Crystal Structure of Miner1: The Redox-active 2Fe-2S Protein Causative in Wolfram Syndrome 2

Andrea R. Conlan, Herbert L. Axelrod, Aina E. Cohen, Edward C. Abresch, John Zuris, David Yee, Rachel Nechushtai, Patricia A. Jennings*, Mark L. Paddock

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

108 Scopus citations

Abstract

The endoplasmic reticulum protein Miner1 is essential for health and longevity. Mis-splicing of CISD2, which codes for Miner1, is causative in Wolfram Syndrome 2 (WFS2) resulting in early onset optic atrophy, diabetes mellitus, deafness and decreased lifespan. In knock-out studies, disruption of CISD2 leads to accelerated aging, blindness and muscle atrophy. In this work, we characterized the soluble region of human Miner1 and solved its crystal structure to a resolution of 2.1 Å (R-factor = 17%). Although originally annotated as a zinc finger, we show that Miner1 is a homodimer harboring two redox-active 2Fe-2S clusters, indicating for the first time an association of a redox-active FeS protein with WFS2. Each 2Fe-2S cluster is bound by a rare Cys3-His motif within a 17 amino acid segment. Miner1 is the first functionally different protein that shares the NEET fold with its recently identified paralog mitoNEET, an outer mitochondrial membrane protein. We report the first measurement of the redox potentials (Em) of Miner1 and mitoNEET, showing that they are proton-coupled with Em ∼ 0 mV at pH 7.5. Changes in the pH sensitivity of their cluster stabilities are attributed to significant differences in the electrostatic distribution and surfaces between the two proteins. The structural and biophysical results are discussed in relation to possible roles of Miner1 in cellular Fe-S management and redox reactions.

Original languageAmerican English
Pages (from-to)143-153
Number of pages11
JournalJournal of Molecular Biology
Volume392
Issue number1
DOIs
StatePublished - 11 Sep 2009

Bibliographical note

Funding Information:
This work was supported by grants from the NIH grants GM 41637 (to M. Okamura and M.L.P.), and GM54038 and DK54441 (to P.A.J.). Students were supported by HEME and CMG training grants. R. N. thanks the Zevi Hermann Shapira Foundation for supporting the collaborative USA-Israeli efforts. We thank Christopher L. Rife at the Joint Center for Structural Genomics (JCSG) for providing an automated programming script for coordinate validation, Mitch Miller at SSRL and JCSG for helpful discussions on the data collection and processing, and Mel Okamura and JCSG for helpful discussions and support. Parts of this research were carried out at the Stanford Synchrotron Radiation Laboratory, a national user facility operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences. The SSRL Structural Molecular Biology Program is supported by the Department of Energy, Office of Biological and Environmental Research, and by the National Institutes of Health, National Center for Research Resources, Biomedical Technology Program, and the National Institute of General Medical Sciences.

Keywords

  • CDGSH
  • ER stress
  • diabetes
  • membrane bound
  • oxidative stress

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