{"id":"fb98a6a5-827e-5086-8528-aef64a6a0caf","stable_key":"2921131d-0ba0-51d3-8f59-8c4be3b9ac08:cucurbitacin-e-cofilin-sites","predicate":"modifies_cysteine_sites_on","statement":"Mass spectrometry localized cucurbitacin E modification to cofilin Cys39, Cys80 and Cys139, with weaker evidence for Cys147.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"9d8091ce-fb9d-5917-bc37-74a81816e5dc","mechanism_event_label":"The study identifies individual protein attachment sites.","subject":{"id":"d5631638-0ee3-537f-b7cc-cbd4958395d3","slug":"cucurbitacin-e","display_name":"Cucurbitacin E","entity_type_key":"small_molecule"},"object":{"id":"b3d1d81d-9166-5e06-9e8e-c5136d5f874c","slug":"human-cfl1","display_name":"Human cofilin 1 / CFL1","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"9d8091ce-fb9d-5917-bc37-74a81816e5dc","stable_key":"2921131d-0ba0-51d3-8f59-8c4be3b9ac08:cucurbitacin-e-cofilin-sites-event","event_type":"observed_relationship","label":"The study identifies individual protein attachment sites.","description":"Mass spectrometry localized cucurbitacin E modification to cofilin Cys39, Cys80 and Cys139, with weaker evidence for Cys147.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"d5631638-0ee3-537f-b7cc-cbd4958395d3","slug":"cucurbitacin-e","display_name":"Cucurbitacin E","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"b3d1d81d-9166-5e06-9e8e-c5136d5f874c","slug":"human-cfl1","display_name":"Human cofilin 1 / CFL1","entity_type_key":"protein"},"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":""}]},"contexts":[{"dimension":"evidence_access","value_text":"Primary full text PMC3751690","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Purified human cofilin 1 biochemical mapping.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"A protein cysteine residue is not equivalent to free dietary cysteine; these data do not quantify nutritional depletion.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Cucurbitacins collection; species, compartment, exposure, co-substrates and manipulation remain explicit.","comparator":null,"unit":null,"notes":"","entity":{"slug":"cucurbitacin","display_name":"Cucurbitacins","entity_type_key":"chemical_species"}},{"dimension":"plain_language","value_text":"The study identifies individual protein attachment sites.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"Cucurbitacin covalent bonding to cysteine thiols: the filamentous-actin severing protein Cofilin1 as an exemplary target. · 2013 · https://pubmed.ncbi.nlm.nih.gov/23945128/ · DOI 10.1186/1478-811X-11-58","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"0539034d-3c38-56ca-8ecf-1d90ffc0b6c4","evidence_kind":"source_excerpt","locator":"Lines 36-42","start_line":36,"end_line":42,"excerpt":"## cucurbitacin-e-cofilin-sites\nThe study identifies individual protein attachment sites.\nMass spectrometry localized cucurbitacin E modification to cofilin Cys39, Cys80 and Cys139, with weaker evidence for Cys147.\nModel: Purified human cofilin 1 biochemical mapping.\nLimitations: A protein cysteine residue is not equivalent to free dietary cysteine; these data do not quantify nutritional depletion.\nEvidence access: Primary full text PMC3751690\nCucurbitacin covalent bonding to cysteine thiols: the filamentous-actin severing protein Cofilin1 as an exemplary target. · 2013 · https://pubmed.ncbi.nlm.nih.gov/23945128/ · DOI 10.1186/1478-811X-11-58","model_system":"Purified human cofilin 1 biochemical mapping.","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":"77324310-00ce-5d28-9fc7-595fddae86b9","stable_key":"import-2921131d-0ba0-51d3-8f59-8c4be3b9ac08","title":"Cucurbitacins: thiol chemistry, cytoskeleton, metabolic dependencies and signaling (2026-09-20)","document_type":"imported_text","citation_label":"AI-assisted research curation; primary references, access levels and experimental limitations individually identified. 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