The use of aryl azido ATP analogs as photoaffinity labels for myosin ATPase

The synthesis of ATP analogs containing a photoactive aryl azido grouping coupled to the 3' hydroxyl of ATP is described. The potential effectiveness of these analogs in the investigation of nucleotide-binding regions is outlined and this effectiveness demonstrated by their photodependent inhibition of subfragment 1 ATPase. The use of 14C-labeled azido ATP demonstrates an almost stoichiometric covalent binding of the analog. Because of their potential application to other systems, a number of reactions describing the reactivity of the 3' hydroxyl of the nucleotide ribose are outlined in an Appendix.