Converts chorismate to 2-amino-4-deoxychorismate (ADIC). Involved in the biosynthesis of the benzoxazolinate moiety of the enediyne antitumor antibiotic C-1027. (2S)-2-amino-4-deoxychorismate + L-glutamate = chorismate + L-glutamine Belongs to the anthranilate synthase component I family.