Probing the Kinetic Stabilities of Friedreich's Ataxia Clinical Variants Using a Solid Phase GroEL Chaperonin Capture Platform
Abstract
Numerous human diseases are caused by protein folding defects where the protein may become more susceptible to degradation or aggregation. Aberrant protein folding can affect the kinetic stability of the proteins even if these proteins appear to be soluble in vivo. Experimental discrimination between functional properly folded and misfolded nonfunctional conformers is not always straightforward at near physiological conditions. The differences in the kinetic behavior of two initially folded frataxin clinical variants were examined using a high affinity chaperonin kinetic trap approach at 25 °C. The kinetically stable wild type frataxin (FXN) shows no visible partitioning onto the chaperonin. In contrast, the clinical variants FXN-p.Asp122Tyr and FXN-p.Ile154Phe kinetically populate partial folded forms that tightly bind the GroEL chaperonin platform. The initially soluble FXN-p.Ile154Phe variant partitions onto GroEL more rapidly and is more kinetically liable. These differences in kinetic stability were confirmed using differential scanning fluorimetry. The kinetic and aggregation stability differences of these variants may lead to the distinct functional impairments described in Friedreich's ataxia, the neurodegenerative disease associated to frataxin functional deficiency. This chaperonin platform approach may be useful for identifying small molecule stabilizers since stabilizing ligands to frataxin variants should lead to a concomitant decrease in chaperonin binding.
Additional Information
© 2014 Published by MDPI AG, Basel, Switzerland. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0). Received: 5 February 2014; in revised form: 29 August 2014; Accepted: 19 September 2014; Published: 20 October 2014. This paper is dedicated to the memories of Kerri and Jason Werner. This work was initially supported by grants from the Kaufmann Institute for Advancement of Medical Innovation (IAMI) (Mark T. Fisher), by the Fundação para a Ciência e Tecnologia (FCT/MCTES, Portugal) research grants PTDC/SAU-GMG/70033/2006 and PTDC/EBB-BIO/117793/2010 (to Cláudio M. Gomes) and by the National Ataxia Foundation (research grant to Cláudio M. Gomes). Ana R. Correia was recipient of a Fundação para a Ciência e Tecnologia Ph.D. Fellowship (SFRHBD/24949/2005). Author Contributions: Ana R. Correia and Subhashchandra Naik designed and performed experiments, analyzed data and wrote the paper. Mark T. Fisher and Cláudio M. Gomes conceived the study, designed experiments analyzed data and wrote the paper. The authors declare no conflict of interest.Attached Files
Published - biomolecules-04-00956.pdf
Supplemental Material - biomolecules-04-00956-s001.pdf
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Additional details
- PMCID
- PMC4279165
- Eprint ID
- 92479
- Resolver ID
- CaltechAUTHORS:20190125-141739775
- Kaufmann Institute for Advancement of Medical Innovation (IAMI)
- PTDC/SAU-GMG/70033/2006
- Fundação para a Ciência e Tecnologia (FCT)
- PTDC/EBB-BIO/117793/2010
- Fundação para a Ciência e Tecnologia (FCT)
- National Ataxia Foundation
- SFRHBD/24949/2005
- Fundação para a Ciência e Tecnologia (FCT)
- Created
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2019-01-29Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field