Allostery Wiring Map for Kinesin Energy Transduction and its Evolution [Enzymology]

August 8th, 2016 by Richard, J., Kim, E. D., Nguyen, H., Kim, C. D., Kim, S.

How signals between the kinesin active- and cytoskeletal-binding sites are transmitted is an open question and an allosteric question. By extracting correlated evolutionary changes within 700+ sequences, we built a model of residues that are energetically coupled and that define molecular routes for signal transmission. Typically, these coupled residues are located at multiple distal sites and, thus, are predicted to form a complex, nonlinear network that wires together different functional sites in the protein. Of note, our model connected the site for ATP hydrolysis with sites that ultimately utilize its free energy, such as the microtubule-binding site, drug-binding loop-5, and necklinker. To confirm the calculated energetic connectivity between non-adjacent residues, double-mutant cycle analysis was conducted with 22 kinesin mutants. There was a direct correlation between thermodynamic coupling in experiment and evolutionarily-derived energetic coupling. We conclude that energy transduction is coordinated by multiple distal sites in the protein, rather than only being relayed through adjacent residues. Moreover, this allosteric map forecasts how energetic orchestration gives rise to different nanomotor behaviors within the superfamily.