Seminar will be given by Lindsey Marmont,

This week’s seminar will be given by Lindsey Marmont, Harvard U.

There will be coffee and snacks before the seminar. Please bring your own mug.

Thursday 5 Dec, 4:00PM, HSC 1A5 and on zoom (Passcode: cElegans)

The Achilles’ heel of bacteria: uncovering new antibiotic targets in bacterial cell envelope biogenesis

Peptidoglycan (PG) is a critical component of the bacterial cell envelope. Bacterial cell division is mediated by several proteins that form a complex called the divisome. These proteins are required for the synthesis of PG to cap the new daughter poles. Studies have shown that FtsW and FtsI (FtsWI) together form the essential PG synthase required for this process, however, how PG polymerization by this synthase is regulated is not well understood.

Previous studies have implicated FtsQ, FtsL, and FtsB (FtsQLB) in the regulation of FtsWI , but whether these proteins act directly as positive or negative regulators of the synthase has remained unclear. We purified a five-member Pseudomonas aeruginosa division complex consisting of FtsQLB-FtsWI. The PG polymerase activity of this complex was found to be greatly stimulated relative to the FtsWI synthase alone. Furthermore, support for this activity being important for the cellular function of FtsQLB was provided by the identification of two division-defective variants of FtsL that still form normal FtsQLB-FtsWI complexes but fail to activate PG synthesis, leading to cell filamentation that results from incomplete division septum formation.

Together, these results demonstrate that the conserved FtsQLB complex is a direct activator of PG polymerization by the FtsWI synthase and thereby defines an essential regulatory step in the process of bacterial cell division.