Frontier Leaders: Surprising new functions for peptidoglycan maturation enzymes in bacteria

Frontier Leaders Seminar

Title: Surprising new functions for peptidoglycan maturation enzymes in bacteria

Speaker: Ivo Gomperts Boneca

Affiliation: INSERM, Institut Pasteur

Abstract:

The peptidoglycan is an essential heteropolymer that functions as an exoskeleton that protects bacteria from internal turgor pressure and determines cell shape. This schaffold has to accomodate cell growth and cell division during the cell cycle and its constant remodelling involves the collectif work of synthetases to build new material and hydrolases to generate breaks to allow the insertion of this new material. Because of exoskeletal role in cell physiology, it functions as a barrier for the assembly of macromolecular apparatus at the cell envelop such as flagella or secretion systems. Hence, bacteria have diverted peptidoglycan hydrolases to assist the assembly of these apparatus by generating holes in the peptidoglycan layer. While studying the role of some of these hydrolases in Helicobacter physiology physiology, we stumbled on new surprising functions. We provide evidence for an important role for these enzymes in the maturation of the peptidoglycan by generating motifs for the anchoring of proteins involved in motility. We also provide evidence for a central role of endopeptidases in the transport of DNA during natural transformation across the cell envelop which is both mediated by their enzymatic activity but also by their unexpected binding properties for DNA.