Catalyzes the attachment of the cognate amino acid to the corresponding tRNA in a two-step reaction: the amino acid is first activated by ATP to form a covalent intermediate with AMP and is then transferred to the acceptor end of the cognate tRNA. ATP + L-glutamate + tRNA(Glu) = AMP + diphosphate + L-glutamyl-tRNA(Glu) ATP + L-proline + tRNA(Pro) = AMP + diphosphate + L-prolyl-tRNA(Pro) Component of the multisynthetase complex which is comprised of a bifunctional glutamyl-prolyl-tRNA synthetase, the monospecific isoleucyl, leucyl, glutaminyl, methionyl, lysyl, arginyl, and aspartyl-tRNA synthetases as well as three auxiliary proteins, p18, p48 and p43. In the N-terminal section; belongs to the class-I aminoacyl-tRNA synthetase family. Glutamate--tRNA ligase type 2 subfamily. In the C-terminal section; belongs to the class-II aminoacyl-tRNA synthetase family.