Structure and function of invertebrate Golgi hexosaminidases

β-Hexosaminidases (β-N-acetylglucosaminidases and β-N-acetylgalactosaminidases; EC 3.2.1.52) are ubiquituous enzymes with multiple roles in glycoconjugate metabolism and remove terminal β-N-acetylhexosamine residues from glycan, glycolipid, glycoprotein and glycosaminoglycan substrates; whereas these enzymes are catabolic in mammals, in non-vertebrate species they are often mediating purposeful processing steps during the maturation of N-linked oligosaccharides (analogous to ER and Golgi mannosidases). However, the biological significance of, and the structural basis for, these hexosaminidase-mediated glycan-processing reactions in non-vertebrates are poorly understood. In the proposal project, the aim is to understand the substrate specificity of nematode and insect hexosaminidases in terms of the residues involved in catalysis and explore whether deletion of nematode hexosaminidase genes has an effect on nematode responses to stress and infection.