[3Fe-4S] iron-sulfur cluster: molecular mechanisms & dependencies

How nutrients influence it

Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.

Human evidence only

How nutrients reach it in more than one step

Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.

Tracing routes…

What it does

Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.

Recorded relationships

Where it participates (unsigned role)

Human complex II structure and EPR resolved SDHB-associated [2Fe-2S], [4Fe-4S] and [3Fe-4S] redox centers adjacent to its SDHA FAD system.
Human succinate dehydrogenase iron-sulfur subunit / SDHB → [4Fe-4S] iron-sulfur cluster source_derived_draftungraded
Experimental context and source evidence
cross_nutrient
B2-derived FAD and iron-containing redox centers cooperate within one respiratory complex.
evidence_spans
[{"source_bundle": "artifacts/riboflavin_metabolism_sources.json", "source_key": "PMC10161127", "locator": "XML .//body//p", "paragraph_index": 2, "char_start": 0, "char_end": 1105, "evidence_access": "full-text"}]
experimental_model
Human complex II purified from HEK293F cells, cryo-EM, EPR and succinate-quinone activity assays.
exposure
No nutrient intervention; structural or biochemical characterization.
limitations
Structural co-dependence does not show that B2 corrects iron deficiency or that iron supplementation improves this reaction.
nutrient_topic
Riboflavin research collection; topical membership is not evidence of a direct dietary effect. · Riboflavin (vitamin B2)
organism
Homo sapiens
plain_language
Complex II couples a B2-derived flavin with separate iron-sulfur centers.
primary_references
[du-2023-human-complex-ii] Structure of the human respiratory complex II (2023). https://pubmed.ncbi.nlm.nih.gov/37098072/ DOI: 10.1073/pnas.2216713120
tissue_or_cell_type
HEK293F-derived purified complex II
Riboflavin: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 649–661
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human complex II purified from HEK293F cells, cryo-EM, EPR and succinate-quinone activity assays. · source_derived_draft · unverified_draft
### b2-met-human-sdhb-iron-sulfur Human complex II structure and EPR resolved SDHB-associated [2Fe-2S], [4Fe-4S] and [3Fe-4S] redox centers adjacent to its SDHA FAD system. Condition category: normal nutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Complex II couples a B2-derived flavin with separate iron-sulfur centers. organism: Homo sapiens tissue_or_cell_type: HEK293F-derived purified complex II experimental_model: Human complex II purified from HEK293F cells, cryo-EM, EPR and succinate-quinone activity assays. limitations: Structural co-dependence does not show that B2 corrects iron deficiency or that iron supplementation improves this reaction. exposure: No nutrient intervention; structural or biochemical characterization. cross_nutrient: B2-derived FAD and iron-containing redox centers cooperate within one respiratory complex. evidence_spans: [{"source_bundle": "artifacts/riboflavin_metabolism_sources.json", "source_key": "PMC10161127", "locator": "XML .//body//p", "paragraph_index": 2, "char_start": 0, "char_end": 1105, "evidence_access": "full-text"}] [du-2023-human-complex-ii] Structure of the human respiratory complex II (2023). https://pubmed.ncbi.nlm.nih.gov/37098072/ DOI: 10.1073/pnas.2216713120
Complete structured claim and evidence
Crystallography captured LIAS cross-linked to its H-protein substrate through a 6-mercaptooctanoyl ligand at a [3Fe-4S] cluster.
Lipoic acid synthetase / LIAS → LIAS-GCSH 6-mercaptooctanoyl [3Fe-4S] intermediate source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/ala-research/40640146.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "292f83149906d0c3be473ce3b23be4ee13d1c662b2665993808021098523cd23", "start_char": 0, "end_char": 953, "text_sha256": "292f83149906d0c3be473ce3b23be4ee13d1c662b2665993808021098523cd23"}
experimental_model
X-ray structures of catalytic stages with human lipoyl synthase
exposure
Structural trapping of sulfur-insertion intermediates
limitations
Structural snapshots establish reaction intermediates, not clinical nutrient requirements.
nutrient_topic
Alpha-lipoic acid research collection; topical membership is not evidence of a direct dietary effect. · Lipoic acid
organism
Human recombinant proteins
plain_language
One sulfur-insertion intermediate temporarily links the enzyme, its iron-sulfur cluster and its substrate.
primary_references
[ala-p40640146] Structural basis for catalysis by human lipoyl synthase. (2025). https://pubmed.ncbi.nlm.nih.gov/40640146/ DOI: 10.1038/s41467-025-61393-x
tissue_or_cell_type
LIAS and H-protein substrate
Alpha-lipoic acid: cofactor assembly, redox signaling and nutrient interactions (2026-09-17) · lines 273–284
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · X-ray structures of catalytic stages with human lipoyl synthase · source_derived_draft · unverified_draft
### ala-lias-trapped-intermediate Crystallography captured LIAS cross-linked to its H-protein substrate through a 6-mercaptooctanoyl ligand at a [3Fe-4S] cluster. Condition category: normal nutrient_topic: Alpha-lipoic acid research collection; topical membership is not evidence of a direct dietary effect. plain_language: One sulfur-insertion intermediate temporarily links the enzyme, its iron-sulfur cluster and its substrate. organism: Human recombinant proteins tissue_or_cell_type: LIAS and H-protein substrate experimental_model: X-ray structures of catalytic stages with human lipoyl synthase limitations: Structural snapshots establish reaction intermediates, not clinical nutrient requirements. exposure: Structural trapping of sulfur-insertion intermediates evidence_span: {"source_cache": "artifacts/ala-research/40640146.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "292f83149906d0c3be473ce3b23be4ee13d1c662b2665993808021098523cd23", "start_char": 0, "end_char": 953, "text_sha256": "292f83149906d0c3be473ce3b23be4ee13d1c662b2665993808021098523cd23"} [ala-p40640146] Structural basis for catalysis by human lipoyl synthase. (2025). https://pubmed.ncbi.nlm.nih.gov/40640146/ DOI: 10.1038/s41467-025-61393-x
Complete structured claim and evidence

The events it takes part in

A mechanism often involves more than two components. These are the full events, with every participant and its role.

Situations it appears in

Low-supply and faulty-machinery situations recorded in the chapters where this component plays a part.

In the sources

Preserved passages that mention this component, quoted exactly. Open one to read it in context.

Open hypotheses

Proposed ideas that involve this component. They are labeled as hypotheses and do not change any recorded statement.

This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.

[3Fe-4S] iron-sulfur cluster