Medicinal Chemistry and Chemical Biology, Utrecht Institute for Pharmaceutical Sciences, Department of Pharmaceutical Sciences, Faculty of Science, Utrecht University , P.O. Box 80082, 3508 TB Utrecht, The Netherlands.
Bioconjug Chem. 2013 Dec 18;24(12):2058-66. doi: 10.1021/bc400401k. Epub 2013 Dec 5.
Functionalization of the lantibiotic nisin with fluorescent reporter molecules is highly important for the understanding of its mode of action as a potent antimicrobial peptide. In addition to this, multimerization of nisin to obtain multivalent peptide constructs and conjugation of nisin to bioactive molecules or grafting it on surfaces can be attractive methods for interference with bacterial growth. Here, we report a convenient method for the synthesis of such nisin conjugates and show that these nisin derivatives retain both their antimicrobial activity and their membrane permeabilizing properties. The synthesis is based on the Cu(I)-catalyzed alkyne-azide cycloaddition reaction (CuAAC) as a bioorthogonal ligation method for large and unprotected peptides in which nisin was C-terminally modified with propargylamine and subsequently efficiently conjugated to a series of functionalized azides. Two fluorescently labeled nisin conjugates together with a dimeric nisin construct were prepared while membrane insertion as well as antimicrobial activity were unaffected by these modifications. This study shows that C-terminal modification of nisin does not deteriorate biological activity in sharp contrast to N-terminal modification and therefore C-terminally modified nisin analogues are valuable tools to study the antibacterial mode of action of nisin. Furthermore, the ability to use stoichiometric amounts of the azide containing molecule opens up possibilities for surface tethering and more complex multivalent structures.
将荧光报告分子功能化到类细菌素乳链菌肽（nisin）上对于理解其作为一种有效的抗菌肽的作用模式非常重要。此外，将乳链菌肽多聚化以获得多价肽构建体，将乳链菌肽与生物活性分子缀合或将其接枝到表面上，可能是干扰细菌生长的有吸引力的方法。在这里，我们报告了一种方便的合成此类乳链菌肽缀合物的方法，并表明这些乳链菌肽衍生物保留了它们的抗菌活性和膜通透性。该合成基于铜（I）催化的炔烃-叠氮化物环加成反应（CuAAC）作为生物正交的连接方法，用于大的未保护肽，其中乳链菌肽在 C 端用丙炔胺修饰，随后有效地与一系列功能化的叠氮化物缀合。制备了两种荧光标记的乳链菌肽缀合物以及二聚体乳链菌肽构建体，而这些修饰对膜插入和抗菌活性没有影响。这项研究表明，与 N 端修饰相反，乳链菌肽的 C 端修饰不会降低生物活性，因此 C 端修饰的乳链菌肽类似物是研究乳链菌肽抗菌作用模式的有价值的工具。此外，使用含叠氮化物的分子的化学计量量的能力为表面固定化和更复杂的多价结构开辟了可能性。
