By Chardelle Prevatt
Polysaccharides, or polymers that consist of a chain of sugar residues, are commonly used by pathogenic bacteria to counter host defences. By coating the bacterial surface in a protective layer, polysaccharides play vital roles in mediating host-pathogen interactions. Polysaccharide production is an energy expensive process. Bacteria have evolved quality control mechanisms in order to cover their surfaces with polymers whose chain lengths fall within a size range that is appropriate for function. This may limit energy “wasted” in producing polysaccharide chains that are longer than necessary.
In a paper, published in the Proceedings of the National Academy of Sciences, GlycoNet researchers—Drs. Chris Whitfield, Todd Lowary, Matthew Kimber, Iain Mainprize, Olga Ovchinnikova—and their colleagues Danielle Williams and Dr. Akihiko Koizumi outline one of the fundamental processes by which bacteria determine the composition and chain length of polysaccharides. The researchers describe a family of proteins found in pathogens including Klebsiella pneumoniae, Aeromonas hydrophila, and Serratia marcescens that are sufficient for both polymerization and chain termination. These proteins possess a ‘molecular ruler’ structure to dictate the length of the polymer chains.
“We have revealed new insights into the cellular processes of bacteria and the mechanisms that bacteria use to outwit host immune defences,” said Dr. Whitfield. “Understanding these processes could potentially allow scientists to develop new strategies for glycoengineering, where polymers of defined structure and chain length are produced for therapeutic or industrial applications.”
Dr. Lowary added, “In the midst of growing concerns over antimicrobial resistance, these findings can possibly help target bacteria, by-pass their defences, and improve antibiotic and vaccine development for a number of bacterial infections.”
To view the full research paper, click here.