Localization of a new proteolytic site accessible in oxidized myosin rod.
We have compared the proteolysis pattern of reduced and oxidized myosin rods in which the five pairs of SH-groups were interchain crosslinked by employing CuCl2 or 5,5'-dithiobis-2-nitrobenzoate. In the tryptic digest of oxidized rod three new fragments appeared on SDS-polyacrylamide gel electrophoresis (chain masses of 100, 45, and 25 kDa). Based on the N-terminal sequences of the isolated peptides, it is concluded that oxidation creates a new cleavage site 102 residues away from the N-terminus of the rod, in the vicinity of one of the modified SH-groups (Cys-108). This observation indicates that S-S crosslinking of myosin rod leads to a local unfolding of the coiled-coil structure.
D000595:Amino Acid Sequence; D000818:Animals; D003300:Copper / Q000494:pharmacology; D004220:Disulfides / Q000378:metabolism; D004228:Dithionitrobenzoic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D009218:Myosins / Q000378:metabolism*; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000302:isolation & purification / Q000378:metabolism; D011817:Rabbits; D014357:Trypsin / Q000378:metabolism*
D004220:Disulfides; D010446:Peptide Fragments; D003300:Copper; D004228:Dithionitrobenzoic Acid; C028419:cuprous chloride; D014357:Trypsin; D009218:Myosins