Using highly sensitive fluorescent probes, a team of scientists from the University of Connecticut has captured the never-before-seen structural dynamics of an important protein channel inside the cell's primary power plant – the mitochondrion.
The University of Connecticut team's study found that the channel complex - known as the translocase of the inner mitochondrial membrane 23 or TIM23 – is not only directly coupled to the energized state of the mitochondrial inner membrane as scientists have long suspected, it also changes its fundamental structure - altering the helical shape of protein segments that line the channel - when voltage along the membrane's electrical field drops.
It also shows how fluorescent mapping at the subcelllar level may reveal new insights into the underlying causes of neurodegenerative and metabolic disorders associated with mitochondrial function.
In an overview of the research accompanying the paper's publication, Nikolaus Pfanner of the University of Freiberg in Germany and an international leader in the field of cellular protein trafficking, and several members of his research group, called the study "a major step towards a molecular understanding of a voltage-gated protein translocase."
"The molecular nature of voltage sensors in membrane proteins is a central question in biochemical research," Pfanner and his colleagues said. "The study…is not only of fundamental importance for our understanding of mitochondrial biogenesis, but also opens up new perspectives in the search for voltage-responsive elements in membrane proteins."