Multiple sequence alignment of RpiB crystal structures from different organisms. C. immitis is from the current study (PDB ID 3QD5). S. pu is Streptococcus pneumonia (2PPW, no primary citation), V. pa is Vibrio parahaemolyticus (3ONO, no primary citation), T. ma is Thermotoga maritima (PDB ID 1O1X) , E. co is E. coli (1NN4) , C. th is Clostridium thermocellum (3HEE) , T. cr is Trypanosoma cruzi (3K8C) . Mycobacterium tuberculosis contains different active site residues and utilizes a variant catalytic mechanism [5, 22], and thus the sequence is not shown in the alignment. Residues marked with an * are involved in recognition of the phosphate moiety of ribose-5-phosphate. Numbering is based on the C. immitis sequence.