A community effort in SARS-CoV-2 drug discovery.

peer reviewedThe COVID-19 pandemic continues to pose a substantial threat to human lives and is likely to do so for years to come. Despite the availability of vaccines, searching for efficient small-molecule drugs that are widely available, including in low- and middle-income countries, is an ongoing challenge. In this work, we report the results of an open science community effort, the "Billion molecules against Covid-19 challenge", to identify small-molecule inhibitors against SARS-CoV-2 or relevant human receptors. Participating teams used a wide variety of computational methods to screen a minimum of 1 billion virtual molecules against 6 protein targets. Overall, 31 teams participated, and they suggested a total of 639,024 molecules, which were subsequently ranked to find 'consensus compounds'. The organizing team coordinated with various contract research organizations (CROs) and collaborating institutions to synthesize and test 878 compounds for biological activity against proteases (Nsp5, Nsp3, TMPRSS2), nucleocapsid N, RdRP (only the Nsp12 domain), and (alpha) spike protein S. Overall, 27 compounds with weak inhibition/binding were experimentally identified by binding-, cleavage-, and/or viral suppression assays and are presented here. Open science approaches such as the one presented here contribute to the knowledge base of future drug discovery efforts in finding better SARS-CoV-2 treatments.R-AGR-3826 - COVID19-14715687-CovScreen (01/06/2020 - 31/01/2021) - GLAAB Enric

Nature-Inspired Total Synthesis of (−)-Fusarisetin A

A concise, protecting group-free total synthesis of (−)-fusarisetin A (<b>1</b>) was efficiently achieved in nine steps from commercially available (<i>S</i>)-(−)-citronellal. The synthetic approach was inspired by our proposed biosynthesis of <b>1</b>. Key transformations of our strategy include a facile construction of the decalin moiety that is produced via a stereoselective IMDA reaction and a one-pot TEMPO-induced radical cyclization/aminolysis that forms the C ring of <b>1</b>. Our route is amenable to analogue synthesis for biological evaluation

The relationship of brevetoxin ‘length’ and A-ring functionality to binding and activity in neuronal sodium channels

Background: Brevetoxins are polyether ladder toxins that are ichthyotoxic at nanomolar concentrations. They bind to voltage-gated sodium channels, causing four distinct electrophysiological effects: (i) a shift of activation potential; (ii) occurrence of subconductance states; (iii) induction of longer mean open times of the channel; and (iv) inhibition of channel inactivation. We set out to determine whether these functions all require the same structural elements within the brevetoxin molecules

The relationship of brevetoxin \u27length\u27 and A-ring functionality to binding and activity in neuronal sodium channels

Background: Brevetoxins are polyether ladder toxins that are ichthyotoxic at nanomolar concentrations. They bind to voltage-gated sodium channels, causing four distinct electrophysiological effects: (i) a shift of activation potential; (ii) occurrence of subconductance states; (iii) induction of longer mean open times of the channel; and (iv) inhibition of channel inactivation. We set out to determine whether these functions all require the same structural elements within the brevetoxin molecules. Results: Several synthetically prepared structural analogs of brevetoxin B were examined in synaptosome receptor binding assays and by functional electrophysiological measurements. A truncated analog is not ichthyotoxic at micromolar concentrations, shows decreased receptor-binding affinity, and causes only a shift of activation potential without affecting mean open times or channel inactivation. An analog with the A-ring carbonyl removed binds to the receptor with nanomolar affinity, produces a shift of activation potential and inhibits inactivation, but does not induce longer mean open times. An analog in which the A-ring diol is reduced shows low binding affinity, yet populates five subconductance states. Conclusions: Our data are consistent with the hypothesis that binding to sodium channels requires an elongated cigar-shaped molecule, ∼30 Å long. The four electrophysiological effects of the brevetoxins are not produced by a single structural feature, however, since they can be decoupled by using modified ligands, which are shown here to be partial sodium channel agonists. We propose a detailed model for the binding of brevetoxins to the channel which explains the differences in the effects of the brevetoxin analogs. These studies also offer the potential for developing brevetoxin antagonists