2. Academic Validation
  3. Structure of the human frataxin-bound iron-sulfur cluster assembly complex provides insight into its activation mechanism

Structure of the human frataxin-bound iron-sulfur cluster assembly complex provides insight into its activation mechanism

  • Nat Commun. 2019 May 17;10(1):2210. doi: 10.1038/s41467-019-09989-y.
Nicholas G Fox 1 2,  Xiaodi Yu 3 4,  Xidong Feng 3,  Henry J Bailey 1,  Alain Martelli 5,  Joseph F Nabhan 5,  Claire Strain-Damerell 1,  Christine Bulawa 5,  Wyatt W Yue 6,  Seungil Han 7
Affiliations

Affiliations

  • 1 Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, OX3 7DQ, UK.
  • 2 Merck & Co, 2000 Galloping Hill Rd, Kenilworth, NJ, 07033, USA.
  • 3 Discovery Sciences, Worldwide Research and Development, Pfizer Inc., Eastern Point Road, Groton, CT, 06340, USA.
  • 4 SMPS, Janssen Research and Development, 1400 McKean Rd, Spring House, PA, 19477, USA.
  • 5 Rare Disease Research Unit, Worldwide Research and Development, Pfizer Inc., 610 Main Street, Cambridge, MA, 02139, USA.
  • 6 Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, OX3 7DQ, UK. wyatt.yue@sgc.ox.ac.uk.
  • 7 Discovery Sciences, Worldwide Research and Development, Pfizer Inc., Eastern Point Road, Groton, CT, 06340, USA. seungil.han@pfizer.com.
PMID: 31101807 DOI: 10.1038/s41467-019-09989-y
Abstract

The core machinery for de novo biosynthesis of iron-sulfur clusters (ISC), located in the mitochondria matrix, is a five-protein complex containing the cysteine desulfurase NFS1 that is activated by frataxin (FXN), scaffold protein ISCU, accessory protein ISD11, and acyl-carrier protein ACP. Deficiency in FXN leads to the loss-of-function neurodegenerative disorder Friedreich's ataxia (FRDA). Here the 3.2 Å resolution cryo-electron microscopy structure of the FXN-bound active human complex, containing two copies of the NFS1-ISD11-ACP-ISCU-FXN hetero-pentamer, delineates the interactions of FXN with other component proteins of the complex. FXN binds at the interface of two NFS1 and one ISCU subunits, modifying the local environment of a bound zinc ion that would otherwise inhibit NFS1 activity in complexes without FXN. Our structure reveals how FXN facilitates ISC production through stabilizing key loop conformations of NFS1 and ISCU at the protein-protein interfaces, and suggests how FRDA clinical mutations affect complex formation and FXN activation.

Figures