Transport and polymerisation of bacterial polysaccharides: from cytoplasm to the outside world

Professor Naismith wishes to understand the transport and polymerisation of bacterial polysaccharides, the process by which sugar molecules synthesised within the cell cytoplasm are transported across the cytoplasmic membrane, polymerised and attached to the protein substrates. The first step of the process is coupling of sugar to a lipid carrier by two broad classes of integral membrane proteins that carry out this process. Professor Naismith’s group plans a study of the structures and mechanisms of action of these classes. The next step is flipping across the cytoplasm, carried out by the flippase protein, after which the units are polymerised into a defined length by a polymerase. While the polymer can be attached to a protein or exported or transferred to another receptor, the group will focus research on the attachment of the polymer to protein substrates. Extracellular polysaccharides play a variety of roles in bacteria, especially their role in bacterial pathogenesis. The sugar polymers can help evade the immune system, protect against the immune response or even modulate the immune system.