{"doi":"10.1101/2021.06.21.449194","title":"<i>Mycobacterium tuberculosis</i> DosS binds H <sub>2</sub> S through its Fe <sup>3+</sup> heme iron to regulate the Dos dormancy regulon","abstract":"Abstract Mycobacterium tuberculosis ( Mtb ) senses and responds to host-derived gasotransmitters NO and CO via heme-containing sensor kinases DosS and DosT and the response regulator DosR. Hydrogen sulfide (H 2 S) is an important signaling molecule in mammals, but its role in Mtb physiology is unclear. We have previously shown that exogenous H 2 S can modulate expression of genes in the Dos dormancy regulon via an unknown mechanism(s). Here, we tested the hypothesis that Mtb senses and responds to H 2 S via the DosS/T/R system. Using UV-Vis and EPR spectroscopy, we show that H 2 S binds directly to the ferric (Fe 3+ ) heme of DosS (K D = 5.64 µM) but not the ferrous (Fe 2+ ) form. No interaction with DosT was detected. Thus, the mechanism by which DosS senses H 2 S is different from that for sensing NO and CO, which bind only the ferrous forms of DosS and DosT. Steered Molecular Dynamics simulations show that H 2 S, and not the charged HS - species, can enter the DosS heme pocket. We also show that H 2 S increases DosS autokinase activity and subsequent phosphorylation of DosR, and H 2 S-mediated increases in Dos regulon gene expression is lost in Mtb lacking DosS. Finally, we demonstrate that physiological levels of H 2 S in macrophages can induce Dos regulon genes via DosS. Overall, these data reveal a novel mechanism whereby Mtb senses and responds to a third host gasotransmitter, H 2 S, via DosS-Fe3 + . These findings highlight the remarkable plasticity of DosS and establish a new paradigm for how bacteria can sense multiple gasotransmitters through a single heme sensor kinase. Significance Statement Hydrogen sulfide (H 2 S) is an important signaling molecule in eukaryotes and bacteria, and along with CO and NO, is an important part of host defense against Mycobacterium tuberculosis ( Mtb ). However, the mechanism(s) by which Mtb senses and responds to H 2 S is unknown. Here, we report that the Mtb heme sensor kinase DosS, a known sensor of CO and NO, is also a sensor of H 2 S. We found that H 2 S binds DosS in its ferric (Fe 3+ ) state, which is considered as its inactive state, to induce the Dos dormancy regulon during infection. These data highlight the unusual capacity of Mtb to sense multiple gasotransmitters through a single sensing protein.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2021,"id":225443,"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":0.9618,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":273290,"name":"Joel N. Glasgow","orcid":"0000-0002-2842-7917","position":1,"is_corresponding":false},{"id":438303,"name":"Martín Pettinati","orcid":"0000-0002-8849-2948","position":2,"is_corresponding":false},{"id":285922,"name":"Marcelo A. Martí","orcid":"0000-0002-7911-9340","position":3,"is_corresponding":false},{"id":273289,"name":"Vineel P. Reddy","orcid":"0000-0001-8605-3143","position":4,"is_corresponding":false},{"id":724117,"name":"Swati Basu","orcid":"0000-0001-9214-8085","position":5,"is_corresponding":false},{"id":401869,"name":"Elmira Alipour","orcid":"0000-0003-3507-4010","position":6,"is_corresponding":false},{"id":347800,"name":"Daniel B. Kim‐Shapiro","orcid":"0000-0003-4383-3101","position":7,"is_corresponding":false},{"id":438308,"name":"Darío A. Estrı́n","orcid":"0000-0002-5006-7225","position":8,"is_corresponding":false},{"id":276048,"name":"Jack R. Lancaster","orcid":null,"position":9,"is_corresponding":false},{"id":273298,"name":"Adrie J. C. Steyn","orcid":"0000-0001-9177-8827","position":10,"is_corresponding":false},{"id":495514,"name":"Ritesh Rajesh Sevalkar","orcid":"0000-0002-1694-8854","position":0,"is_corresponding":true}],"reference_count":65,"raw_metadata":null,"created_at":"2026-07-18T23:54:26.581453Z","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":[]}