Probing the Kinetic Stabilities of Friedreich’s Ataxia Clinical Variants Using a Solid Phase GroEL Chaperonin Capture Platform

Biomolecules

Ana R. Correia¹  Subhashchandra Naik²  Mark T. Fisher² 

[1] Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, EAN, Oeiras 2784-505, Portugal; E-Mail:;Department of Biochemistry and Molecular Biology, Hemenway Life Sciences Innovation Center (HLSIC), University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA; E-Mail:

关键词: clinical mutants;    missense mutants;    frataxin;    Friedreich’s ataxia;    protein folding;    chaperonin;    osmolytes;    protein stability;    protein misfolding and misfolding diseases;   

DOI  :  10.3390/biom4040956

来源: mdpi

【 摘 要 】

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.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.