{"id":"d4ada9f8-a820-50ea-a13e-b51584cfe88c","stable_key":"a8baf7e9-80e4-5d8c-adec-9a63e84d2f21:l-cysteine-nfs1-persulfide-gate","predicate":"transfers_persulfide_sulfur_for","statement":"Labeled NFS1-bound persulfide was an intermediate; its sulfur release required iron, GTP and NADH, whereas ATP was required for the overall assembly pathway but not this release step.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"745cfaf9-8484-5c1c-b4d3-2bfd85082f80","mechanism_event_label":"The pathway has several gates, with different requirements at different steps.","subject":{"id":"f5cef903-677c-5210-8a13-37f7626fd89f","slug":"mouse-nfs1","display_name":"Mouse cysteine desulfurase / Nfs1","entity_type_key":"protein"},"object":{"id":"ce29656b-d3bb-542b-b665-27c59cdcbad9","slug":"mouse-mitochondrial-fe-s-assembly","display_name":"Iron–sulfur cluster assembly in isolated mouse-cell mitochondria","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"745cfaf9-8484-5c1c-b4d3-2bfd85082f80","stable_key":"a8baf7e9-80e4-5d8c-adec-9a63e84d2f21:l-cysteine-nfs1-persulfide-gate-event","event_type":"observed_relationship","label":"The pathway has several gates, with different requirements at different steps.","description":"Labeled NFS1-bound persulfide was an intermediate; its sulfur release required iron, GTP and NADH, whereas ATP was required for the overall assembly pathway but not this release step.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"f5cef903-677c-5210-8a13-37f7626fd89f","slug":"mouse-nfs1","display_name":"Mouse cysteine desulfurase / Nfs1","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"ce29656b-d3bb-542b-b665-27c59cdcbad9","slug":"mouse-mitochondrial-fe-s-assembly","display_name":"Iron–sulfur cluster assembly in isolated mouse-cell mitochondria","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"ca899f13-50ad-55e5-ab99-329ae0038c74","slug":"l-cysteine","display_name":"L-Cysteine","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"89bcaf42-b4ab-5760-8c2e-44eace10cee0","slug":"iron","display_name":"Iron","entity_type_key":"nutrient_element"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"c8ccc03a-29cc-5127-baf5-81eeb92ac780","slug":"gtp","display_name":"Guanosine triphosphate","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"9fbf2e03-16a9-5ca7-965c-0bfc07ca24da","slug":"nadh","display_name":"NADH","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""},{"entity":{"id":"58b974f1-d389-5bf6-81cd-889c44442c42","slug":"atp","display_name":"ATP","entity_type_key":"small_molecule"},"role":"context_participant","stoichiometry":null,"state_label":"","sequence_order":6,"notes":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary abstract","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Mouse-cell isolated mitochondrial experiments.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"The proposed GTPase/reductase mediators were not individually established by this study; do not assign a universal ATP requirement to each substep.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"L-Cysteine collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"l-cysteine","display_name":"L-Cysteine","entity_type_key":"small_molecule"}},{"dimension":"plain_language","value_text":"The pathway has several gates, with different requirements at different steps.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Fe-S cluster biogenesis in isolated mammalian mitochondria: coordinated use of persulfide sulfur and iron and requirements for GTP, NADH, and ATP. · 2015 · https://pubmed.ncbi.nlm.nih.gov/25398879/ · DOI 10.1074/jbc.M114.610402","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"f6753da1-5ff1-545d-b8bf-3589ecbfc0a5","evidence_kind":"source_excerpt","locator":"Lines 276-282","start_line":276,"end_line":282,"excerpt":"## l-cysteine-nfs1-persulfide-gate\nThe pathway has several gates, with different requirements at different steps.\nLabeled NFS1-bound persulfide was an intermediate; its sulfur release required iron, GTP and NADH, whereas ATP was required for the overall assembly pathway but not this release step.\nModel: Mouse-cell isolated mitochondrial experiments.\nLimitations: The proposed GTPase/reductase mediators were not individually established by this study; do not assign a universal ATP requirement to each substep.\nEvidence access: Primary abstract\nFe-S cluster biogenesis in isolated mammalian mitochondria: coordinated use of persulfide sulfur and iron and requirements for GTP, NADH, and ATP. · 2015 · https://pubmed.ncbi.nlm.nih.gov/25398879/ · DOI 10.1074/jbc.M114.610402","model_system":"Mouse-cell isolated mitochondrial experiments.","directness":"reported_statement","verification_status":"source_derived_draft","notes":"Original curation paraphrase; evidence access and experimental limitations specified.","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"654560f6-8d7f-596b-8722-48d94053cfe3","stable_key":"import-a8baf7e9-80e4-5d8c-adec-9a63e84d2f21","title":"L-Cysteine: sulfur allocation, redox supply and cross-nutrient mechanisms (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary references, access levels and experimental limitations individually identified. 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