Unraveling glycosyltransferases involved in the biosynthesis of galactose and N-acetylglucosamine-containing glycoconjugates of the protozoan parasite Trypanosoma brucei

• Applicant: Dr. Manuela Damerow
• Subject Area: Parasitology and Biology of Tropical Infectious Disease Pathogens
• Term: from 2013 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 235013941

Trypanosoma brucei is the causative agent of Human African Trypanosomiasis (HAT), also known as 'sleeping sickness', a major health and economic burden in sub-Saharian Africa. As the parasitic disease is always fatal if untreated and therapy relies on a few drugs that present serious limitations, targets for new chemotherapeutic agents are urgently needed. The expression of glycosylphosphatidylinositol-anchored and transmembrane glycoproteins on its cell surface and in its endoyctic and lysosomal system is crucial for survival and infectivity of T. brucei rendering glycosyltransferases (GTs) important potential drug targets. Several glycoprotein glycan structures of the parasite are particularly rich in galactose (Gal) and N-acetylglucosamine (GlcNAc), and the sugar nucleotide donors UDP-Gal as well as UDP-GlcNAc have been shown to be essential. This has prompted the investigation of UDP-Gal- and UDP-GlcNAc-dependent GT genes by database mining of the T. brucei genome and resulted recently in the discovery of a family of twenty-two putative UDP-sugar dependent GTs. The aim of this proposal is to assign representative examples of these putative GTs to specific biochemical functions, to attribute physiological functions, and to identify essential GTs as potential drug targets. This shall be achieved by generation of GT gene knockout or conditional null trypanosome mutants followed by biochemical phenotyping. Using new techniques such as advanced GC- and HPLC mass spectrometry, even minor variations in glycoconjugate structures of GT mutants will be deciphered. Further, to provide unambiguous evidence for respective enzymatic activities, recombinant GTs will be analyzed by radiochemical and mass spectrometric enzyme assays. Finally, protein crystallization trials of novel and essential GT catalytic domains will be initiated in order to obtain information for targeted drug discovery.A comprehensive picture of all glycosylation associated genes in T. brucei will lead to a better understanding of the biosynthesis and processing of parasitic glycoconjugates.

• DFG Programme: Research Fellowships
• International Connection: United Kingdom
• Host: Professor Dr. Mike A J Ferguson