An Activity-Based Probe for Studying Crosslinking in Live Bacteria

Samir Gautam, Taehan Kim, Takuji Shoda, Sounok Sen, Deeksha Deep, Ragini Luthra, Maria Teresa Ferreira, Mariana Luisa Pinho, David A. Spiegel

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Penicillin-binding proteins (PBPs) catalyze the crosslinking of peptidoglycan (PG), an essential process for bacterial growth and survival, and a common antibiotic target. Yet, despite its importance, little is known about the spatiotemporal aspects of crosslinking - largely because of a lack of experimental tools for studying the reaction in live bacteria. Here we introduce such a tool: an activity-based probe that enables visualization and relative quantitation of crosslinking in vivo. In Staphylococcus aureus, we show that fluorescent mimics of the natural substrate of PBPs (PG stem peptide) are covalently incorporated into the cell wall, installing fluorophores in place of natural crosslinks. These fluorescent stem peptide mimics (FSPMs) are selectively recognized by a single PBP in S. aureus: PBP4. Thus, we were able to use FSPM pulse-labeling to localize PBP4 activity in live cells, showing that it is recruited to the septum in a manner dependent on wall teichoic acid.

Original languageEnglish
Pages (from-to)10492-10496
Number of pages5
JournalAngewandte Chemie-International Edition
Issue number36
Publication statusPublished - 1 Sep 2015


  • bacteria
  • biosensors
  • crosslinking
  • fluorescent probes
  • peptidoglycans


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