Stretching the Flexible Myosin II Subfragment Using the Novel Gravitational Force Spectroscope, and the Uncoiling of S2

摘要: Familial Hypertrophic cardiomyopathy (HCM) causes ventricle walls to thicken and often leads sudden death especially in adults. Mutations the subfragment 2 (S2) of β-cardiac myosin are implicated genetic disorder. This S2 region is a coiled-coil rod resulting from dimeric form II. It has been proposed that an elastic quality allows normal absorb force during powerstroke according sliding filament model. To test flexibility single molecules against levels physiological force, Gravitational Force Spectrometer (GFS) being developed. novel system employs standard microscope on equatorial mount spectrometer be rotated freely space. Stationary glass beads attached slide where molecule tethered between stationary bead smaller mobile bead. The GFS oriented so gravity can act impart small subfragment. Additionally, video conjunction with ImageJ software makes distance measurement possible resolution around 11 nm. stretched parallel or perpendicular coiled coil elucidate different structural properties rod. study first show evidence vertebrate skeletal uncoils proportionally loads. Because this, usefulness promise highlighted, biological role S2's directly commented on. If dimer undergoes uncoiling at loads as shown, then it reasonable think this might occur nature response stress molecule. unwinding could mechanism protect muscle fiber.