Design, Synthesis, and Evaluation of Acyclic <i>C-</i>Nucleoside and <i>N</i>-Methylated Derivatives of the Ribitylaminopyrimidine Substrate of Lumazine Synthase as Potential Enzyme Inhibitors and Mechanistic Probes
abolished the affinity for lumazine synthase, thus revealing a critical, yet unexplained, role of the ribitylamino N−H moiety in conferring affinity for the enzyme. In contrast, the N−CH3 replacement resulted in an inhibitor of both lumazine synthase and riboflavin synthase. Replacement of the ribitylamino N−H moiety with epimeric C−F moieties led to inhibition of lumazine synthase and riboflavin synthase