The outer membrane (OM) of Gram-Negative bacteria (GNB) is an asymmetric structure which contains complex lipids known as lipopolysaccharides (LPSs) on the outer surface. LPSs comprise the membrane anchoring Lipid-A, the anionic core oligosaccharides and the very large, solution facing O-antigen which acts as a hydrophilic barrier to antibiotics. We have recently achieved an accurate model of the outer membrane using short chain LPS and now wish to start examining its interaction with antimicrobial peptides and proteins. These will include the antibiotic polymyxin, human innate immune peptide cathelicidin, LPS specific bacteriocin, colicin N and a beta defensin.