Purification and assembly in vitro of tubulin from Trypanosoma brucei brucei.
MacRae TH., Gull K.
Trypanosome tubulin was purified to near homogeneity by chromatography on DEAE-Sephadex, Amicon filtration and assembly-disassembly in vitro. Polymerization of the tubulin in vitro yielded long, structurally normal, microtubules and some sheet structures on addition of GTP and incubation at 37 degrees C, in either the presence or the absence of Mg2+. Tubulin assembly was disrupted by glycerol and a selection of microtubule-reactive drugs. Immunological analysis of the purified tubulin revealed tyrosinated and acetylated alpha-tubulin, in addition to defining the migration characteristics of the alpha- and beta-tubulin on one-dimensional SDS/polyacrylamide gels. This is the first isolation of trypanosome tubulin with the ability to form structurally normal microtubules independent of the addition of taxol or nucleating microtubule fragments. The development of the purification procedure thus provides an important step for subsequent study of microtubule-associated protein-tubulin and plasma-membrane-microtubule cytoskeleton interactions of trypanosomes, and increases the potential for development of tubulin-based anti-trypanosome drugs.