MgADP Promotes Myosin Head Movement toward Actin at Low [Ca2+] to Increase Force Production and Ca2+-Sensitivity of Contraction in Permeabilized Porcine Myocardial Strips.

ABSTRACT: Myosin cross-bridges dissociate from actin following Mg2+-adenosine triphosphate (MgATP) binding. Myosin hydrolyses MgATP into inorganic phosphate (Pi) and Mg2+-adenosine diphosphate (ADP), and release of these hydrolysis products drives chemo-mechanical energy transitions within the cross-bridge cycle to power muscle contraction. Some forms of heart disease are associated with metabolic or enzymatic dysregulation of the MgATP-MgADP nucleotide pool, resulting in elevated cytosolic [MgADP] and impaired muscle relaxation. We investigated the mechanical and structural effects of increasing [MgADP] in permeabilized myocardial strips from porcine left ventricle samples. Sarcomere length was set to 2.0 µm at 28 °C, and all solutions contained 3% dextran T-500 to compress myofilament lattice spac

SUBMITTER: Awinda PO 

PROVIDER: S-EPMC9737397 | biostudies-literature | 2022 Dec

REPOSITORIES: biostudies-literature