Low temperature and omecamtiv mecarbil affect the regulatory state of the thick filament of cardiac myocytes in diastole

Abstract

In the cardiac muscle during diastole myosin motors are packed in helical tracks on the surface of the thick filament, folded toward the centre of the sarcomere unable to bind actin (OFF state, Woodhead et al. 2005, Nature 436:1195-1199). In the X-ray diffraction pattern, the regulatory state of the thick filament is marked by the intensity of the 1st myosin layer-line (IML1), spacing of the 6th order-meridional reflection (SM6) and intensity and fine structure of the 3rd order-meridional reflection (M3) (Reconditi et al.