At the start of the cycle a myosin head lacking a bound nucleotide is locked tightly onto an actin filament in a rigor conformation. Troponin-C has bound four calcium ions. In an actively contracting muscle this state is very short-lived, being rapidly terminated by the binding of a molecule of ATP.
|10747208||Regulation of contraction in striated muscle||Physiol Rev||2000|
|Regulatory Mechanisms of Striated Muscle Contraction||Advances in Experimental Medicine and Biology||2007|