{"doi":"10.1016/j.jbc.2023.102966","title":"The β-latch structural element of the SufS cysteine desulfurase mediates active site accessibility and SufE transpersulfurase positioning","abstract":"Under oxidative stress and iron starvation conditions, Escherichia coli uses the Suf pathway to assemble iron-sulfur clusters. The Suf pathway mobilizes sulfur via SufS, a type II cysteine desulfurase. SufS is a pyridoxal-5′-phosphate–dependent enzyme that uses cysteine to generate alanine and an active-site persulfide (C 364 -S-S - ). The SufS persulfide is protected from external oxidants/reductants and requires the transpersulfurase, SufE, to accept the persulfide to complete the SufS catalytic cycle. Recent reports on SufS identified a conserved \"β-latch\" structural element that includes the α 6 helix, a glycine-rich loop, a β-hairpin, and a cis -proline residue. To identify a functional role for the β-latch, we used site-directed mutagenesis to obtain the N99D and N99A SufS variants. N99 is a conserved residue that connects the α 6 helix to the backbone of the glycine-rich loop via hydrogen bonds. Our x-ray crystal structures for N99A and N99D SufS show a distorted beta-hairpin and glycine-rich loop, respectively, along with changes in the dimer geometry. The structural disruption of the N99 variants allowed the external reductant TCEP to react with the active-site C364-persulfide intermediate to complete the SufS catalytic cycle in the absence of SufE. The substitutions also appear to disrupt formation of a high-affinity, close approach SufS–SufE complex as measured with fluorescence polarization. Collectively, these findings demonstrate that the β-latch does not affect the chemistry of persulfide formation but does protect it from undesired reductants. The data also indicate the β-latch plays an unexpected role in forming a close approach SufS–SufE complex to promote persulfide transfer.","journal":"Journal of Biological Chemistry","year":2023,"id":339252,"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":16,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9562,"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":1073296,"name":"Franki Carroll","orcid":null,"position":1,"is_corresponding":false},{"id":1073297,"name":"Juliana V. Conte","orcid":null,"position":2,"is_corresponding":false},{"id":927998,"name":"Mohamed Nasef","orcid":"0000-0003-2056-6311","position":3,"is_corresponding":false},{"id":440447,"name":"J.A. Dunkle","orcid":"0000-0001-6252-0587","position":4,"is_corresponding":false},{"id":440448,"name":"Patrick A. Frantom","orcid":"0000-0001-7655-5967","position":5,"is_corresponding":false},{"id":1072839,"name":"Rajleen K. Gogar","orcid":"0000-0002-5032-5749","position":0,"is_corresponding":true}],"reference_count":25,"raw_metadata":null,"created_at":"2026-07-19T01:10:45.048445Z","pmid":"36736428","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":[]}