title: New Insights into Nisin's Antibacterial Mechanism Revealed by Binding Studies with Synthetic Lipid II Analogues.
abstract: Nisin is the preeminent lantibiotic, and to date its antibacterial mechanism has been investigated using a variety of techniques. While nisin's lipid II-mediated mode of action is well-established, a detailed analysis of the thermodynamic parameters governing this interaction has not been previously reported. We here describe an approach employing isothermal titration calorimetry to directly measure the affinity of nisin for lipid II and a number of synthetic lipid II precursors and analogues. Our measurements confirm the pyrophosphate unit of lipid II as the primary site of nisin binding and also indicate that the complete MurNAc moiety is required for a high-affinity interaction. Additionally, we find that while the pentapeptide unit of the lipid II molecule is not required for strong binding by nisin, it does play an important role in stabilizing the subsequently formed nisin-lipid II pore complex, albeit at an entropic cost. The anchoring of lipid II in a membrane environment was also found to play a significant role in enhancing nisin binding and is required in order to achieve a high-affinity interaction.
authors.affiliation: Department of Medicinal Chemistry & Chemical Biology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University , Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
authors.forename: Peter
authors.initials: P
authors.lastname: 't Hart
authors.affiliation: Membrane Biochemistry and Biophysics Group, Department of Chemistry, Utrecht University , Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: Sabine F
authors.initials: SF
authors.lastname: Oppedijk
authors.affiliation: Membrane Biochemistry and Biophysics Group, Department of Chemistry, Utrecht University , Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: Eefjan
authors.initials: E
authors.lastname: Breukink
authors.affiliation: Department of Medicinal Chemistry & Chemical Biology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University , Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
authors.forename: Nathaniel I
authors.initials: NI
authors.lastname: Martin
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D001419:Bacteria / Q000378:metabolism*; D013294:Lactococcus lactis / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D009561:Nisin / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D014538:Uridine Diphosphate N-Acetylmuramic Acid / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D014538:Uridine Diphosphate N-Acetylmuramic Acid; C069249:muramyl-NAc-(pentapeptide)pyrophosphoryl-undecaprenol; D009561:Nisin