Rie Nygaard, Chris L. B. Graham, Meagan Belcher Dufrisne, Jonathan D. Colburn, Joseph Pepe, Molly A. Hydorn, Silvia Corradi, Chelsea M. Brown, Khuram U. Ashraf, Owen N. Vickery, Nicholas S. Briggs, John J. Deering, Brian Kloss, Bruno Botta, Oliver B. Clarke, Linda Columbus, Jonathan Dworkin, Phillip J. Stansfeld, David I. Roper & Filippo Mancia

Peptidoglycan (PG) assembly requires a glycosyltransferase (GT) to generate a glycan polymer using a Lipid II substrate, which is then crosslinked to the existing PG via a transpeptidase (TP) reaction. A Shape, Elongation, Division and Sporulation (SEDS) GT enzyme and a Class B Penicillin Binding Protein (PBP) form the core of the multi-protein complex required for PG assembly. Here we used single particle cryo-electron microscopy to determine the structure of a cell elongation-specific E. coli RodA-PBP2 complex. We combine this information with biochemical, genetic, spectroscopic, and computational analyses to identify the Lipid II binding sites and propose a mechanism for Lipid II polymerization. Our data suggest a hypothesis for the movement of the glycan strand from the Lipid II polymerization site of RodA towards the TP site of PBP2, functionally linking these two central enzymatic activities required for cell wall peptidoglycan biosynthesis.

Nature Communications. August 2023