Specific cross-linking of the SH1 thiol of skeletal myosin subfragment 1 to F-actin and G-actin

Recently, we reported that (maleimidobenzoyl)-G-actin (MBS-G-actin), which was resistant to the salt and myosin subfragment 1 (S- 1) induced polymerizations, reacts reversibly and covalently in solution with the S-1 heavy chain at or near the strong F-actin binding region [Bettache, N., Bertrand, R., & Kassab, R. (1989) Proc. Natl. Acad. Sci. U.S.A. 86, 6028-6032]. Here, we have readily converted the MBS-G-actin into MBS-F-actin in the presence of phalloidin and salts