Biology subjects

Wierenga, R. K.

Publications and source records attributed to Wierenga, R. K..

3 recordsLinked to original sources

bioRxiv2026

Targeting collagen biosynthesis by small molecules inhibiting the function of the peptide-substrate-binding domain of collagen prolyl 4-hydroxylases

Collagen prolyl 4-hydroxylase (C-P4H) is an essential enzyme in collagen synthesis and known to be a potential target for drugs that prevent excess collagen formation. Currently known C-P4H inhibitors target the catalytic site of C-P4H, being analogues of 2-oxoglutarate (2OG). However, in mammalian cells there are many other 2OG-dependent dioxygenases with a highly similar catalytic domain, which limits the selective specificity of drugs targeting C-P4H activity. The peptide-substrate-binding (PSB) domain is unique for the C-P4H family and known to be important for the catalytic efficiency of C-P4H. Therefore, interfering with peptide binding to the PSB domain might allow more specific inhibition of the hydroxylation activity of C-P4Hs. We developed a robust FRET-based high-throughput screening assay (Z > 0.73) based on PSB-peptide interactions. This assay was used to screen a peptidomimetic library of 15614 compounds with the PSB domains of C-P4H isoforms I and II. A hit compound (OUL-PSBi-001) was identified with IC50s of 40 {micro}M and 62 {micro}M for PSB-I and PSB-II, respectively. We also showed that this compound indeed inhibits the catalytic activity of the full-length CP4H-I and -II. This FRET assay provides a new strategy for finding selective inhibitors for the treatment of fibrotic diseases and cancer.

molecular biology↗

bioRxiv2024

Crystallographic fragment binding studies of the Mycobacterium tuberculosis trifunctional enzyme suggest binding pockets for the tails of the acyl-CoA substrates at its active sites and a potential substrate channeling path between them

The Mycobacterium tuberculosis trifunctional enzyme (MtTFE) is an 2{beta}2 tetrameric enzyme in which the -chain harbors the 2E-enoyl-CoA hydratase (ECH) and 3S-hydroxyacyl-CoA dehydrogenase (HAD) active sites, and the {beta}-chain provides the 3-ketoacyl-CoA thiolase (KAT) active site. Linear, medium, and long chain 2E-enoyl-CoA molecules are the preferred substrates of MtTFE. Previous crystallographic binding and modelling studies have identified binding sites for the acyl-CoA substrates at the three active sites as well as the NAD+ binding pocket at the HAD active site. These studies have also identified three additional CoA binding sites on the surface of MtTFE that are different from the active sites. It has been proposed that one of these additional sites could be of functional relevance for substrate channeling (by surface crawling) of reaction intermediates between the three active sites. Here, in a crystallographic fragment binding study with MtTFE crystals 226 fragments were screened, resulting in the structures of 17 MtTFE-fragment complexes. Analysis of the 143 fragment binding events shows that the ECH active site is the binding hotspot for the tested fragments, with 50 binding events. The mode of binding of the fragments bound at the active sites provides additional insight on how the long chain acyl moiety of the substrates can be accommodated at their proposed binding pockets. In addition, the 24 fragment binding events between the active sites identify potential transient binding sites of reaction intermediates relevant for possible channeling of substrates between these active sites. These results provide a basis for further studies to understand the functional relevance of these binding sites and to identify substrates for which channeling is crucial. SynopsisCrystallographic fragment binding studies of the Mycobacterium tuberculosis trifunctional enzyme (MtTFE) have resulted in 143 binding events of 17 fragments out of 226 investigated fragments, suggesting functional sites with respect to substrate binding and substrate channeling.

biochemistry↗

bioRxiv2020

Structure of transmembrane prolyl 4-hydroxylase reveals unique organization of EF and dioxygenase domains

Prolyl 4-hydroxylases (P4Hs) catalyze post-translational hydroxylation of peptidyl proline residues. In addition to collagen P4Hs and hypoxia-inducible factor P4Hs, a poorly characterized endoplasmic reticulum (ER)-localized transmembrane prolyl 4-hydroxylase (P4H-TM) is found in animals. P4H-TM variants are associated with the familiar neurological HIDEA syndrome. Here, the 3D structure of the soluble human P4H-TM was solved using X-ray crystallography. The structure revealed an EF-domain with two Ca2+-binding motifs inserted to the catalytic domain. A substrate-binding cavity was formed between the EF-domain and the catalytic domain. The active site contained bound Fe2+ and N-oxalylglycine. Comparison to homologous structures complexed with peptide substrates showed that the substrate interacting residues and the lid structure that folds over the substrate are conserved in P4H-TM. Differences to homologs were found in the extensive loop structures that surround the substrate-binding cavity and generate a negative surface charge. Ca2+-binding affinity of P4H-TM was determined to be within the range of physiological Ca2+ concentration in the ER. The proximity of the EF-domain to the active site suggests that Ca2+-binding is relevant to the catalytic activity. P4H-TM was found both as a monomer and a dimer in solution, but the monomer-dimer equilibrium was not regulated by Ca2+. The solved 3D structure suggests that the HIDEA variants cause loss of P4H-TM function. In conclusion, P4H-TM shares key structural elements with the known P4Hs while possessing a unique property among the 2-oxoglutarate-dependent dioxygenases having an EF-domain and a catalytic activity potentially regulated by Ca2+.

biochemistry↗