title: Hybridization of rabbit cardiac tropomyosin with nonpolymerizable tropomyosin species.
abstract: Rabbit cardiac tropomyosin was hybridized with its nonpolymerizable form, produced by treatment with carboxypeptidase A, and with a naturally occurring nonpolymerizable tropomyosin from horse platelets. Hybridization was achieved by heating equimolar mixtures to 60 degrees C in the presence of 10 mM dithiothreitol, followed by recooling. Samples of intact and carboxypeptidase-truncated tropomyosins treated in this way show lower viscosities at low ionic strength than predicted assuming random reformation of the coiled coils, suggesting that hybrids formed with one intact COOH-terminus are unable to polymerize normally. Hybridization of cardiac and platelet tropomyosins was detected by observation of the fluorescence of pyrene groups attached to cysteine residues on platelet tropomyosin.
authors.affiliation: Department of Chemistry, University of British Columbia, Vancouver, Canada.
authors.forename: I D
authors.initials: ID
authors.lastname: Clark
authors.forename: L D
authors.initials: LD
authors.lastname: Burtnick
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000737:chemistry; D002268:Carboxypeptidases / Q000378:metabolism; D043422:Carboxypeptidases A; D004229:Dithiothreitol / Q000737:chemistry; D006736:Horses; D006358:Hot Temperature; D046911:Macromolecular Substances; D009206:Myocardium / Q000737:chemistry*; D011487:Protein Conformation; D011817:Rabbits; D013050:Spectrometry, Fluorescence; D014335:Tropomyosin / Q000737:chemistry* / Q000378:metabolism; D014783:Viscosity
chemical_list: D046911:Macromolecular Substances; D014335:Tropomyosin; D002268:Carboxypeptidases; D043422:Carboxypeptidases A; D004229:Dithiothreitol