Testing Dystrophin's Spectrin Repeats Mechanism of Function with Computer Simulations

Abstract

Dystrophin is a cytoplasmic protein and it is an integral part of the protein complex that connects the cytoskeleton of a muscle fiber to the surrounding extracellular matrix. Mutations in dystrophin are responsible for muscular dystrophy, and an understanding of dystrophin’s mechanism of function is the first step towards the development of therapies. Twenty four spectrinrepeat (SR) domains constitute the bulk of dystrophin, and the goal of this research was to test whether coupling multiple repeats affects the force required to unfold them under mechanical stress. To this end, we investigated with molecular dynamics simulations the structure, dynamics, and response to mechanical stress of the repeat SR-17 and of the dimer SR-17:18.