Ca2+ stabilization of respiratory complex I from Escherichia coli. Issue 12 (12th April 2018) - Belevich, Galina
Abstract: Stability of the membrane-bound and purified H + -translocating NADH:ubiquinone oxidoreductase, Complex I, was studied. The loss of the enzyme activity is strongly increased by alkaline pH and dilution of the sample. Complex I inactivation is prevented specifically by a low concentration of Ca 2+ and/or an intracellular stabilization factor (ISF). The action of both, Ca 2+ and ISF, on Complex I stability is interdependent. The data are discussed in terms of a release of structural Ca 2+ as a reason for Complex I decay and an effect of ISF on the affinity and/or accessibility of Ca 2+ -binding site. Abstract : Calcium ions were found to play a role of keystone in respiratory Complex I structure and an intracellular stabilization factor secures Ca 2+ in the enzyme.