Figure 6

Affinity imaging of antibiotic binding sites. (a) Phase contrast and (b) fluorescence image of Lactococcus lactis cells during the course of the division process. Fluorescent vancomycin accumulates at the division site, by attaching specifically to d-Ala-d-Ala sites of cell wall peptidoglycan. (c) AFM image of a cell showing a well-defined division septum as well as a ring-like structure expected to be rich in nascent peptidoglycan (white box). (d) Adhesion force map (gray scale: 100 pN) recorded with a vancomycin tip on the septum region (highlighted by the white box in (c)). Adhesion events are essentially located in the septum region (red line), more specifically on the ring-like structure, suggesting that newly formed peptidoglycan is inserted. Reprinted with permission from ref. [53]