Are cytoplasmic microtubules heteropolymers?
Colchicine-binding protein, considered to be microtubule protein, was purified from chick embryo brain by column chromatography in one step on DEAE-Sephadex. The active colchicine-binding unit is a dimer, MW 115,000 +/- 5000, which is composed of two nonidentical monomeric units. The two subunits are separable by urea-acrylamide gel electrophoresis after they have been reduced and acetylated. Sodium dodecyl sulfate-acrylamide gel electrophoresis indicates that the subunits both have molecular weights of 55,000 +/- 2000. The amino-acid compositions of the two subunits showed statistically significant differences in six amino-acid residues. These results indicate that colchicine-sensitive cytoplasmic microtubules are heteropolymers.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001345:Autoradiography; D001923:Brain Chemistry; D002642:Chick Embryo; D002852:Chromatography, Ion Exchange; D003078:Colchicine; D003720:Densitometry; D004586:Electrophoresis; D008870:Microtubules / Q000032:analysis*; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000032:analysis* / Q000302:isolation & purification; D011108:Polymers / Q000032:analysis*; D011485:Protein Binding; D014316:Tritium
D000596:Amino Acids; D009419:Nerve Tissue Proteins; D011108:Polymers; D014316:Tritium; D003078:Colchicine