Involved in candicidin biosynthesis (PubMed:11782498). Catalyzes the biosynthesis of 4-amino-4-deoxychorismate (ADC) from chorismate and glutamine (By similarity). chorismate + L-glutamine = 4-amino-4-deoxychorismate + L-glutamate Antibiotic biosynthesis; candicidin biosynthesis. Disruption of the gene abolishes production of candicidin. In the C-terminal section; belongs to the anthranilate synthase component I family.