Ca²⁺ and Myosin Cycle States Work as Allosteric Effectors of Troponin Activation.

ABSTRACT: In cardiac muscle, troponin (Tn) and tropomyosin inhibit actin and myosin interactions through the steric blocking of myosin binding to F-actin. Ca²⁺ binding to Tn C modulates this inhibition. Thin filaments become activated upon Ca²⁺ binding, which enables strong binding of myosin with a concomitant release of ATP hydrolysis products and level arm swinging responsible for force generation. Despite this level of description, the current cross-bridge cycle model does not fully define the structural events that take place within Tn during combinatorial myosin and Ca²⁺ interventions. Here, we studied conformational changes within Tn bound to F-actin and tropomyosin by fluorescence lifetime imaging combined with Förster resonance energy transfer. Fluorescent dy

SUBMITTER: Solis C 

PROVIDER: S-EPMC6225061 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature