title: Local structural changes in tropomyosin detected by a trypsin-probe method.
abstract: Structural changes in tropomyosin from rabbit skeletal muscle were studied by the tryptic digestion method, which is an application of the quantitative enzyme-probe method recently developed by Ueno and Harrington [Ueno, H., & Harrington, W.F. (1984) J. Mol. Biol. 173, 35-61]. Effects of ionic strength, temperature, and an interchain disulfide bond at Cys-190 on the structure of tropomyosin were examined. A region of high susceptibility to trypsin was found to be localized in the middle portion of the molecule, and its susceptibility increased on lowering ionic strength and/or raising temperature. With the introduction of a disulfide bond at Cys-190, cleavage on the N-terminal side of Cys-190 was accelerated. The results suggest that skeletal muscle tropomyosin is flexible in the middle of the molecule in contrast to the flanking N- and C-terminal trypsin-resistant segments.
mesh_terms: D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D008970:Molecular Weight; D009132:Muscles / Q000378:metabolism; D010446:Peptide Fragments / Q000032:analysis; D011487:Protein Conformation; D011817:Rabbits; D013816:Thermodynamics; D014335:Tropomyosin / Q000378:metabolism*; D014357:Trypsin / Q000378:metabolism*
chemical_list: D010446:Peptide Fragments; D014335:Tropomyosin; D014357:Trypsin