7-Cyano-7-deazaguanine

7-Cyano-7-deazaguanine is a key purine precursor molecule in the 7-deazaguanine pathway. 7-Cyano-7-deazaguanine acts as a substrate for transglycosylases to participate in base exchange reactions, replacing native guanine in nucleic acids to generate 7-deazaguanine-modified DNA or tRNA; it can be catalyzed by QueC/ToyM to form the 7-amido-7-deazaguanine (ADG) intermediate for further involvement in subsequent biosynthesis. 7-Cyano-7-deazaguanine is applicable to studies related to translation regulation^[1][2][3]. In Vitro:7-Cyano-7-deazaguanine (preQ0) serves as a substrate for a variety of purified enzymes: Bacillus subtilis QueC generates it from CDG relying on K163 and R204; Pyrococcus arcTGT inserts it into archaeal tRNA; phage DpdA1 integrates it into specific DNA sequences; Salmonella enterica serovar Montevideo DpdC converts preQ0-modified DNA into dADG-modified DNA; and it can be transported across the inner membrane by recombinant Escherichia coli QPTR^[1].
7‑Cyano‑7‑deazaguanine (preQ0) is incorporated into pUC19 DNA as dPreQ0 and subsequently converted to dADG by DpdC from Salmonella enterica serovar Montevideo^[3].
7‑Cyano‑7‑deazaguanine (preQ0) is the final product of the two-step conversion of CDG to ADG catalyzed by ATP-dependent ToyM, with a half-life of approximately 4 min for the formation of this product from ADG^[2].