An Alternative and Conserved Cell Wall Enzyme That Can Substitute for the Lipid II Synthase MurG
Lvxia Zhang, Karina Ramijan, Víctor J. Carrión, Lizah T. van der Aart, Joost Willemse, Gilles P. van Wezel, Dennis Claessen
Abstract
Almost all bacteria are surrounded by a cell wall, which protects cells from environmental harm. Formation of the cell wall requires the precursor molecule lipid II, which in bacteria is universally synthesized by the conserved and essential lipid II synthase MurG. We here exploit the unique ability of an actinobacterial strain capable of growing with or without its cell wall to discover an alternative lipid II synthase, MglA. Although this enzyme bears only weak sequence similarity to MurG, it can functionally replace MurG and can even do so in organisms that naturally have only a canonical MurG. The observation that MglA proteins are found in many actinobacteria highlights the plasticity in cell wall synthesis in these bacteria and demonstrates that important new cell wall biosynthetic enzymes remain to be discovered.