N-glycosylation modulates enzymatic activity of Trypanosoma congolense trans-sialidase
Jana Rosenau, Isabell Louise Grothaus, Yikun Yang, Nilima Dinesh Kumar, Lucio Colombi Ciacchi, Sørge Kelm, Mario Waespy
Abstract
treatment of TconTS1 led to a decrease in substrate affinity relative to the untreated enzyme but had no impact on the conversion rate. Furthermore, we observed no changes in secondary structure elements of hypoglycosylated TconTS1 in CD experiments. Finally, our molecular dynamics simulations provided evidence for interactions between monosaccharide units of the highly flexible N-glycans and some conserved amino acids located at the catalytic site. These interactions led to conformational changes, possibly enhancing substrate accessibility and enzyme-substrate complex stability. The here-observed modulation of catalytic activity via N-glycans represents a so-far-unknown structure-function relationship potentially inherent in several members of the TS enzyme family.