Identification of fragments binding to SARS-CoV-2 nsp10 reveals ligand-binding sites in conserved interfaces between nsp10 and nsp14/nsp16

Since the emergence of SARS-CoV-2 in 2019, Covid-19 has developed into a serious threat to our health, social and economic systems. Although vaccines have been developed in a tour-de-force and are now increasingly available, repurposing of existing drugs has been less successful. There is a clear need to develop new drugs against SARS-CoV-2 that can also be used against future coronavirus infections. Non-structural protein 10 (nsp10) is a conserved stimulator of two enzymes crucial for viral replication, nsp14 and nsp16, exhibiting exoribonuclease and methyltransferase activities. Interfering with RNA proofreading or RNA cap formation represents intervention strategies to inhibit replication. We applied fragment-based screening using nano differential scanning fluorometry and X-ray crystallography to identify ligands targeting SARS-CoV-2 nsp10. We identified four fragments located in two distinct sites: one can be modelled to where it would be located in the nsp14–nsp10 complex interface and the other in the nsp16–nsp10 complex interface. Microscale thermophoresis (MST) experiments were used to quantify fragment affinities for nsp10. Additionally, we showed by MST that the interaction by nsp14 and 10 is weak and thereby that complex formation could be disrupted by small molecules. The fragments will serve as starting points for the development of more potent analogues using fragment growing techniques and structure-based drug design

Novel polarized light emitting illumination systems for LCDs

A new, simple polymer-bilayer illumination system is presented which efficiently emits linearly polarized light for use, for example, in liquid crystal displays. Polarization of incoming light is accomplished through polarization-selective reflection at the interface between an optically isotropic light guide and a birefringent top-layer mounted thereon. Light of one polarization direction is coupled-out from the latter layer by means of an appropriate relief structure. Light of the other polarization direction is trapped in the isotropic waveguide and may be recycled, which ultimately permits polarization efficiencies that approach unity

FragMAX The fragment screening platform at the MAX IV Laboratory

Advances in synchrotron storage rings and beamline automation have pushed data-collection rates to thousands of data sets per week. With this increase in throughput, massive projects such as in-crystal fragment screening have become accessible to a larger number of research groups. The quality of support offered at large-scale facilities allows medicinal chemistry-focused or biochemistry-focused groups to supplement their research with structural biology. Preparing the experiment, analysing multiple data sets and prospecting for interesting complexes of protein and fragments require, for both newcomers and experienced users, efficient management of the project and extensive computational power for data processing and structure refinement. Here, FragMAX, a new complete platform for fragment screening at the BioMAX beamline of the MAX IV Laboratory, is described. The ways in which users are assisted in X-ray-based fragment screenings and in which the fourth-generation storage ring available at the facility is best exploited are also described

New insights into complex formation by SARS-CoV-2 nsp10 and nsp14

SARS-CoV-2 non-structural protein 10 (nsp10) is essential for the stimulation of enzymatic activities of nsp14 and nsp16, acting as both an activator and scaffolding protein. Nsp14 is a bifunctional enzyme with the N-terminus containing a 3′-5′ exoribonuclease (ExoN) domain that allows the excision of nucleotide mismatches at the virus RNA 3’-end, and a C-terminal N7-methyltransferase (N7-MTase) domain. Nsp10 is required for stimulating both ExoN proofreading and the nsp16 2’-O-methyltransferase activities. This makes nsp10 a central player in both viral resistance to nucleoside-based drugs and the RNA cap methylation machinery that helps the virus evade innate immunity. We characterised the interactions between full-length nsp10 (139 residues), N- and C-termini truncated nsp10 (residues 10-133), and nsp10 with a C-terminal truncation (residues 1-133) with nsp14 using microscale thermophoresis, multi-detection SEC, and hydrogen-deuterium (H/D) exchange mass spectrometry. We describe the functional role of the C-terminal region of nsp10 for binding to nsp14 and show that full N- and C-termini of nsp10 are important for optimal binding. In addition, our H/D exchange experiments suggest an intermediary interaction of nsp10 with the N7-MTase domain of nsp14. In summary, our results suggest intermediary steps in the process of association or dissociation of the nsp10–nsp14 complex, involving contacts between the two proteins in regions not identifiable by X-ray crystallography alone

Class Attendance and University Performance

Using survey data collected at Göttingen University, Germany, this paper evaluates the effect of attending the lecture and/or tutorial on the grade achieved in two basic courses in business administration and economics. The analysis shows that going to class has no significant impact on student performance in most specifications. Although the identification of a causal effect may not be possible with the data at hand, the results suggest that, in the given framework, attending class and studying on one´s own may be substitutes

Soluble epoxide hydrolase is a susceptibility factor for heart failure in a rat model of human disease

10.1038/ng.129Nature Genetics405529-53