You are hereJan Steyaert, Executive Director
Jan Steyaert, Executive Director
Enzyme mechanisms and Biomedical targets
For many years, Ribonucleases, N-ribohydrolases and thiamine-dependent decarboxylases have been our model systems of choice to study enzyme catalysis. Over the years, we coupled older physicochemical techniques (LFR, isotope exchange effects, steady state and fast kinetics) to modern protein engineering approaches to study the chemistry of the enzyme catalysed reaction in all its details. Current research topics include DHFR and tRNA editing enzymes. In a more applied project, we are validating gated nanocontainers filled with enzymes as nanoreactors to activate particular compounds ‘in situ’. To deliver these nanocontainers to particular cells, specific camel single-domain antibodies (nanobodies) will be fused to these particles by chemical or biochemical means.
Currently, we are expanding our research in structural biology towards biomedical targets. In the early stages of structural genomics, challenging targets such as those that are poorly soluble, unstable, intrinsically (partially) unstructured or are highly flexible are put aside because they do not crystallize. One way out is to purify and crystallize these proteins in complex with other proteins that reduce flexibility or improve the solubility of these 'higher hanging fruits'. The occurrence of bona fide antibodies devoid of light chains in Camelidae was one of the major discoveries within our department. Last years, we have shown that nanobodies, derived from these antibodies easily crystallize in complex with other proteins. We are currently developing technology to use nanobodies as crystallization chaperones in a systematic approach. This strategy has the potential to aid structure determination of proteins that present particular experimental challenges and are not conducive to more conventional crystallization strategies. Current targets of nanobody aided crystallography include (1) multimerizing proteins such as HIV-Rev, (2) aggregating proteins such as human lysosyme, alpha-synuclein, beta-2-microglobulin and the PrP prion protein (3) larger protein complexes including the bacterial type II secretion system and the trypanosomal RNA editing system and (4) integral membrane proteins including a number of GPCRs and MDRs .