Understanding the Integrity of Gram negative Bacterial Membranes in the Extracellular Space in Leaves.

The extracellular space in leaves is a battleground for plant-pathogen interactions. Studies on a metal hyperaccumulator plant N. caerulescens and the plant pathogen P. syringae, we observed that zinc conferred protection against infection, although the molecular mechanism for this is not understood. The cation-binding ability of lipopolysaccharides is one of the key determinants of bacterial outer membrane (OM) permeability and Mg2+ plays an important role in OM stability. We hypothesize that hyperaccumlated metals confer protection to plants by binding to the cation binding sites on the outer membrane causing disruption. Using floating models of the Gram negative bacterial outer membrane we aim to model this effect, examining the structure of the model membranes in the presence of Mg2+ and Zn2+ and the competition between these two cations for the membrane binding sites.