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Quantitative analysis of the impact of a human pathogenic mutation on the CCT5 chaperonin subunit using a proxy archaeal ortholog

Published

Author(s)

Darion Spigolon, David Travis Gallagher, Adrian Velazquez-Campoy, Donatella Bulone, Jatin Narang, Pier San Biagio, Francesco Cappello, Alberto J. Macario, Everly Conway de Macario, Frank Robb

Abstract

The human chaperonin complex is a 1 MDa nanomachine composed of two octameric rings formed from eight similar but non-identical subunits called CCT. Here, we are elucidating the mechanism of a heritable CCT5 subunit mutation that causes profound neuropathy in humans. In previous work, we introduced an equivalent mutation in an archaeal chaperonin that assembles into two octameric rings like in humans but in which all subunits are identical. We reported that the hexadecamer formed by the mutant subunit is unstable with impaired chaperoning functions. This study quantifies the loss of structural stability in the hexadecamer due to the pathogenic mutation, using differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC). The disassembly of the wild type complex, which is tightly coupled with subunit denaturation, was decoupled by the mutation without affecting the stability of individual subunits. Our results verify the effectiveness of the homo-hexadecameric archaeal chaperonin as a proxy to assess the impact of subtle defects in heterologous systems with mutations in a single subunit.
Citation
Biochemistry and Biophysics Reports
Volume
12

Keywords

chaperonopathies, chaperones, CCT5, Pyrococcus furiosus, chaperonin, differential scanning calorimetry, isothermal titration calorimetry, HPLC, circular dichroism, distal neuropathy

Citation

Spigolon, D. , Gallagher, D. , Velazquez-Campoy, A. , Bulone, D. , Narang, J. , San Biagio, P. , Cappello, F. , Macario, A. , de Macario, E. and Robb, F. (2017), Quantitative analysis of the impact of a human pathogenic mutation on the CCT5 chaperonin subunit using a proxy archaeal ortholog, Biochemistry and Biophysics Reports, [online], https://doi.org/10.1016/j.bbrep.2017.07.011 (Accessed October 3, 2022)
Created November 30, 2017, Updated October 12, 2021