{"doi":"10.1101/2023.08.28.555062","title":"Discovery of 2-amide-3-methylester thiophenes that target SARS-CoV-2 Mac1 and repress coronavirus replication, validating Mac1 as an anti-viral target","abstract":"Abstract The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has made it clear that further development of antiviral therapies will be needed to combat additional SARS-CoV-2 variants or novel CoVs. Here, we describe small molecule inhibitors for SARS-CoV-2 Mac1, which counters ADP-ribosylation mediated innate immune responses. The compounds inhibiting Mac1 were discovered through high-throughput screening (HTS) using a protein FRET-based competition assay and the best hit compound had an IC 50 of 14 µM. Three validated HTS hits have the same 2-amide-3-methylester thiophene scaffold and the scaffold was selected for structure-activity relationship (SAR) studies through commercial and synthesized analogs. We studied the compound binding mode in detail using X-ray crystallography and this allowed us to focus on specific features of the compound and design analogs. Compound 27 (MDOLL-0229) had an IC 50 of 2.1 µM and was generally selective for CoV Mac1 proteins after profiling for activity against a panel of viral and human ADP-ribose binding proteins. The improved potency allowed testing of its effect on virus replication and indeed, 27 inhibited replication of both MHVa prototype CoV, and SARS-CoV-2. Furthermore, sequencing of a drug-resistant MHV identified mutations in Mac1, further demonstrating the specificity of 27. Compound 27 is the first Mac1 targeted small molecule demonstrated to inhibit coronavirus replication in a cell model. This, together with its well-defined binding mode, makes 27 a good candidate for further hit/lead-optimization efforts.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2023,"id":391954,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":6,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9585,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2023-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1165173,"name":"Tomi A. O. Parviainen","orcid":"0000-0002-3402-6378","position":1,"is_corresponding":false},{"id":962177,"name":"Jessica J. Pfannenstiel","orcid":"0009-0003-0783-3208","position":2,"is_corresponding":false},{"id":1165174,"name":"Men Thi Hoai Duong","orcid":"0000-0002-1845-7186","position":3,"is_corresponding":false},{"id":1165175,"name":"Daniel Cluff","orcid":"0000-0001-7182-8903","position":4,"is_corresponding":false},{"id":1165176,"name":"Sven T. Sowa","orcid":"0000-0001-7411-5925","position":5,"is_corresponding":false},{"id":1165177,"name":"Albert Galera‐Prat","orcid":"0000-0002-6334-3428","position":6,"is_corresponding":false},{"id":416689,"name":"Dana Ferraris","orcid":"0000-0001-5791-5939","position":7,"is_corresponding":false},{"id":1165178,"name":"Mirko M. Maksimainen","orcid":"0000-0001-8586-9538","position":8,"is_corresponding":false},{"id":109648,"name":"Anthony R. Fehr","orcid":"0000-0003-1560-1573","position":9,"is_corresponding":false},{"id":1165179,"name":"Juha P. Heiskanen","orcid":"0000-0002-1884-1583","position":10,"is_corresponding":false},{"id":618539,"name":"L. Lehtiö","orcid":"0000-0001-7250-832X","position":11,"is_corresponding":false},{"id":873605,"name":"Sarah Wazir","orcid":"0000-0003-0133-2923","position":0,"is_corresponding":true}],"reference_count":51,"raw_metadata":null,"created_at":"2026-07-19T01:18:52.232318Z","pmid":"38234730","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}