STUDIES OF MYOSIN CONFORMATION BY FLUORESCENT TECHNIQUES

The fluorescense of myosin A was quenched by its interaction with 8-anilino-1-naphthalenesulfonate. The quenching is shown to result from a transfer of the excitation energy from myosin chromophores to the adsorbed dye, which fluoresces maximally at 468 nm. This is demonstrated by the fluorescence excitation spectrum of bound 8-anilino-1-naphthalenesulfonate in which the fluorescence intensity with excitation in the 280-nm region is several times larger than that expected from the absorption spectrum of the dye. Native myosin showed a larger transfer than myosin which had been modified by p-mercuribenzoate, EDTA, Cd2+, and Zn2+. The decrease in transfer is attributed to changes in myosin conformation resulting from the modifications. © 1969, American Chemical Society. All rights reserved.