Adenylyl cyclases (ACs) are promising pharmacological targets for treating heart failure, cancer, and psychosis. Ribose-substituted nucleotides have been reported as a potent family of AC inhibitors. In silico analysis of the docked conformers of such nucleotides in AC permits assembly of a consistent, intuitive QSAR model with strong correlation relative to measured pK(i) values. Energy decomposition suggests that the MANT group effects an AC conformational transition upon ligand binding.