Structural properties of the outer membrane of Gram-negative bacteria

The cell wall of Gram-negative bacteria plays a crucial role in the bacteria resistance to certain antimicrobials and its adaptation to the host environment. The first line of cell defense is its outer membrane composed of glycerophos-pholipids in the inner monolayer, lipopolysaccharides (LPS) in the outer monolayer and integral proteins. To understand the details of the outer membrane structure we build a molecular model of the Ra-LPS/LPS bilayer containing 8 β-barrels of the OmpA protein. We pay particular attention to the structural evolution of the outermost part of the LPS molecules (O-antigen) and analyze its conformational behavior using different computational criteria.