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Structural Characterization and Functional Analysis of Human Αb-Crystallin With the P.R11g Mutation: Insights Into Cataractogenesis and Cardiomyopathy Publisher Pubmed



Salehi A1 ; Bahrami Z1 ; Shahsavani MB2 ; Somee LR1 ; Stroylova YY3 ; Zarei I4 ; Amanlou M4 ; Hemmati M1 ; Muronetz VI3 ; Saboury AA5 ; Moosavimovahedi AA5 ; Yousefi R1
Authors
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Authors Affiliations
  1. 1. Protein Chemistry Laboratory (PCL), Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran
  2. 2. Department of Biology, Shiraz University, Shiraz, Iran
  3. 3. Belozersky Research Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, Bld 40, Moscow, 119991, Russian Federation
  4. 4. Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
  5. 5. Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran

Source: International Journal of Biological Macromolecules Published:2025


Abstract

αB-crystallin, a member of the small heat-shock protein family, functions as a molecular chaperone and plays a critical role in maintaining cellular homeostasis by preventing the aggregation of misfolded proteins in various tissues. This research investigates the structural and functional consequences of the p.R11G mutation in human αB-crystallin, which is associated with serious health issues, including cataracts, myofibrillar myopathy, and dilated cardiomyopathy. Following the introduction of this mutation through site-directed mutagenesis, the mutant protein was expressed in a prokaryotic host system and purified using ion-exchange chromatography. The structure and stability of the mutant protein were assessed using various spectroscopic techniques. Moreover, the oligomeric structure of the mutant protein was examined using dynamic light scattering and atomic force microscopy. To evaluate the chaperone activity and cytoprotective effects of the protein, UV–Vis spectroscopy and the 2,5-diphenyl-2H-tetrazolium bromide (MTT) assay were utilized. The results demonstrated that the p.R11G mutation significantly alters the protein's structure, leading to enhanced thermal and chemical stability, and formation of the larger oligomers compared to the wild-type protein. Additionally, the mutation was found to increase the protein's chaperone activity and its capacity to inhibit cancer cell death under oxidative stress conditions. Based on the results of our study, the significant changes observed in the structure and activity of human αB-crystallin due to this mutation elucidate the potential role of the mutated chaperone in cataract formation and myopathy. Further research is necessary to fully elucidate the underlying mechanisms and translate these findings into effective therapeutic interventions. © 2025 Elsevier B.V.