Each of our projects addresses the mechanisms by which the respective enzymes achieve their fascinating biocatalytic properties. Our structural enzymological studies focus on three different classes of enzymes, being CoA dependent enzymes, triosephosphate ismerases and prolyl 4-hydroxylases. CoA dependent enzymes catalyse thioester dependent reactions, which are important in many pathways in the cell. Many of these enzymes are characterized by having an oxyanion hole as well as reactive catalytic bases and nucleophilic groups. These catalytic tools have been studied in great detail in our project on the CoA-dependent thiolases. Our thiolase studies have been aimed originally to study the structural enzymology properties of each of the six human isoenzymes. We also study thiolases of infectious agents like trypanosomes (causing sleeping sickness) and Mycobacterium tuberculosis (causing tuberculosis). Thiolases occur as monofunctional enzymes, but also as subunits of multifunctional enzymes. The multifunctional enzymes are of special interest, as several active sites assemble into one complex. Substrate channeling between these active sites would allow the reactive intermediates to transfer over the surface of the enzyme to the subsequent active site, without diffusing into bulk solvent.
Triosephosphate isomerases (TIM) are being studied in a structure based directed evolution project for finding novel activities on the TIM-barrel scaffold. The work on prolyl 4-hydroxylases (P4Hs) is focused on crystallising the complete alpha2beta2 tetramer. P4Hs hydroxylate the procollagen polypeptide at multiple sites. P4Hs has two binding sites for its substrate, being a substrate binding domain and a catalytic domain. Our studies are aimed to discover how these two binding sites are assembled with respect to each other and how they function together to facilitate the efficient hydroxylation of the procollagen substrate.
Last updated: 28.10.2016