Brain myosin assembly: characterization of aggregation-competent fragments by antibodies

Six different monoclonal antibodies raised against pig brain myosin were used to characterize aggregation-competent fragments of the rod portion of bovine brain myosin. As a prerequisite, the antibody-binding regions in pig brain myosin were determined, and recognition of the same epitopes in the bovine protein was ascertained. A combination of electron microscopy on rotary shadowed myosin: antibody complexes, immunoblotting of proteolytic rod fragments and immunoelectron microscopy with gold-conjugated antibodies allowed for the following conclusions: (1) Rod fragments lacking as much as 24 kDa at the N-terminal, and approximately 16 kDa at the C-terminal end are still aggregation competent. (2) Brain myosin rods aggregate in an antiparallel fashion. These data contribute to our knowledge on structural features of brain myosin relevant to its presumed functions in brain cells.