A Missense Mutation (R723H) in the Head Motor Domain of β-MYH7 gene in an Indian HCM Patient and Phenotypic Plasticity

Mutations in the β-MYH7 gene are one of the major causes that lead to cardiomyopathies. However, to differentiate a causative nsSNP and its impact on protein structure remains a major challenge. In the present study, we detected a missense mutation Arg723His in the head motor domain of β-MYH7 in a HCM patient, and it was absent in 207 healthy individuals. The mutant (R723H) has been found to alter an evolutionarily conserved amino acid. In addition, the mutant (R723H) was predicted pathogenic by Polyphen-2 and SIFT bioinformatic tools. Further, the superimposed 3D structure of the mutant (p.His723 homology model) with native (p. Arg723) displayed the root means square deviation (RMSD) of ~3.38A0. We know that the non-covalent interactions such as hydrophobic, electrostatic, Van der Waals, and hydrogen bonds between amino acids are at the heart of stabilizing protein structures. Here, we demonstrated how the mutant (p.His723) has disrupted a critical non-covalent interactions network at the mutation site and may contribute to the disease phenotype. Hence, our findings in the future could pave the way for developing small molecular modulators or myosin-targeted therapies for heart failure.