{"doi":"10.1101/2025.04.24.650479","title":"An Enantioselective Chemical Probe for Chikungunya nsP2 Helicase with Antialphaviral Activity","abstract":"Abstract Chikungunya virus (CHIKV) replication relies on the multifunctional nsP2 protein, making it an attractive target for antiviral drug discovery. Here, we report the resolution of oxaspiropiperidine 1 , a first-in-class inhibitor of the CHIKV nsP2 RNA helicase (nsP2hel), into its constitutive enantiomers and characterization of their antiviral activity. The enantiomer ( R )- 1 exhibited potent inhibition of viral replication, nsP2hel ATPase activity, and dsRNA unwinding, while the ( S )- 1 enantiomer was >100-fold less active. The ( R )- 1 enantiomer also demonstrated high selectivity for CHIKV over other RNA viruses and for nsP2hel over other RNA helicases. Direct binding of ( R )- 1 to nsP2hel protein was confirmed by 19 F NMR. Biophysical and structural studies revealed conformational polymorphism in the spirocyclic scaffold of ( R )- 1 , suggesting a potential role of thermal mobility of the ligand in allosteric inhibition of nsP2hel. Collectively, these findings designate ( R )- 1 (RA-NSP2-1) as a high-quality chemical probe and ( S )- 1 (RA-NSP2-1N) as a negative control for probing the biology of alphavirus RNA helicases.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2025,"id":557681,"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":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9555,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1375773,"name":"Hans J. Oh","orcid":"0009-0007-2354-080X","position":1,"is_corresponding":false},{"id":1171587,"name":"John D. Sears","orcid":"0000-0002-4713-2241","position":2,"is_corresponding":false},{"id":588282,"name":"Chun‐Hsing Chen","orcid":"0000-0003-0150-9557","position":3,"is_corresponding":false},{"id":1215549,"name":"Anand Vala","orcid":"0000-0002-2186-820X","position":4,"is_corresponding":false},{"id":32636,"name":"Shubin Liu","orcid":"0000-0001-9331-0427","position":5,"is_corresponding":false},{"id":445078,"name":"Kacey M. Talbot","orcid":"0000-0002-9146-0445","position":6,"is_corresponding":false},{"id":688345,"name":"Mohammad Anwar Hossain","orcid":"0000-0001-8684-8755","position":7,"is_corresponding":false},{"id":36712,"name":"Peter J. Brown","orcid":"0000-0002-8454-0367","position":8,"is_corresponding":false},{"id":36740,"name":"Scott Houliston","orcid":"0000-0002-0113-0339","position":9,"is_corresponding":false},{"id":681930,"name":"Julia Garcia Perez","orcid":"0000-0003-3630-4404","position":10,"is_corresponding":false},{"id":1392008,"name":"Fengling Li","orcid":"0000-0002-6928-414X","position":11,"is_corresponding":false},{"id":1392009,"name":"Meareg Amare","orcid":"0000-0001-7222-9144","position":12,"is_corresponding":false},{"id":107104,"name":"Peter Halfmann","orcid":"0000-0002-1648-1625","position":13,"is_corresponding":false},{"id":726237,"name":"Jessica R. Smith","orcid":"0000-0002-8314-7141","position":14,"is_corresponding":false},{"id":463506,"name":"Alec J. Hirsch","orcid":"0000-0002-8613-0740","position":15,"is_corresponding":false},{"id":84362,"name":"C.H. Arrowsmith","orcid":"0000-0002-4971-3250","position":16,"is_corresponding":false},{"id":277395,"name":"Levon Halabelian","orcid":"0000-0003-4361-3619","position":17,"is_corresponding":false},{"id":614536,"name":"Ava M. Vargason","orcid":"0000-0002-6536-9998","position":18,"is_corresponding":false},{"id":471230,"name":"Rafael M. Couñago","orcid":"0000-0003-1847-5090","position":19,"is_corresponding":false},{"id":337326,"name":"Jamie J. Arnold","orcid":"0000-0002-2345-9776","position":20,"is_corresponding":false},{"id":555983,"name":"Craig E. Cameron","orcid":"0000-0002-7564-5642","position":21,"is_corresponding":false},{"id":1375776,"name":"Nathaniel J. Moorman","orcid":"0009-0008-6391-3268","position":22,"is_corresponding":false},{"id":275061,"name":"Mark T. Heise","orcid":"0000-0001-5829-8477","position":23,"is_corresponding":false},{"id":273796,"name":"Timothy M. Willson","orcid":"0000-0003-4181-8223","position":24,"is_corresponding":false},{"id":1330305,"name":"M. Bose","orcid":"0000-0002-0916-3784","position":0,"is_corresponding":true}],"reference_count":24,"raw_metadata":null,"created_at":"2026-07-19T02:55:21.727661Z","pmid":null,"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":[]}