Required for the assimilation of symbiotically fixed nitrogen into amino acids in root nodules. 2 L-glutamate + NAD(+) = 2-oxoglutarate + H(+) + L-glutamine + NADH Binds 1 [3Fe-4S] cluster. Inhibited by malate, citrate, glutamate, NAD(+) and azaserine, but not by 2-2' dipyridil and N-ethylmaleimide. Optimum pH is 7.5-8.5. Amino-acid biosynthesis; L-glutamate biosynthesis via GLT pathway; L-glutamate from 2-oxoglutarate and L-glutamine (NAD(+) route): step 1/1. Energy metabolism; nitrogen metabolism. Monomer. Expressed in infected cells in root nodules. Barely detected in roots and stems. Up-regulated during nodule development. Belongs to the glutamate synthase family.