5-phospho-beta-D-ribosylamine + ATP + glycine = ADP + H(+) + N(1)-(5-phospho-beta-D-ribosyl)glycinamide + phosphate Binds 1 Mg(2+) or Mn(2+) ion per subunit. Purine metabolism; IMP biosynthesis via de novo pathway; N(1)-(5-phospho-D-ribosyl)glycinamide from 5-phospho-alpha-D-ribose 1-diphosphate: step 2/2. Monomer. Belongs to the GARS family.