Cell wall formation. Catalyzes the addition of L-glutamate to the nucleotide precursor UDP-N-acetylmuramoyl-L-alanine. ATP + L-glutamate + UDP-N-acetyl-alpha-D-muramoyl-L-alanine = ADP + H(+) + phosphate + UDP-N-acetyl-alpha-D-muramoyl-L-alanyl-L-glutamate Cell wall biogenesis; peptidoglycan biosynthesis. Belongs to the MurCDEF family. MurD2 subfamily.