Figure 1: A) Architecture of LPSs in Gram negative bacteria. LPSs contain three main regions: the O-polysaccharide (that consists of n tetrasaccharide repeat units) and the outer core oligosaccharide. The outer core polysaccharide is linked to a core oligosaccharide and lipid A. B) Detection of lysozyme-LPS interaction and complex formation by double staining with imidazole-zinc/Coomassie brilliant blue R-250 [37]. C) Schematic representation of slab PAGE-mass spectrometry [56,57]. This technology allows assigning molecular structures to the LPS species recovered from PAGE gels by high-efficiency passive elution [60].