Interdomain Force Dispersion within Spectrin Repeats of Dystrophin and its Influence on Secondary Structure

Abstract

Dystrophin is a large protein complex that connects the cytoskeleton to the extracellular matrix and functions to stabilize muscle cells when force is applied. Dystrophin consists of four domains; an actin binding domain (ABD-1), triple helical spectrin domains composed of 24 spectrin repeats (SR’s), and cysteine rich domain, and the C terminal domain. Mutations, even single point mutations, within the dystrophin gene are known to cause muscular dystrophy, a condition characterized by progressive weakness of the muscles. The fact that single point mutations can result in muscular dystrophy support the idea the domains must communicate with each other. It has been hypothesized that dystrophin exhibits negative interdomain coupling mechanism, meaning that as force is dispersed across the domains, domains destabilize each other and adopt multiple conformations. This negative coupling mechanism is being tested on the spectrin repeats of dystrophin and the actin binding domain. This presentation discusses the data analysis method used to calculate free energy using differential scanning calorimetry, the conclusions drawn thus far from data obtained, and analyzes circular dichroism data to predict secondary structures of the constructs.