Computational analysis of missense mutations in dystrophin protein: Insights into domain-specific effects and functional implications

Abstract

BackgroundDystrophin is a structural protein primarily found in skeletal muscles that connects trans-membrane component of dystrophin-glycoprotein complex to the intracellular cytoskeleton network. N-terminal domain of dystrophin binds to F-actin and its C-terminal domain attaches to dystrophin-associated complex (DAG) in the membrane. It serves as the bridge connecting the extracellular matrix to the actin based cytoskeleton of muscle cells across the plasma membrane. This complex works together to strengthen muscle fibers and shield them from damage as they contract and relax. ObjectiveOur Objective is to investigate the different pathogenic mutations in four distinct domains of dystrophin protein and to decipher how these mutations impact protein structure and function. In this study, we investigated the impact of disease causing missense mutations in isoforms of dystrophin – P.11532–1 (K18N.A165V, D3187G, F3228L); P11532–4 (Y223N, D3179G) and P-11532-11 (Y227N,D3183G).Occurrence of pathogenic mutations in dystrophin might compromise structural stability, interfere with protein-protein interactions or alter cellular signaling pathways collectively. All these can contribute to the progressive muscle degeneration observed in Duchene or Becker muscular dystrophy(DMD or BMD) and X-lined dilated cardiomyopathy(CMD3B) affected individuals. MethodsEvolutionary conservation analysis using multiple sequence alignment followed by pathogenicity prediction using web based server was performed. Homology modeling of mutants was performed bySWISS MODEL a fully automated homology-modeling server, accessible through the Expasy web server. These models were then analyzed using various servers such as Dynamut. Pymol was used for visualization and structural analysis. ResultsAnalyzed mutations cause structural instability by either gaining or losing specific interactions involved in the folding of protein. Loss of pi-pi stacking interactions has the potential to significant impact the overall stability of the protein. It is important to note that the majority of the mutations lead to stability defects rather than functional defects, ultimately contributing to different forms of muscular dystrophy. ConclusiónThe mutations in different domains of Dystrophin protein significantly alters the protein structure. This may in turn impact its ability to interact with other proteins. Understanding the specific impacts of these mutations can pave the way for development of targeted therapies that aims at restoring functionality of dystrophin and ameliorating the debilitating effects of muscular dystrophy.