Biology subjects

Sterckx, Y. G.

Publications and source records attributed to Sterckx, Y. G..

2 recordsLinked to original sources

bioRxiv2025

Structural basis for the inhibition of Trypanosoma brucei enolase by a camelid single-domain antibody

Trypanosoma brucei is an extracellular protozoan that causes neglected tropical diseases in both humans and livestock. The parasite has a bipartite life cycle involving an insect vector and a mammalian host. Within the latter, it mainly thrives as a blood-borne parasite that relies on glycolysis to support its energy metabolism. It is for this reason that trypanosomal glycolytic enzymes have been investigated as potential targets for the development of trypanosome-killing drugs. Recent work from our lab has shown that they are also interesting biomarkers for the detection of active trypanosome infections. T. brucei enolase (TbrENO) is a trypanosomal glycolytic enzyme that has gathered interest in both drug and diagnostics development. In this paper, we report the discovery of a camelid single domain antibody (sdAb aka nanobody) that specifically recognises and inhibits TbrENO. The sdAbs inhibitory mechanism is unraveled through a combination of protein biochemistry, biophysics, and structural biology. Author summaryTrypanosoma brucei is a unicellular parasite that lives in the bloodstream of humans and animals, where it causes serious but often overlooked diseases. Because it depends heavily on breaking down glucose to produce energy, the parasites glucose-processing proteins (called glycolytic enzymes) have become important targets for both new treatments and improved diagnostic tools. One of these proteins, called T. brucei enolase (TbrENO), has recently drawn attention for its potential in drug development and disease detection. In this study, we discovered a special type of antibody, known as a camelid single-domain antibody (sdAb aka nanobody), that can specifically recognize and block the activity of TbrENO. We employed a combination of various laboratory techniques to understand exactly how the sdAb binds to and inhibits the enzyme. Our findings provide new insight into how TbrENO can be inhibited in a way that does not require active site binding and highlight the value of sdAbs as precise tools for targeting key parasite proteins.

bioengineering↗

bioRxiv2025

The major diagnostic VSG LiTat 1.3 of the human parasite Trypanosoma brucei gambiense is a trimer in solution

Human African trypanosomiasis (HAT) remains a significant health burden in sub-Saharan Africa, with serological diagnosis relying heavily on parasite variant surface glycoproteins (VSGs). In this study, we present evidence that LiTat 1.3 (a key VSG in the diagnosis of T. b. gambiense infections) displays a homotrimeric architecture in solution instead of the archetypal homodimeric structure expected for a VSG. This was demonstrated by adopting an integrative structural biology approach encompassing AlphaFold-based structure prediction, analytical gel filtration (AGF), size exclusion chromatography with multi-angle light scattering (SEC-MALS), and small-angle X-ray scattering (SAXS). Furthermore, the SAXS data demonstrate that the C-terminal domains of trimeric VSGs exhibit the same degree of flexibility as observed in dimeric VSGs. Hence, the biophysical characterization of LiTat 1.3 VSG adds to the limited, yet growing body of knowledge that certain VSG classes occur as homotrimers instead of homodimers. Authors SummaryHuman African trypanosomiasis (HAT) is caused by Trypanosoma brucei gambiense, a parasite transmitted by tsetse flies. To survive in the human host, these parasites cover themselves with a coat consisting of millions of identical copies of surface proteins called variant surface glycoproteins (VSGs). This VSG coat is regularly switched by the parasite to escape the immune system. Some of these VSGs, including one known as LiTat 1.3, are used in diagnostic tests to detect potentially infected patients. In our study, we discovered that, unlike most VSGs that form pairs of identical molecules (homodimers), LiTat 1.3 assembles into groups of three (homotrimers). Using structural and biophysical techniques, we showed that this trimeric form is stable in solution and retains the dynamic behavior observed in dimeric VSGs. Understanding how such structural variations arise and how they influence immune recognition may help explain why certain VSGs, like LiTat 1.3, are particularly effective in diagnosis and could ultimately guide the development of improved tools to monitor and control sleeping sickness.

microbiology↗