Purification of Bacterial Lipopolysaccharide, and How to Study Its Interactions with Proteins

Lipopolysaccharides (LPS) are an important component of the outer membrane of Gram-negative bacteria. Although LPS is not homogeneous and it varies among bacterial species and even from strain to strain, there are significantly conserved elements that confer and dictate the physicochemical properties of this molecule. Isolating and purifying LPS from its source organism provides the means to investigate the interactions of LPS molecules with other binding partners, such as proteins. Here, we describe methods to isolate LPS and discuss methods for interaction studies.