Decoding Microbial β-Galactosidases: Structure and Functional Determinants of Mucin Processing

Composed of trillions of microorganisms, the gut microbiome represents a dynamic biochemical ecosystem whose enzymes are central to metabolic pathways and host–microbe interactions. The Gastrointestinal (GI) tract is lined with a protective layer of mucus to aid in maintaining gut homeostasis. One enzyme that influences mucin degradation is β-galactosidases (GAL) which are responsible for cleaving galactose from glycoproteins lining the GI tract. My objective is to use enzyme kinetics to characterize the substrate scope and inhibition of microbial β-galactosidases, advancing fundamental understanding of glycoside hydrolase function within microbial ecosystems. First, I will uncover how these enzymes recognize and process diverse carbohydrates by expanding our lab's current specific activity panel to include an more diverse GALs and more unique substrates. To further probe substrate specificity, I would like to continue structural studies with x-ray crystallography to elucidate what structural basis might be causing these substrate preferences. Next, I aim to identify common compounds that inhibit β-galactosidases to characterize the molecular basis of inhibition. Together, these studies will elucidate the mechanisms governing β-galactosidase substrate specificity and inhibition, providing a structural and functional framework for understanding mucin degradation in the GI tract.