of nucleotide-free KIF5C complexed with the GTP-state microtubule are presented. The structures illustrate mutual conformational changes induced by interaction between the GTP-state microtubule and KIF5C. KIF5C acquires the 'rigor conformation', where mobile switches I and II are stabilized through L11 and the initial portion of the neck-linker, facilitating effective ADP release and the weak-to-strong transition of KIF5C microtubule affinity. Conformational changes to tubulin strengthen the longitudinal contacts of the GTP-state microtubule in a similar manner to GDP-taxol microtubules. These results and functional analyses provide the molecular mechanism of the preferential binding of KIF5C to GTP-state microtubules.
Organizational Affiliation: 
Department of Cell Biology and Anatomy, The University of Tokyo, Hongo Tokyo, Japan Department of Molecular Structure and Dynamics, Graduate School of Medicine, The University of Tokyo, Hongo Tokyo, Japan.