Photochemical probes of the active site of myosin. Irradiation of trapped 3'-O-(4-benzoyl)benzoyladenosine 5'-triphosphate labels the 50-kilodalton heavy chain tryptic peptide.

Abstract

3'-0-(4-Benzoyl)benzoyl-ATP (Bz,ATP), an analog of ATP containing a photoreactive benzophenone moiety, was used as a probe of the ATP binding site of myosin subfragment 1 (SF,).The inactivation of SF, NK+-EDTA ATPase by the bifunctional thiol crosslinking system cobalt(II)/cobalt(III) phenanthroline complexes was enhanced by BzzATP to the same degree as by ATP.This treatment resulted in the stable trapping of BzzATP at the active site in nearly stoichiometric amounts in a manner exactly analogous to ATP (Wells, J.