I think the structural formula that you are showing is beta-gamma methyleneATP, not alpha-beta. Both alpha-beta methylene ATP and beta-gamma methylene ATP are "slowly degradable" analogs of ATP (extracellular ATP is easily degraded by ectonucleotidases). They act on purine receptors (purinoceptors) as agonists, having a higher potency than ATP on some of them. Several purinoceptors are readily desensitized by these ATP analogs which, at this stage, act as antagonists rather than agonists. This was the only way to inhibit purinoceptors for a long time. "True" antagonists have been developed or are under development. (See: Burnstock G., 2006, Trends Pharmacol Sci 27, 166)
