Ionic interactions play a role in the regulatory mechanism of scallop heavy meromyosin

From: Biophysical Journal | Date: August 1, 2003| Author: Geeves, M A; Stafford, W F; Szent-Gyorgyi, A G; Nyitrai, M | Copyright information

ABSTRACT Heavy meromyosin from scallop (scHMM) striated muscle is regulated by calcium binding to the essential light chain. The regulation can be modeled with a calcium-dependent equilibrium between on and off scHMM conformations. The observed rate constant for mant-ADP dissociation from scHMM is calcium dependent, and we show here that it can be used to define the equilibrium constant (K^sub eq^) between on and off conformations. The data show that K^sub eq^ is markedly ionic strength depen...

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