| dc.description.abstract | Disrupted interactions between the skeletal myosin motor protein and its partner protein actin in the repeating sarcomere units that make up muscle fibres have been implicated in potentially life-threatening muscular weakness such as that experienced by congenital myopathy patients. Currently, treatment for these diseases relies on symptomatic therapy only. The direct modulation of the myosin protein to restore muscle function, however, has shown potential to treat myopathies where muscle weakness is related to altered actin-myosin binding. The selective targeting and modulation of myosin to alter and control muscle contraction has in fact shown therapeutic promise in the treatment of cardiovascular diseases. Here, an in-depth computational study of the myosin protein is described. The known binding site of a cardiac myosin selective modulator, and the equivalent region in high quality models of the skeletal myosin motor domain were compared. Small but significant differences in the residue composition and accompanying size, shape and dynamics of the assessed binding sites were identified and translated to the development of skeletal myosin specific molecules. A tailored drug discovery workflow, which exploited skeletal myosin specific binding site features, was developed to identify novel selective compounds. Promising drug candidates, identified based on selectivity and predicted binding affinity to skeletal myosin, were found to adopt common binding orientations and form stabilising and selectivity-defining interactions with recurring skeletal binding site residues. Preliminary work optimising biochemical in vitro assays has been conducted for the future testing of compound effects on myosin motor function. This work is followed by an assessment of the structure and dynamics of the myosin tail, specifically the effects of aberrant post-translational modifications (PTMs). The observed perturbances to the structure of the myosin tail upon phosphorylation of two residues suggest that unusual PTMs may influence myosin function analogously to characterised disease-causing mutations. Small molecule binding sites identified on the surface of the tail could be further investigated for the development of stabilising or PTM-inhibiting compounds. | en_US |
