Catalyzes the first committed step of 'de novo purine biosynthesis from glutamine. Required for chloroplast biogenesis and cell division. Confers sensitivity to the phenyltriazole acetic acid compound [5-(4-chlorophenyl)-1-isopropyl-1H-[1,2,4]triazol-3-yl]-acetic acid (DAS734), a bleaching herbicide. 5-phospho-beta-D-ribosylamine + diphosphate + L-glutamate = 5-phospho-alpha-D-ribose 1-diphosphate + H2O + L-glutamine Binds 1 [4Fe-4S] cluster per subunit. Binds 1 Mg(2+) ion per subunit. Inhibited by the phenyltriazole acetic acid compound [5-(4-chlorophenyl)-1-isopropyl-1H-[1,2,4]triazol-3-yl]-acetic acid (DAS734), a bleaching herbicide. Purine metabolism; IMP biosynthesis via de novo pathway; N(1)-(5-phospho-D-ribosyl)glycinamide from 5-phospho-alpha-D-ribose 1-diphosphate: step 1/2. Mostly expressed in leaves, and, to a lower extent, in cotyledons. Strong growth retardation and severe chlorosis in leaves; white leaves, but green cotyledons. Leaves missing the palisade mesophyll layer, due to reduced cell number and size. Abnormal thylakoid membrane in chloroplasts, probably due to photo-oxidative damage. Defective in protein import into chloroplasts. In the C-terminal section; belongs to the purine/pyrimidine phosphoribosyltransferase family.