The best screening hit in this study was nocardamine (Vina score -12.2 kcal/mole), a siderophore first isolated as its ferric complex (known as ferrioxamine Ε ). It is a macrocycle fitting exactly the channel opening at the N terminus (Fig. ). However, being a siderophore means binding Fe 3+ ions with extremely high affinity (K d in the order of 10 -30 M ). For practical purposes, this implies that in the cells these molecules will exist exclusively as their complexes, sequestering iron and other metals from the bodily liquids. It is prescribed specifically for this purpose -to remove excess of iron or aluminium from the body (e.g. to treat metal poisoning). In the screening it did demonstrate an unremarkable score of -5.3 kcal/mole. It was apparent that both compounds in physiological conditions will exist as metal complexes. Since the complexes shall have different geometry and chain flexibility, we have conducted a docking study on ferric complexes of both siderophores.