GTP cyclohydrolase IB, replaces FolE under conditions of zinc starvation

GTP cyclohydrolase IB, required for the initial step of queuosine synthesis ([SW|tRNA modification]), replaces [[protein|FolE]] under conditions of zinc starvation

biosynthesis of folate

biosynthesis of folate and queuosine

GTP + H₂O = formate + 2-amino-4-hydroxy-6-(erythro-1,2,3-trihydroxypropyl)-dihydropteridine triphosphate (according to Swiss-Prot)

GTP + H₂O --> 7,8-dihydroneopterin 3'-triphosphate + formate + H⁺ (according to UniProt)