Unveiling the structural and functional consequences of the p.D109G pathogenic mutation in human αB-Crystallin responsible for restrictive cardiomyopathy and skeletal myopathy

In this study, we generated this mutation in the α-Cry domain (ACD) which is crucial for forming the active chaperone dimeric state, using site-directed mutagenesis. After inducing expression in the bacterial host, we purified the mutant and wild-type recombinant proteins using anion exchange chromatography. Various spectroscopic evaluations revealed significant changes in the secondary, tertiary, and quaternary structures of human αB-Cry caused by this mutation. Furthermore, this pathogenic mutation led to the formation of protein oligomers with larger sizes than those of the wild-type protein counterpart. The mutant protein also exhibited increased chaperone activity and decreased chemical, thermal, and proteolytic stability. Atomic force microscopy (AFM), transmission electron microscopy (TEM), and fluorescence microscopy (FM) demonstrated that p.D109G mutant protein is more prone to forming amyloid aggregates. The misfolding associated with the p.D109G mutation may result in abnormal interactions of human αB-Cry with its natural partners (e.g., desmin), leading to the formation of protein aggregates. These aggregates can interfere with normal cellular processes and may contribute to muscle cell dysfunction and damage, resulting in the pathogenic involvement of the p.D109G mutant protein in restrictive cardiomyopathy and skeletal myopathy.PMID:37939764 | DOI:10.1016/j.ijbiomac.2023.127933

Source: International Journal of Biological Macromolecules - November 8, 2023 Category: Biochemistry Authors: Mehrnaz Hosseini Jafari Mohammad Bagher Shahsavani Masaru Hoshino Jun Hong Ali Akbar Saboury Ali Akbar Moosavi-Movahedi Reza Yousefi Source Type: research