Refolding Increases the Chaperone-like Activity of αH-Crystallin and Reduces Its Hydrodynamic Diameter to That of α-Crystallin

Konstantin O Muranov; Nicolay B Poliansky; Vera A Borzova; Sergey Y Kleimenov

doi:10.3390/ijms241713473

Refolding Increases the Chaperone-like Activity of α_H-Crystallin and Reduces Its Hydrodynamic Diameter to That of α-Crystallin

Int J Mol Sci. 2023 Aug 30;24(17):13473. doi: 10.3390/ijms241713473.

Authors

Konstantin O Muranov¹, Nicolay B Poliansky¹, Vera A Borzova², Sergey Y Kleimenov³

Affiliations

¹ Emanuel Institute of Biochemical Physics of Russian Academy of Sciences, Moscow 119334, Russia.
² Federal Research Centre "Fundamentals of Biotechnology" of Russian Academy of Sciences, Bach Institute of Biochemistry, Moscow 119334, Russia.
³ Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Moscow 119334, Russia.

Abstract

α_H-Crystallin, a high molecular weight form of α-crystallin, is one of the major proteins in the lens nucleus. This high molecular weight aggregate (HMWA) plays an important role in the pathogenesis of cataracts. We have shown that the chaperone-like activity of HMWA is 40% of that of α-crystallin from the lens cortex. Refolding with urea significantly increased-up to 260%-the chaperone-like activity of α-crystallin and slightly reduced its hydrodynamic diameter (D_h). HMWA refolding resulted in an increase in chaperone-like activity up to 120% and a significant reduction of D_h of protein particles compared with that of α-crystallin. It was shown that the chaperone-like activity of HMWA, α-crystallin, and refolded α-crystallin but not refolded HMWA was strongly correlated with the denaturation enthalpy measured with differential scanning calorimetry (DSC). The DSC data demonstrated a significant increase in the native protein portion of refolded α-crystallin in comparison with authentic α-crystallin; however, the denaturation enthalpy of refolded HMWA was significantly decreased in comparison with authentic HMWA. The authors suggested that the increase in the chaperone-like activity of both α-crystallin and HMWA could be the result of the correction of misfolded proteins during renaturation and the rearrangement of protein supramolecular structures.

Keywords: alpha-crystallin; alphaH-crystallin; chaperone; chaperone-like activity; high molecular weight aggregate; refolding; urea.

MeSH terms

Calorimetry, Differential Scanning
Cataract*
Crystallins*
Humans
Hydrodynamics
alpha-Crystallins*

Substances

Crystallins
alpha-Crystallins

Grants and funding

Investigation of the both UV-damaged β_L-crystallin aggregation kinetic and chaperone-like activity of α-crystallin and HMWA was supported by the Russian Science Foundation (grant 21-14-00178). The study of protein particle Dh and thermostability during denaturation and renaturation with urea was funded by the Ministry of Science and Higher Education of the Russian Federation.