Shedding Light on Bacterial Physiology with Click Chemistry

Abstract

Bacteria constitute a major lifeform on this planet and play numerous roles in ecology, physiology, and human disease. However, conventional methods to probe their activities are limited in their ability to visualize and identify their functions in these diverse settings. In the last two decades, the application of click chemistry to label these microbes has deepened our understanding of bacterial physiology. With the development of a plethora of chemical tools that target many biological molecules, it is possible to track these microorganisms in real-time and at unprecedented resolution. Here, we review click chemistry, including bioorthogonal reactions, and their applications in imaging bacterial glycans, lipids, proteins, and nucleic acids using chemical reporters. We also highlight significant advances that have enabled biological discoveries that have heretofore remained elusive.

Keywords: Bacteria; Bioorthogonal chemistry; Click chemistry; Fluorescent probes; Imaging.

Figure 1.

Chemical reporter strategy to image biological molecules within bacteria using click chemistry.

Figure 2.

Click reactions used to label biological molecules.

Figure 3.

Chemical reporters to target glycans within bacteria. (a) Chemical probes. (b) Fluorogenic probe (QTF) to detect mycolyltransferase, Ag85, activity in mycobacteria.

Figure 4.

Chemical reporters to target lipids within bacteria.

Figure 5.

Chemical strategies to image proteins within bacteria. (a) Bioorthogonal Non-Canonical Amino Acid Tagging (BONCAT) with noncanonical amino acids (shown) and (b) site-specific ncAA incorporation (e.g., amber suppression method).

Figure 6.

Chemical reporters to target D-amino acids within bacteria.