title: Molecular flexibility in microtubule proteins: proton nuclear magnetic resonance characterization.
abstract: Bovine microtubule protein preparations have been examined by proton nuclear magnetic resonance (1H NMR) spectroscopy at 270 MHz. Sharp resonances have been identified as deriving from microtubule-associated proteins. These resonances persist after self-assembly of microtubule protein. Brief tryptic treatment of assembled microtubules, specifically cleaving the microtubule-associated protein HMW2 (Mr = 270 000), releases the pendant portion of HMW2 (Mr = 240 000), three-quarters of which is in a flexible conformation. Isolated tau protein and HMW2 protein both show substantial flexibility; on recombination with tubulin dimer, tau shows considerable decrease in flexibility whereas HMW2 is unaffected. The observations may have important implications for the interactions between microtubules and other cytoskeletal structures.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001923:Brain Chemistry; D002417:Cattle; D002942:Circular Dichroism; D009682:Magnetic Resonance Spectroscopy; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D011487:Protein Conformation; D011506:Proteins; D014404:Tubulin
chemical_list: D000596:Amino Acids; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D011506:Proteins; D014404:Tubulin