Stepwise C-Terminal Truncation of Cardiac Troponin T Alters Function at Low and Saturating Ca².

ABSTRACT: Activation of striated muscle contraction occurs in response to Ca²⁺ binding to troponin C. The resulting reorganization of troponin repositions tropomyosin on actin and permits activation of myosin-catalyzed ATP hydrolysis. It now appears that the C-terminal 14 amino acids of cardiac troponin T (TnT) control the level of activity at both low and high Ca²⁺. We made a series of C-terminal truncation mutants of human cardiac troponin T, isoform 2, to determine if the same residues of TnT are involved in the low and high Ca²⁺ effects. We measured the effect of these mutations on the normalized ATPase activity at saturating Ca²⁺. Changes in acrylodan tropomyosin fluorescence and the degree of Ca²⁺ stimulation of the rate of binding of rigo

SUBMITTER: Johnson D 

PROVIDER: S-EPMC6104287 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature