Background:The mechanism of action of the potent antibiotic empedopeptin was not known. Results: Empedopeptin forms calcium-dependent complexes with peptidoglycan precursors, particularly lipid II. Conclusion: Bacterial cell wall synthesis is blocked by sequestration of the bactoprenol carrier. Significance: This mechanism is proposed for a wider class of structurally related antibiotics including empedopeptin, tripropeptins, and plusbacins.