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Dimeric P-loop ATPase CFD1 and Related Proteins

Sven A Freibert

Sven A Freibert

Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, 35032 Marburg, Germany

LOEWE Zentrum für Synthetische Mikrobiologie SynMikro, 35043 Marburg, Germany

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Jae-Hun Jeoung

Jae-Hun Jeoung

Institut für Biologie, Strukturbiologie/Biochemie, Humboldt-Universität Berlin, 10115 Berlin, Germany

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Oliver Stehling

Oliver Stehling

Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, 35032 Marburg, Germany

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Holger Dobbek

Holger Dobbek

Institut für Biologie, Strukturbiologie/Biochemie, Humboldt-Universität Berlin, 10115 Berlin, Germany

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Roland Lill

Roland Lill

Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, 35032 Marburg, Germany

LOEWE Zentrum für Synthetische Mikrobiologie SynMikro, 35043 Marburg, Germany

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Note added in proof: A recent publication has indicated that the nucleotide-binding protein AF_226 from Archaeoglobus fulgidus (PDB code: 3KB1; Figure ) contains Co rather than Zn ions (JACS 2019 Dec 20. doi: 10.1021/jacs.9b09186).

Abstract

The assembly of iron–sulfur (Fe/S) proteins in living cells requires complex machineries. The initial synthesis of a Fe/S cluster occurs on specialized scaffold proteins rather than on target apoproteins. The scaffold needs to support both facile assembly and ready transfer of clusters to Fe/S trafficking proteins that assist cluster delivery to final recipients. In the cytosolic iron–sulfur protein assembly (CIA) machinery of eukaryotes, the hetero-oligomeric CFD1-NBP35 complex is performing a scaffold function. Both proteins belong to the metal binding P-loop NTPase family whose members typically are involved in metal center assembly. In vivo, Fe/S cluster assembly on CFD1-NBP35 depends on functional nucleotide binding sites in both proteins, a sulfur compound exported from mitochondria, and the CIA electron transfer chain TAH18-DRE2. In vitro, CFD1-NBP35 bind a bridging [4Fe–4S] cluster at two conserved cysteine residues of each protein. The crystal structure of homodimeric CFD1, as a model of the heterodimer, locates these clustercoordinating cysteine residues on exposed loops. The bridging cluster coordination appears to be ideal for both facile cluster assembly and rapid transfer to downstream CIA trafficking proteins. The crucial cellular function of CFD1-NBP35 is indicated by their essential in vivo requirement for assembly of most cytosolic and nuclear Fe/S proteins.

3D Structure

Description unavailable

Crystal structure of dimeric CtCfd1. Ribbon representation of the dimeric structure of Chaetomium thermophilum CtCfd1 (PDB code: 6G2G).

Adapted from reference 1 and UCSF Chimera (E. F. Pettersen, T. D. Goddard, C. C. Huang, G. S. Couch, D. M. Greenblatt, E. C. Meng, T. E. Ferrin, Journal of Computational Chemistry 2004, 25, 1605–1612).2

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