Involved in triostin biosynthesis. Activates quinoxaline-2-carboxylic acid (QA) via catalysis of the ATP-pyrophosphate exchange reaction dependent on QA, and the formation of the corresponding adenylate. Also activates structural analogs of QA such as quinoline-2-carboxylic acid and thieno[3,2-b]pyridine-5-carboxylic acid, but not quinoline-3-carboxylic acid, quinoline-4-carboxylic acid, pyridine-2-carboxylic acid or 2-pyrazinecarboxylic acid. Optimum pH is 7.0-9.0. Monomer. Belongs to the ATP-dependent AMP-binding enzyme family.