Discovery of a Diverse Set of Bacteria That Build Their Cell Walls without the Canonical Peptidoglycan Polymerase aPBP
Sharanjeet Atwal, Suthida Chuenklin, Edward M. Bonder, Juan Flores, Joseph J. Gillespie, Timothy Driscoll, Jeanne Salje
Abstract
Peptidoglycan (PG) is a large, cross-linked polymer that forms the cell wall of most bacterial species and confers shape, rigidity, and protection from osmotic shock. It is also a potent stimulator of the immune response in animals. PG is normally polymerized by two groups of enzymes, aPBPs and bPBPs working together with shape, elongation, division, and sporulation (SEDS) proteins. We have identified a diverse set of host-associated bacteria that have selectively lost aPBP genes while retaining bPBP/SEDS and show that some of these build a minimal PG-like structure. It is expected that these minimal cell walls built in the absence of aPBPs improve the evolutionary fitness of host-associated bacteria, potentially through evasion of PG-recognition by the host immune system.