Fine tuning of the active site modulates specificity in the interaction of O-acetylserine sulfhydrylase isozymes with serine acetyltransferase

► Changes in active sites of OASS isozymes modulate pentapeptides recognition. ► Pentapeptide affinities depends on P3-P4-P5 for strength and P1-P2 for specificity. ► Selective OASS inhibitors, potentially antibiotic agents, might be developed.