Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States.
Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, Massachusetts 02115, United States.
ACS Chem Biol. 2020 May 15;15(5):1222-1231. doi: 10.1021/acschembio.9b00908. Epub 2020 Feb 26.
This report describes the first synthesis and application of a fluorescent teixobactin analogue that exhibits antibiotic activity and binds to the cell walls of Gram-positive bacteria. The teixobactin analogue, Lys(Rhod),Arg-teixobactin, has a fluorescent tag at position 9 and an arginine in place of the natural -enduracididine residue at position 10. The fluorescent teixobactin analogue retains partial antibiotic activity, with minimum inhibitory concentrations of 4-8 μg/mL across a panel of Gram-positive bacteria, as compared to 1-4 μg/mL for the unlabeled Arg-teixobactin analogue. Lys(Rhod),Arg-teixobactin is prepared by a regioselective labeling strategy that labels Lys with an amine-reactive rhodamine fluorophore during solid-phase peptide synthesis, with the resulting conjugate tolerating subsequent solid-phase peptide synthesis reactions. Treatment of Gram-positive bacteria with Lys(Rhod),Arg-teixobactin results in septal and lateral staining, which is consistent with an antibiotic targeting cell wall precursors. Concurrent treatment of Lys(Rhod),Arg-teixobactin and BODIPY FL vancomycin results in septal colocalization, providing further evidence that Lys(Rhod),Arg-teixobactin binds to cell wall precursors. Controls with either Gram-negative bacteria, or an inactive fluorescent homologue with Gram-positive bacteria, showed little or no staining in fluorescence micrographic studies. Lys(Rhod),Arg-teixobactin can thus serve as a functional probe to study Gram-positive bacteria and their interactions with teixobactin.
本报告描述了首例荧光泰妙菌素类似物的合成及其应用，该类似物具有抗生素活性并与革兰氏阳性菌的细胞壁结合。该泰妙菌素类似物，Lys（Rhod），Arg-泰妙菌素，在 9 位具有荧光标记，在 10 位取代了天然的 -内酰脲残基。荧光泰妙菌素类似物保留了部分抗生素活性，与未标记的 Arg-泰妙菌素类似物相比，对一组革兰氏阳性菌的最小抑菌浓度为 4-8μg/mL，而 1-4μg/mL。Lys（Rhod），Arg-泰妙菌素是通过一种区域选择性标记策略制备的，该策略在固相肽合成过程中用反应性胺的罗丹明荧光团标记 Lys，得到的缀合物耐受随后的固相肽合成反应。用 Lys（Rhod），Arg-泰妙菌素处理革兰氏阳性菌会导致隔膜和侧染色，这与靶向细胞壁前体的抗生素一致。Lys（Rhod），Arg-泰妙菌素与 BODIPY FL 万古霉素同时处理会导致隔膜共定位，进一步证明 Lys（Rhod），Arg-泰妙菌素与细胞壁前体结合。用革兰氏阴性菌或与革兰氏阳性菌的无活性荧光类似物作为对照，在荧光显微镜研究中几乎没有或没有染色。因此，Lys（Rhod），Arg-泰妙菌素可以作为研究革兰氏阳性菌及其与泰妙菌素相互作用的功能探针。
