Figure 1.

(A) The 7-deazaguanine modification gene cluster in CAjan bacteriophage (NC_028776.1) located in the region 28 621–34 560 bp. Genes are colored by function: purple are genes involved in preQ₀ synthesis, orange is the gene coding for the preQ₀ transporter, blue is the dpdA gene and in white are genes coding for unknown functions. Numbers correspond to gene product numbers from NC_028776. On the right side, there is a 500 bp grey rectangle for size reference and rest of the Figure is drawn to this scale. (B) Biosynthesis pathway of preQ₀. The biosynthesis starts with GTP which is transformed to preQ₀ by enzymes FolE, QueD, QueE and QueC. Alternatively, YhhQ can transport preQ₀ from the outside. The last step is DpdA enzyme that exchanges targeted G bases with the preQ₀.