The biochemical association between R157H mutation in human αB-crystallin and development of cardiomyopathy: Structural and functional analyses of the mutant protein

• Published in: Biochimie Vol. 190; pp. 36 - 49
• Main Authors: Nasiri, Parto, Ghahramani, Maryam, Tavaf, Zohreh, Niazi, Ali, Moosavi-Movahedi, Ali Akbar, Kurganov, Boris I., Yousefi, Reza
• Format: Journal Article
• Language: English
• Published: France Elsevier B.V 01.11.2021
• Subjects: alpha-Crystallin B Chain - chemistry; alpha-Crystallin B Chain - genetics; alpha-Crystallin B Chain - metabolism; Amyloid - metabolism; Cardiomyopathies - genetics; Cardiomyopathy; Chaperone; Circular Dichroism; Dynamic Light Scattering; Escherichia coli - genetics; Escherichia coli - metabolism; Humans; Molecular Chaperones - metabolism; Mutagenesis, Site-Directed; Mutant Proteins - chemistry; Mutant Proteins - genetics; Mutant Proteins - metabolism; Point Mutation; Protein Conformation; Protein Folding; Protein Stability; Proteolysis; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Spectrometry, Fluorescence; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis, Raman; Stability; Structural analyses; Temperature; αB-crystallin; Structural analyses; Stability; Cardiomyopathy; αB-crystallin; Chaperone
• ISSN: 0300-9084; 1638-6183
• DOI: 10.1016/j.biochi.2021.06.019

In human αB-crystallin or HspB5, the substitution of arginine residue at position 157 with histidine has been reported to cause cardiomyopathy. In this study, the impact of R157H mutation on the structure, stability and functional properties of human αB-crystallin was investigated using a variety of spectroscopic techniques and microscopic analyses. Our spectroscopic analyses revealed that this mutation has a negligible impact on the secondary and tertiary structures of HspB5 but its quaternary structure underwent fundamental changes. Although the chemical stability of the mutant protein remained largely unchanged, the differential scanning calorimetry (DSC) measurement suggested that its thermal stability was reduced. As examined with transmission electron microscopy, αB-crystallin and its mutant indicated a similar tendency for the amyloid fibril formation under thermochemical stress. Dynamic light scattering (DLS) analysis suggested important changes in the quaternary (oligomeric) structures of the mutant protein as compared with the native protein counterpart. Also, the mutant protein indicated an improved chaperone-like activity under in vitro assessment. In a pH-dependent manner, the side chains of arginine and histidine have different capabilities for establishing hydrogen bonds and electrostatic interaction (salt bridge) and this variation may be sufficient to produce the larger changes that ultimately alter the interaction of this protein with other target proteins. Overall, the pathogenic contribution of this mutation in cardiomyopathy can be explained by its role in quaternary structure/stability alteration of the mutated protein. [Display omitted] •The R157H mutation in human αB-crystallin causes cardiomyopathy.•This mutation was introduced into CRYAB gene.•The mutant protein was expressed in Escherichia coli and then purified.•The structural and functional features of the mutant protein were analyzed.•The R157H mutant protein indicated both altered quaternary structure and stability.