Grant: Discovery Grants Program - Individual

Bacteria produce many sugars that they display on their surface and that are called collectively their glycome. The bacterial glycome shows extreme diversity by the nature of macromolecules that comprise these sugars and the wide variety of highly modified sugars that are incorporated. Bacterial genomes (i.e. their DNA) provide an enormous reservoir of enzymes with potentially new activities for the synthesis and assembly of these sugars in complex structures called glycans. Unraveling these activities and determining how the enzymes function is of fundamental significance. Our NSERC research program deals with generating fundamental knowledge in bacterial glycobiology, using the bacterium Campylobacter jejuni as a model since it harbors several sugar synthesis and utilization pathways. We have pioneered the characterization of many enzymes from various C. jejuni pathways. These include pathways that add sugars onto proteins and pathways that assemble the capsule, a large glycan structure that surrounds the bacterium and provides defenses against clearance by hosts or against deleterious environmental conditions. Our long-term goal is to characterize additional enzymes involved in the synthesis and assembly of the capsule of C. jejuni. We are now able to produce very unusual 7-carbon sugars that serve as building blocks for capsule assembly, which now allows us to study the capsular assembly. For this, we will study a new class of enzymes that can connect sugars together (sugar transferases) and others that further modify the sugars by adding methyl groups (methyl transferases). We will also characterize a novel capsule synthesis regulator that we identified through our prior work and will explore potential interactions between the enzymes involved in capsule synthesis. This work will contribute to training 1 PhD student, 2 MSc student, 9 undergraduate students and a part-time technician in bacteriology and glycobiology (study of sugars form synthesis to function), gaining skills transferable in biotechnology and industry. The work will enhance our knowledge in glycobiology and on capsule synthesis in C. jejuni, thus qualifying as Natural Sciences and Engineering contributions. Our objectives will contribute novel methodological and conceptual developments. For example, characterizing the sugar transferases will extend the glycobiology toolbox and will unlock their combinatorial power for the assembly of complex glycans of desired structure or functionality that are often very difficult to synthesize by chemical methods and that could have medical or industrial applications. Characterizing enzyme interactions may be applied in industry to enhance efficacy of enzymatic reactions. We are confident that we can make significant contributions to the field and even lead this field, as indicated by the now strong uptake of our work by other glycobiologists.