Inhibitor screening assay for neurexin-LRRTM adhesion protein interaction involved in synaptic maintenance and neurological disorders.

Synaptic adhesion molecules, including presynaptic neurexins (NRXNs) and post-synaptic leucine-rich repeat transmembrane (LRRTM) proteins are important for development and maintenance of brain neuronal networks. NRXNs are probably the best characterized synaptic adhesion molecules, and one of the major presynaptic organizer proteins. The LRRTMs were found as ligands for NRXNs. Many of the synaptic adhesion proteins have been linked to neurological cognitive disorders, such as schizophrenia and autism spectrum disorders, making them targets of interest for both biological studies, and towards drug development. Therefore, we decided to develop a screening method to target the adhesion proteins, here the LRRTM-NRXN interaction, to find small molecule probes for further studies in cellular settings. To our knowledge, no potent small molecule compounds against the neuronal synaptic adhesion proteins are available. We utilized the AlphaScreen technology, and developed an assay targeting the NRXN-LRRTM2 interaction. We carried out screening of 2000 compounds and identified hits with moderate IC50-values. We also established an orthogonal in-cell Western blot assay to validate hits. This paves way for future development of specific high affinity compounds by further high throughput screening of larger compound libraries using the methods established here. The method could also be applied to screening other NRXN-ligand interactions.Peer reviewe

Macrodomain binding compound MRS 2578 inhibits alphavirus replication

Peer reviewe

Macrodomain binding compound MRS 2578 inhibits alphavirus replication

Peer reviewe

Adenosine analogs bearing phosphate isosteres as human MDO1 ligands

The human O-acetyl-ADP-ribose deacetylase MDO1 is a mono-ADP-ribosylhydrolase involved in the reversal of post-translational modifications. Until now MDO1 has been poorly characterized, partly since no ligand is known besides adenosine nucleotides. Here, we synthesized thirteen compounds retaining the adenosine moiety and bearing bioisosteric replacements of the phosphate at the ribose 50-oxygen. These compounds are composed of either a squaryldiamide or an amide group as the bioisosteric replacement and/or as a linker. To these groups a variety of substituents were attached such as phenyl, benzyl, pyridyl, carboxyl, hydroxy and tetrazolyl. Biochemical evaluation showed that two compounds, one from both series, inhibited ADP-ribosyl hydrolysis mediated by MDO1 in high concentrations. (C) 2018 Elsevier Ltd. All rights reserved.Peer reviewe

Inhibitor screening assay for neurexin-LRRTM adhesion protein interaction involved in synaptic maintenance and neurological disorders

Abstract Synaptic adhesion molecules, including presynaptic neurexins (NRXNs) and post-synaptic leucine-rich repeat transmembrane (LRRTM) proteins are important for development and maintenance of brain neuronal networks. NRXNs are probably the best characterized synaptic adhesion molecules, and one of the major presynaptic organizer proteins. The LRRTMs were found as ligands for NRXNs. Many of the synaptic adhesion proteins have been linked to neurological cognitive disorders, such as schizophrenia and autism spectrum disorders, making them targets of interest for both biological studies, and towards drug development. Therefore, we decided to develop a screening method to target the adhesion proteins, here the LRRTM-NRXN interaction, to find small molecule probes for further studies in cellular settings. To our knowledge, no potent small molecule compounds against the neuronal synaptic adhesion proteins are available. We utilized the AlphaScreen technology, and developed an assay targeting the NRXN-LRRTM2 interaction. We carried out screening of 2000 compounds and identified hits with moderate IC₅₀-values. We also established an orthogonal in-cell Western blot assay to validate hits. This paves way for future development of specific high affinity compounds by further high throughput screening of larger compound libraries using the methods established here. The method could also be applied to screening other NRXN-ligand interactions

Multiple crystal forms of human MacroD2

Abstract MacroD2 is one of the three human macrodomain proteins characterized by their protein-linked mono-ADP-ribosyl-hydrolyzing activity. MacroD2 is a single-domain protein that contains a deep ADP-ribose-binding groove. In this study, new crystallization conditions for MacroD2 were found and three crystal structures of human MacroD2 in the apo state were solved in space groups P4₁2₁2, P43212 and P4₃, and refined at 1.75, 1.90 and 1.70 Å resolution, respectively. Structural comparison of the apo crystal structures with the previously reported crystal structure of MacroD2 in complex with ADP-ribose revealed conformational changes in the side chains of Val101, Ile189 and Phe224 induced by the binding of ADP-ribose in the active site. These conformational variations may potentially facilitate design efforts of a MacroD2 inhibitor

Two crystal structures of <i>Trichoderma reesei </i>hydrophobin HFBI:The structure of a protein amphiphile with and without detergent interaction

Hydrophobins are small fungal proteins that are highly surface active and possess a unique ability to form amphiphilic membranes through spontaneous self‐assembly. The first crystal structure of a hydrophobin, Trichoderma reesei HFBII, revealed the structural basis for the function of this amphiphilic protein—a patch consisting of hydrophobic side chains on the protein surface. Here, the crystal structures of a native and a variant T. reesei hydrophobin HFBI are presented, revealing the same overall structure and functional hydrophobic patch as in the HFBII structure. However, some structural flexibility was found in the native HFBI structure: The asymmetric unit contained four molecules, and, in two of these, an area of seven residues was displaced as compared to the two other HFBI molecules and the previously determined HFBII structure. This structural change is most probably induced by multimer formation. Both the native and the N‐Cys‐variant of HFBI were crystallized in the presence of detergents, but an association between the protein and a detergent was only detected in the variant structure. There, the molecules were arranged into an extraordinary detergent‐associated octamer and the solvent content of the crystals was 75%. This study highlights the conservation of the fold of class II hydrophobins in spite of the low sequence identity and supports our previous suggestion that concealment of the hydrophobic surface areas of the protein is the driving force in the formation of multimers and monolayers in the self‐assembly process

Crystallization and preliminary diffraction analysis of a β-galactosidase from Trichoderma reesei

The crystallization and preliminary diffraction analysis of a β-galactosidase from T. reesei is described. The crystals diffracted to 1.2 Å resolution

Activation of PARP2/ARTD2 by DNA damage induces conformational changes relieving enzyme autoinhibition

Abstract Human PARP2/ARTD2 is an ADP-ribosyltransferase which, when activated by 5′-phosphorylated DNA ends, catalyses poly-ADP-ribosylation of itself, other proteins and DNA. In this study, a crystal structure of PARP2 in complex with an activating 5′-phosphorylated DNA shows that the WGR domain bridges the dsDNA gap and joins the DNA ends. This DNA binding results in major conformational changes, including reorganization of helical fragments, in the PARP2 regulatory domain. A comparison of PARP1 and PARP2 crystal structures reveals how binding to a DNA damage site leads to formation of a catalytically competent conformation. In this conformation, PARP2 is capable of binding substrate NAD⁺ and histone PARylation factor 1 that changes PARP2 residue specificity from glutamate to serine when initiating DNA repair processes. The structure also reveals how the conformational changes in the autoinhibitory regulatory domain would promote the flexibility needed by the enzyme to reach the target macromolecule for ADP-ribosylation