title: Sequence analysis of an exceptionally conserved operon suggests enzymes for a new link between histidine and purine biosynthesis.
authors.forename: M Y
authors.initials: MY
authors.lastname: Galperin
authors.forename: E V
authors.initials: EV
authors.lastname: Koonin
mesh_terms: D000878:Anthranilate Synthase; D004798:Enzymes / Q000235:genetics*; D006639:Histidine / Q000378:metabolism; D019884:Nitrogenous Group Transferases; D010710:Phosphates / Q000378:metabolism; D011687:Purines / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014166:Transferases / Q000235:genetics
chemical_list: D004798:Enzymes; D010710:Phosphates; D011687:Purines; D006639:Histidine; D014166:Transferases; D019884:Nitrogenous Group Transferases; D000878:Anthranilate Synthase; C020655:anthranilate synthase, glutamine amidotransferase subunit