Dataset about substitution of Mg2+ cofactor with Ca2+ disrupt positive cooperativity in F1FO-ATP(hydrol)ase catalysis

Abstract

This dataset contains data from the evaluation of the hydrolytic activity of mitochondrial F1FO-ATPase, isolated from porcine heart, activated by the natural cofactor Mg²⁺ or replaced by Ca²⁺. The aim of the research was to investigate how replacing the physiological cofactor Mg²⁺ with Ca²⁺ affects the catalysis, cooperativity, and mechanochemical functionality of mitochondrial F1FO-ATPase, in order to understand the molecular mechanisms that determine the transition of the enzyme from its physiological role as an ATP synthase (the "enzyme of life") to its pathological function as a component of the mitochondrial permeability transition pore (mPTP, "enzyme of death"). "F_ATPase_cooperativity_Dataset.zip" contains data on the activity of the Mg2+-dependent F1FO-ATPase, which is more efficient than the Ca2+-dependent activity ("curve_MgATPase.csv" and "curve_CaATPase.csv"). Evaluation of the cooperativity of the Mg²⁺- and Ca²⁺-dependent F1FO-ATPase revealed a differential cooperative effect on the ATP substrate, depending on the specific cofactor involved. A loss of cooperativity is evident when Mg²⁺ ("nHi_MgATPase.csv") is replaced with Ca²⁺ ("nHi_CaATPase.csv"). Data from experiments investigating the kinetics of the cofactors interacting with the enzyme are reported in "Inhibition mechanism.csv", which show a reduction in kinetic parameters in presence of Ca2+, suggesting uncompetitive inhibition