Microtubules exist ubiquitously in eukaryotic cells, constituting key components of the cytoskeleton and playing critical roles in various cellular processes such as signaling, mitosis and intracellular transport. Tubulin is a heterodimer of two globular proteins, α- and β-tubulin. The tubulin heterodimers join lengthwise (polymerize) to form fibrous protofilaments which in turn assemble themselves side by side to yield tube-shaped microtubules. Such super-polymers can reach a length of several μm.
A variety of physical methods have been employed to probe microtubules. These evaluations were, however, biased more toward structural formations or variations using optical- and electron microscopy, X-ray scattering and small-angle neutron scattering. To our knowledge, dynamical studies of the internal fluctuations are lacking.
This project aims to examine the shift in fluctuational dynamics of tubulin in its polymerized state induced by Taxol binding. The aim is to apply quasi-elastic neutron scattering (QENS), specifically the neutron spin-echo technique, to quantify the length- and time-scales for the motions of non-methyl hydrogen atoms in tubulin heterodimers polymerized into microtubules.
This study will inform our understanding of microtubule dynamics and that of protein dynamics in general, particularly protein super polymers.