Multiple sequence alignment of three families of R2K ATP-grasp modules with known ATP-grasp structures. Proteins are labeled with their species abbreviations and GenBank index numbers along with gene names for human and viral homologs. PDB identifiers, colored in orange, are given in lieu of gene names where applicable. Secondary structures are depicted above alignment with loop regions shown as lines, β-strands (S1-S9) shown as green arrows and α-helices shown as orange cylinders. The coloring of the alignment is based on 75% consensus shown below the alignment, using the following scheme: h, hydrophobic (shaded in yellow); s, small (shaded in light green); l, aliphatic (shaded in yellow); p, polar (shaded in light blue); +, positively charged; b, big (shaded in gray); a, aromatic (shaded in yellow); c, charged (shaded in purple). Predicted catalytic residues are colored in white and shaded in red. Species abbreviations: Acas, Acanthamoeba castellanii; Achl, Arthrobacter chlorophenolicus; Adel, Auricularia delicata; ApMV, Acanthamoeba polyphaga moumouvirus; Asp., Acaryochloris sp.; BPMyrna, Mycobacterium phage Myrna; BPRSL1, Ralstonia phage RSL1; Bsp., Brenneria sp.; Cfla, Chthoniobacter flavus; Cmin, Chamaesiphon minutus; Einv, Entamoeba invadens; Elat, Eutypa lata; Esp., Eggerthella sp.; Fnec, Fusobacterium necrophorum; Gint, Giardia intestinalis; Gsp., Geitlerinema sp.; Hsap, Homo sapiens; Krac, Ktedonobacter racemifer; Lbic, Laccaria bicolor; Llon, Legionella longbeachae; Lsab, Lachnoanaerobaculum saburreum; Lsp., Labrenzia sp.; Mmar, Microscilla marina; Mxan, Myxococcus xanthus; Ngru, Naegleria gruberi; Nvec, Nematostella vectensis; PVs, Pithovirus sibericum; Pamy, Pseudomonas amygdali; Pmar, Perkinsus marinus; Pmar, Planctomyces maris; Scer, Saccharomyces cerevisiae; Smob, Streptomyces mobaraensis; Ssp., Streptomyces sp.; Ster, Sebaldella termitidis; Tazo, Treponema azotonutricium; Tbry, Treponema bryantii; Tvag, Trichomonas vaginalis. Other abbreviations: GS, glutathione synthase; BC, biotin carboxylase.