RESUMO
Given the crucial role of the main protease (Mpro) in the replication cycle of SARS-CoV-2, this viral cysteine protease constitutes a high-profile drug target. We investigated peptidomimetic azapeptide nitriles as auspicious, irreversibly acting inhibitors of Mpro. Our systematic approach combined an Mpro active-site scanning by combinatorially assembled azanitriles with structure-based design. Encouraged by the bioactive conformation of open-chain inhibitors, we conceptualized the novel chemotype of macrocyclic azanitriles whose binding mode was elucidated by cocrystallization. This strategy provided a favorable entropic contribution to target binding and resulted in the development of the extraordinarily potent Mpro inhibitor 84 with an IC50 value of 3.23 nM and a second-order rate constant of inactivation, kinac/Ki, of 448,000 M-1s-1. The open-chain Mpro inhibitor 58, along with the macrocyclic compounds 83 and 84, a broad-spectrum anticoronaviral agent, demonstrated the highest antiviral activity with EC50 values in the single-digit micromolar range. Our findings are expected to promote the future development of peptidomimetic Mpro inhibitors as anti-SARS-CoV-2 agents.
Assuntos
Antivirais , Proteases 3C de Coronavírus , Nitrilas , SARS-CoV-2 , Antivirais/farmacologia , Antivirais/química , Antivirais/síntese química , SARS-CoV-2/efeitos dos fármacos , Nitrilas/química , Nitrilas/farmacologia , Nitrilas/síntese química , Proteases 3C de Coronavírus/antagonistas & inibidores , Proteases 3C de Coronavírus/metabolismo , Proteases 3C de Coronavírus/química , Relação Estrutura-Atividade , Humanos , Compostos Macrocíclicos/farmacologia , Compostos Macrocíclicos/química , Compostos Macrocíclicos/síntese química , Tratamento Farmacológico da COVID-19 , Descoberta de Drogas , Inibidores de Proteases/farmacologia , Inibidores de Proteases/química , Inibidores de Proteases/síntese química , Peptidomiméticos/farmacologia , Peptidomiméticos/química , Peptidomiméticos/síntese química , Inibidores de Cisteína Proteinase/farmacologia , Inibidores de Cisteína Proteinase/química , Inibidores de Cisteína Proteinase/síntese química , Peptídeos/química , Peptídeos/farmacologia , Peptídeos/síntese químicaRESUMO
Coumarins represent well-established structures to introduce fluorescence into tool compounds for biochemical investigations. They are valued for their small size, chemical stability and accessibility as well as their tunable photochemical properties. As components of fluorophore/quencher pairs or FRET donor/acceptor pairs, coumarins have frequently been applied in substrate mapping approaches for serine and cysteine proteases. This review also focuses on the incorporation of coumarins into the side chain of amino acids and the exploitation of the resulting fluorescent amino acids for the positional profiling of protease substrates. The protease-inhibiting properties of certain coumarin derivatives and the utilization of coumarin moieties to assemble activity-based probes for serine and cysteine proteases are discussed as well.