Carbohydrate processing by bacterial pathogens: structural and functional analyses of glycoside hydrolases.




Gregg, Katie Jean

Journal Title

Journal ISSN

Volume Title



Carbohydrates are important in a large number of cellular, physiological, and pathological processes. Carbohydrates often function as the human host’s first line of defence against pathogen invasion by coating surfaces of epithelial cells and as glycan-rich mucins which line the entrances to the body. Various pathogenic bacteria exploit their hosts by modifying their glycans through the production of carbohydrate-active enzymes. Two kinds of pathogenic bacteria that are notable for their production of carbohydrate-active enzymes are Streptococcus pneumoniae and Clostridium perfringens. Both S. pneumoniae and C. perfringens inhabit glycan-rich niches in the human body, the respiratory and gastrointestinal tracts, respectively. To properly colonize their human hosts both bacteria have developed an extensive repertoire of glycoside hydrolases (GHs) which are enzymes responsible for the breakdown of carbohydrates. These GHs have known or predicted specificities for human glycans, specifically those found in mucins. We chose C. perfringens and S. pneumoniae as model systems to study these enzymes due to their large complements of GHs, many of which are known virulence factors. The objectives are to probe the key features of the GHs from these two different kinds of bacteria that inhabit similar human niches and to study catalysis, modularity and overall enzyme structure. This work uses a multidisciplinary approach and provides molecular level insight into the S. pneumoniae and C. perfringens host-pathogen interaction.



Biochemistry, Structural Biology