Heterogeneity of Starved Yeast Cells in IF Levels Suggests the Role of This Protein .

In mitochondria, a small protein IF suppresses the hydrolytic activity of ATP synthase and presumably prevents excessive ATP hydrolysis under conditions of energy deprivation. In yeast , IF homologs are encoded by two paralogous genes: and . expression is known to aggravate the deleterious effects of mitochondrial DNA (mtDNA) depletion.

Attenuated ADP-inhibition of FF ATPase mitigates manifestations of mitochondrial dysfunction in yeast.

Proton-translocating FF ATP synthase (F-ATPase) couples ATP synthesis or hydrolysis to transmembrane proton transport in bacteria, chloroplasts, and mitochondria. The primary function of the mitochondrial FF is ATP synthesis driven by protonmotive force (pmf) generated by the respiratory chain. However, when pmf is low or absent (e.

Mutation Q259L in subunit beta in Bacillus subtilis ATP synthase attenuates ADP-inhibition and decreases fitness in mixed cultures.

The ATPase activity of H-FF-ATP synthase (FF) is down-regulated by several mechanisms. The most universal of them found in bacterial, chloroplast and mitochondrial enzymes is non-competitive inhibition by MgADP (ADP-inhibition). When MgADP binds in a catalytic site in the absence of phosphate, the nucleotide might be trapped instead of being released and replaced by new MgATP.

Residue 249 in subunit beta regulates ADP inhibition and its phosphate modulation in Escherichia coli ATP synthase.

ATPase activity of proton-translocating FF-ATP synthase (F-type ATPase or F-ATPase) is suppressed in the absence of protonmotive force by several regulatory mechanisms. The most conservative of these mechanisms found in all enzymes studied so far is allosteric inhibition of ATP hydrolysis by MgADP (ADP-inhibition). When MgADP is bound without phosphate in the catalytic site, the enzyme lapses into an inactive state with MgADP trapped.

Application of Peak Intensity Analysis to Measurements of Protein Binding to Lipid Vesicles and Erythrocytes Using Fluorescence Correlation Spectroscopy: Dependence on Particle Size.

Fluorescence correlation spectroscopy (FCS) is a sensitive analytical tool for investigation of processes accompanied by changes in the mobility of molecules and complexes. In the present work, peak intensity analysis (PIA) in combination with the solution stirring using FCS setup was applied to explore the interaction between fluorescently labeled protein ligands and corresponding receptors located on membranes. In the system composed of biotinylated liposomes and fluorescently labeled streptavidin as a ligand, PIA allowed us to determine the optimum receptor concentration and demonstrate the essential dependence of the binding efficacy on the length of the linker between the biotin group and the polar head group of the lipid.