Mario Waespy
University of Bremen, Germany
Title: Insight into structure and function relation of trans-sialidase from Trypanosoma congolense
Biography
Biography: Mario Waespy
Abstract
Trypanosomes are protozoan parasites causing trypanosomiasis in Latin America (Chagas' disease) and Sub-Sahara Africa (sleeping sickness in humans and Nagana in livestock). African Animal Trypanosomiasis (AAT or Nagana), caused by Trypanosoma congolense is a devastating disease in domestic and wild African animals causing an annual loss in agriculture productivity of about 4.5 billion USD due to the death of more then 3 million cattle, whereas 40 millions are estimated to be threatened. Trypanosomes express unusual enzymes termed trans-sialidase (TS). TS are surface-bound enzymes, which catalyse the transfer of sialic acids (Sia) from host cell glycoconjugates to terminal galactose residues on acceptor substrates of the parasite’s surface. Since trypanosomes are unable to synthesise Sia de novo they employ TS to cover their surface with Sia to resist and even manipulate host’s innate and acquired immune system and consequently extend their survival in the different hosts. Several studies have shown that TS play important roles in the pathology of trypanosomiasis in mammalian host and are essential for survival of the parasite also in the insect vector, representing TS as a major virulence factor. Our studies on Trypanosoma congolense TS, revealed 14 active variants exhibiting significantly different enzymatic activities, although these can not be sufficiently explained by amino acid variations at the catalytic centre. Besides the catalytic domain (CD), all TS contain a lectin-like domain (LD), whose biological function still remains unknown. Structural and functional characterisation of Trypansoma congolense TS-LD provided new insight into enzymatic activities and correlated biological functions.