Researchers Develop Proton Pump of Respiratory Chain Work in a Synthetic Cell

Researchers from the Max Planck Institute for Dynamics of Complex Technical Systems in Magdeburg, the Max Planck Institute of Colloids and Interfaces in Potsdam, and the University of Halle are constructing a synthetic cell. They have used an enzyme found in bacteria to assemble one crucial part of the respiratory chain and made it functional in an artificial polymer membrane.
“We want to construct a new cell from scratch by gradually combining individual components into a living system with a metabolism,” says Ivan Ivanov, a scientist from the working group of Kai Sundmacher, Director at the Max Planck Institute in Magdeburg. In a recent study, the researchers looked for an artificial polymer that has the properties of a cell membrane and could also play its role in energy metabolism. The researchers have found a polymer (the surfactant PDMS-g-PEO) that acts as a membrane in place of the natural phospholipids and can thus form vesicles. The team of Max Planck scientists have integrated the proton pump bo3 oxidase into the synthetic membrane. The oxidase reduces oxygen also in the artificial membrane and thus constitutes the final step of cellular respiration. As the researchers have shown, the enzyme pumps protons into the interior of the vesicle, thereby creating a prerequisite for the production of ATP. The artificial membrane is also nearly impermeable to protons, yet sufficiently fluid and highly stable against harmful oxygen radicals. The bending rigidity of the polymer membrane is also similar to that of a natural membrane.