{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nSCO1 is an essential mitochondrial metallochaperone required for the proper assembly of cytochrome c oxidase (COX). It plays a critical role in facilitating copper delivery to the CuA site in the COX complex, operating in close coordination with its paralog SCO2 and the upstream copper donor COX17. Defects or mutations in SCO1 are linked to tissue‐specific COX deficiencies that underlie distinct clinical phenotypes."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nAt the biochemical level, copper delivery to COX occurs through a finely tuned redox mechanism. Copper-loaded COX17 transfers both Cu(I) and electrons to SCO1, which is subsequently involved in the insertion of copper into the CuA site of COX subunit II. In this context, SCO2 functions upstream by modulating the oxidation state of the copper‐binding cysteines in SCO1, thereby priming SCO1 for effective copper transfer."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "3", "end_ref": "5"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nStructurally, SCO1 undergoes a significant conformational change upon metal binding, shifting from an open, flexible state to a closed, rigid state that is optimal for copper coordination. Its copper-binding domain, characterized by a conserved CPXXCP motif along with additional coordinating residues, is crucial for binding both Cu(I) and, under certain conditions, Cu(II). This precise architecture underpins its ability to selectively transfer Cu(I) ions via specific loop-recognition events."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "6", "end_ref": "8"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nBeyond its role in COX assembly, SCO1 also contributes to the regulation of cellular copper homeostasis. Acting as a metallochaperone, SCO1 ensures appropriate copper distribution within mitochondria and influences broader copper efflux mechanisms, including those mediated by ATP7A. Clinically relevant mutations—such as the P174L substitution—impair the interaction between SCO1 and COX17, compromising copper transfer and leading to both defective COX assembly and altered cellular copper balance, which manifest in diverse tissue-specific pathologies."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "9", "end_ref": "12"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Scot C Leary, Brett A Kaufman, Giovanna Pellecchia, et al. 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"}, {"type": "b", "children": [{"type": "t", "text": "Mitochondrial copper(I) transfer from Cox17 to Sco1 is coupled to electron transfer."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Proc Natl Acad Sci U S A (2008)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1073/pnas.0800019105"}], "href": "https://doi.org/10.1073/pnas.0800019105"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "18458339"}], "href": "https://pubmed.ncbi.nlm.nih.gov/18458339"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Yih-Chern Horng, Scot C Leary, Paul A Cobine, et al. 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"}, {"type": "b", "children": [{"type": "t", "text": "Human SCO2 is required for the synthesis of CO II and as a thiol-disulphide oxidoreductase for SCO1."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Hum Mol Genet (2009)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1093/hmg/ddp158"}], "href": "https://doi.org/10.1093/hmg/ddp158"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "19336478"}], "href": "https://pubmed.ncbi.nlm.nih.gov/19336478"}]}, {"type": "r", "ref": 6, "children": [{"type": "t", "text": "Lucia Banci, Ivano Bertini, Vito Calderone, et al. 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