Catalyzes the synthesis of GMP from XMP. ATP + H2O + L-glutamine + XMP = AMP + diphosphate + GMP + 2 H(+) + L-glutamate Inhibited by 2-fluoroinosine 5'-monophosphate (F-IMP) and by N(2)-hydroxyguanosine 5'-monophosphate (N(2)-OH-GMP). Purine metabolism; GMP biosynthesis; GMP from XMP (L-Gln route): step 1/1. Homodimer. Activated by cAMP receptor protein (CRP). Repressed by DnaA.