Structural changes of rabbit myosin subfragment 1 altered by malonaldehyde, a byproduct of lipid oxidation.

Rabbit myosin subfragment 1 was allowed to react with malonaldehyde, a byproduct of lipid oxidation in a model system containing the subfragment 1 and malonaldehyde. The modified subfragment 1 was compared to the control, with use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), circular dichorism (CD), Fourier transform infrared spectroscopy (FT-IR), and free amino group measurements. Both the modified and control samples were cleaved with cyanogen bromide (BrCN) treatment, and the BrCN fragments were analyzed by SDS-PAGE with tricine gel. Results from SDS-PAGE suggest that malonaldehyde causes cross-linking or polymerization of the protein during incubation. Malonaldehyde also reduced alpha-helix content (CD), increased random structure (FT-IR), and eliminated some beta-strand structure (FT-IR) in subfragment 1.