Conformational Changes of α-Crystallin Proteins Induced by Heat Stress

• Published in: International journal of molecular sciences Vol. 23; no. 16; p. 9347
• Main Authors: Chang, Yu-Yung, Hsieh, Meng-Hsuan, Huang, Yen-Chieh, Chen, Chun-Jung, Lee, Ming-Tao
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 19.08.2022; MDPI
• Subjects: Cataracts; chaperone activity; Chromatography; Circular dichroism; Crystal structure; Crystallin; Crystallinity; Dichroism; Heat; Heat shock proteins; Heat stress; High temperature; Mammals; Physiology; Protein folding; Proteins; Size exclusion chromatography; Small angle X ray scattering; Stability analysis; Temperature effects; Thermal stability; Vertebrates; X-ray scattering; α-crystallin
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms23169347

α-crystallin is a major structural protein in the eye lenses of vertebrates that is composed of two relative subunits, αA and αB crystallin, which function in maintaining lens transparency. As a member of the small heat-shock protein family (sHsp), α-crystallin exhibits chaperone-like activity to prevent the misfolding or aggregation of critical proteins in the lens, which is associated with cataract disease. In this study, high-purity αA and αB crystallin proteins were expressed from E. coli and purified by affinity and size-exclusion chromatography. The size-exclusion chromatography experiment showed that both αA and αB crystallins exhibited oligomeric complexes in solution. Here, we present the structural characteristics of α-crystallin proteins from low to high temperature by combining circular dichroism (CD) and small-angle X-ray scattering (SAXS). Not only the CD data, but also SAXS data show that α-crystallin proteins exhibit transition behavior on conformation with temperature increasing. Although their protein sequences are highly conserved, the analysis of their thermal stability showed different properties in αA and αB crystallin. In this study, taken together, the data discussed were provided to demonstrate more insights into the chaperone-like activity of α-crystallin proteins.