ACS Chem. Biol. https://doi.org/10.1021/acschembio.8b00559 (2018)

Gram-positive bacteria such as Streptococcus pneumoniae are surrounded by a cell wall containing a thick peptidoglycan (PG) layer that is covalently modified with linear polysaccharides such as teichoic acids (TA). Targeting cell wall assembly is a common approach for treating Gram-positive infections, though the ability to interfere specifically with TA metabolism is in a nascent stage. Efforts to do so require better knowledge and, therefore, probes capable of monitoring TA metabolism in the context of PG assembly. Unlike TA assembly, PG assembly can be monitored by incorporating fluorescent amino acids into the growing PG. To monitor TA assembly, Bonnet et al. added an azido group to choline, which they found could uniformly label the S. pneumoniae surface when a ‘clickable’ fluorescent probe was introduced to the cells along with the azido-choline. Their two-step, one-pot approach enabled pulse-chase experiments, simultaneously monitoring PG and TA assembly, as well as the determination of localization and timing of TA insertion with respect to the cell cycle and PG assembly. On the basis of these experiments, the authors concluded that TA and PG assembly are largely coincident but TA incorporation persists at the division site later than PG assembly.

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Claire Durmont