{"doi":"10.1021/jacs.4c01871","title":"Cobalt(II)-Substituted Cysteamine Dioxygenase Oxygenation Proceeds through a Cobalt(III)-Superoxo Complex","abstract":"We investigated the metal-substituted catalytic activity of human cysteamine dioxygenase (ADO), an enzyme pivotal in regulating thiol metabolism and contributing to oxygen homeostasis. Our findings demonstrate the catalytic competence of cobalt(II)- and nickel(II)-substituted ADO in cysteamine oxygenation. Notably, Co(II)-ADO exhibited superiority over Ni(II)-ADO despite remaining significantly less active than the natural enzyme. Structural analyses through X-ray crystallography and cobalt K-edge excitation confirmed successful metal substitution with minimal structural perturbations. This provided a robust structural basis, supporting a conserved catalytic mechanism tailored to distinct metal centers. This finding challenges the proposed high-valent ferryl-based mechanism for thiol dioxygenases, suggesting a non-high-valent catalytic pathway in the native enzyme. Further investigation of the cysteamine-bound or a peptide mimic of N -terminus RGS5 bound Co(II)-ADO binary complex revealed the metal center’s high-spin ( S = 3/2) state. Upon reaction with O 2, a kinetically and spectroscopically detectable intermediate emerged with a ground spin state of S = 1/2. This intermediate exhibits a characteristic 59 Co hyperfine splitting ( A = 67 MHz) structure in the EPR spectrum alongside UV–vis features, consistent with known low-spin Co(III)-superoxo complexes. This observation, unique for protein-bound thiolate-ligated cobalt centers in a protein, unveils the capacities for O 2 activation in such metal environments. These findings provide valuable insights into the non-heme iron-dependent thiol dioxygenase mechanistic landscape, furthering our understanding of thiol metabolism regulation. The exploration of metal-substituted ADO sheds light on the intricate interplay between metal and catalytic activity in this essential enzyme.","journal":"Journal of the American Chemical Society","year":2024,"id":424678,"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":21,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9576,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1221624,"name":"Ran Duan","orcid":"0000-0002-5370-5990","position":1,"is_corresponding":false},{"id":333661,"name":"Aimin Liu","orcid":"0000-0002-4182-8176","position":2,"is_corresponding":false},{"id":774624,"name":"Jiasong Li","orcid":"0000-0003-0341-2038","position":0,"is_corresponding":true}],"reference_count":37,"raw_metadata":null,"created_at":"2026-07-19T01:58:21.523756Z","pmid":"38941563","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":[]}