Stabilization of protein by freeze-drying in the presence of trehalose: a case study of tubulin.

Microtubules, polymers of the heterodimeric protein αβ-tubulin, are indispensable for many cellular activities such as maintenance of cell shape, division, migration, and ordered vesicle transport. In vitro assays to study microtubule functions and their regulation by associated proteins require the availability of assembly-competent purified tubulin. However, tubulin is a thermolabile protein that rapidly converts into non-polymerizing state. For this reason it is usually stored at -80 °C to preserve its conformation and polymerization properties. In this chapter we describe a method for freeze-drying of assembly-competent tubulin in the presence of nonreducing sugar trehalose and methods enabling evaluation of tubulin functions in rehydrated samples.