Physicochemical properties of microbial glycopolymers

Publisher Summary Glycolipids are essential constituents of cellular membranes with a high number of functions. They may act as receptors, be important for cell aggregation and dissociation, and may be responsible for specific cellular contact and for signal transduction. There are large varieties of glycolipids also in bacterial species, and it can be assumed that only a small part of this variety is known up to now. This chapter focuses on the description of the physicochemical characteristics of essentially three groups of bacterial glycolipids: lipopolysaccharides (LPSs), rhamnolipids, and mycobacterial glycolipids. The functional role of glycolipids, such as lipopolysaccharides, polysaccharides or other glycoconjugates in membranes like the outer membrane of Gram-negative bacteria, arises from these glycopolymers acting as the first point of interaction of the bacterial cells with cells of the host's immune system. Therefore, their physical states, such as the fluidity of their acyl chains and the conformation of the backbones, are essential determinants of bacterial defense against the attack mounted by components of the human immune system, such as complement and antimicrobial proteins. The action of bacterial glycopolymers with molecules and cells of the human immune system, which eventually may lead to pathophysiological effects like septic shock, is exerted by isolated polymers after their release from the bacteria.