Catalyzes the conversion of L-glutamine and 2-oxoglutarate into two molecules of L-glutamate. 2 L-glutamate + NADP(+) = 2-oxoglutarate + H(+) + L-glutamine + NADPH Binds 1 [4Fe-4S] cluster. Amino-acid biosynthesis; L-glutamate biosynthesis via GLT pathway; L-glutamate from 2-oxoglutarate and L-glutamine (NADP(+) route): step 1/1. Energy metabolism; nitrogen metabolism. Up-regulated at high salt concentration.