Figure 3.

Comparative genomic evidence. (A) Clustering of COG1634 and COG2098 genes with pterin and cofactor biosynthetic related genes. Abbreviation not found in the text: FolP-like, dihydropteroate synthase-like enzyme homologous to the bacterial folate enzyme FolP but of unknown function;⁵⁹ MptG, β-ribofuranosylaminobenzene 5′-phosphate synthase;⁶⁰ FolM, alternative dihydrofolate reductase;⁶¹ F420-lig, coenzyme F420-0: l-glutamate ligase.⁶² (B) The archaeal DHNA (MptD) tetramer with bound pterin ring mimic (PDB 2OGF). The individual subunits of MJ0408 are shown with differently colored cartoons, the bound ligand 8-oxoguanine with orange carbons. (C) Putative active site of the archaeal DHNA with manually docked neopterin. The MptD structure is from PDB 2IEC, and the neopterin ligand (orange carbons) is from PDB 2O90 (in alternative conformation B). The active site residues contributed by three different subunits are shown with green, cyan, and magenta carbons, respectively (as in panel B and Supplemental Figure 3).