{"doi":"10.1101/2025.07.28.667264","title":"CH•••S hydrogen bonds drive molecular recognition of ergothioneine by the microbial transporter","abstract":"Abstract Many bacteria harbor an ATP-binding cassette (ABC) transporter named EgtU specific for the human dietary antioxidant and 2-thioimidazole-containing low molecular weight thiol ergothioneine (ET). How the solute binding domain, EgtUC, discriminates among ET and other similar molecules is unknown. Here, we use a “chimeric” mutagenesis strategy and two distantly related EgtUCs from Streptococcus pneumoniae and Helicobacter pylori to show that a suite of EgtUC alkyl CH•••S hydrogen bonds to the ET thione S atom are central determinants of molecular recognition. Small perturbations in CH•••S distance and angle give rise to sharply attenuated transport-competent ET-bound “closed” state lifetimes and increased motional disorder in the binding pocket, not around the S atom itself, but distally in weakening NH•••O hydrogen bonds. This is, to our knowledge, the first work to describe the impact of alkyl CH•••S H-bonding in a biological protein-ligand complex in water.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2025,"id":571495,"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":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9582,"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":456383,"name":"Giovanni González-Gutiérrez","orcid":"0000-0002-1044-943X","position":1,"is_corresponding":false},{"id":344078,"name":"Katherine A. Edmonds","orcid":"0000-0002-1282-9858","position":2,"is_corresponding":false},{"id":1477229,"name":"Philip Shushkov","orcid":"0009-0000-6989-7416","position":3,"is_corresponding":false},{"id":229018,"name":"David Giedroc","orcid":"0000-0002-2342-1620","position":4,"is_corresponding":false},{"id":867666,"name":"Katherine A. Legg","orcid":"0000-0002-3508-8765","position":0,"is_corresponding":true}],"reference_count":48,"raw_metadata":null,"created_at":"2026-07-19T02:57:15.755535Z","pmid":"40766558","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":[]}