TMAO regulates the rigidity of kinesin-propelled microtubules

We demonstrate that the rigidity of the microtubules (MTs), propelled by kinesins in an in vitro gliding assay, can be modulated using the deep-sea osmolyte trimethylamine N-oxide (TMAO). By varying the concentration of TMAO in the gliding assay, the rigidity of the MTs is modulated over a wide range. By employing this approach, we are able to reduce the persistence length of MTs, a measure of MT rigidity, [~]8 fold using TMAO of the concentration of 1.5 M. The rigidity of gliding MTs can be restored by eliminating the TMAO from the gliding assay. This work offers a simple strategy to regulate the rigidity of kinesin-propelled MTs in situ and would widen the applications of biomolecular motors in nanotechnology, materials science, and bioengineering.