The transpeptidase PBP2 governs initial localization and activity of the major cell-wall synthesis machinery in E. coli.

Gizem Özbaykal,Mariette Matondo,Andrey Aristov,Sven Van Teeffelen,Francois Simon,Antoine Vigouroux,Eva Wollrab,Thibault Chaze,Baptiste Cordier

doi:10.7554/elife.50629

Gizem Özbaykal, Mariette Matondo + Show 7 more

Open Access

https://doi.org/10.7554/elife.50629

Copy DOI

Abstract

Bacterial shape is physically determined by the peptidoglycan cell wall. The cell-wall-synthesis machinery responsible for rod shape in Escherichia coli is the processive 'Rod complex'. Previously, cytoplasmic MreB filaments were thought to govern formation and localization of Rod complexes based on local cell-envelope curvature. Using single-particle tracking of the transpeptidase and Rod-complex component PBP2, we found that PBP2 binds to a substrate different from MreB. Depletion and localization experiments of other putative Rod-complex components provide evidence that none of those provide the sole rate-limiting substrate for PBP2 binding. Consistently, we found only weak correlations between MreB and envelope curvature in the cylindrical part of cells. Residual correlations do not require curvature-based Rod-complex initiation but can be attributed to persistent rotational motion. We therefore speculate that the local cell-wall architecture provides the cue for Rod-complex initiation, either through direct binding by PBP2 or through an unknown intermediate.

Highlights

The peptidoglycan (PG) cell wall is the major load-bearing structure of the bacterial cell envelope and physically responsible for cell shape (Vollmer et al, 2008)
To study the role of PBP2 for the formation of Rod complexes we characterized its different states of motion, which are potentially representative of different states of substrate binding and activity
New Rod complexes are initiated once PBP2 binds to an immobile substrate in the cell envelope that is different from MreB filaments

Summary

Introduction

The peptidoglycan (PG) cell wall is the major load-bearing structure of the bacterial cell envelope and physically responsible for cell shape (Vollmer et al, 2008). Rod-like cell shape in Escherichia coli requires peptidoglycan synthesis by stable multi-enzyme ’Rod complexes’ containing the transglycosylase RodA, the transpeptidase PBP2, the transmembrane protein RodZ, and the actin homolog MreB (Cho et al, 2016; Emami et al, 2017; Meeske et al, 2016; Morgenstein et al, 2015; Typas et al, 2012).

Objectives

Results

Conclusion