Photosystem-I (green) is optically excited by an electrode (top). An electron then is transferred step by step in only 16 nanoseconds. A team of scientists, led by Joachim Reichert, Johannes Barth, and Alexander Holleitner (Technische Universitaet Muenchen, Clusters of Excellence MAP and NIM), and Itai Carmeli (Tel Aviv University) developed a method to measure photocurrents of a single functionalized photosynthetic protein system. The scientists could demonstrate that such a system can be integrated and selectively addressed in artificial photovoltaic device architectures while retaining their biomolecular functional properties. The proteins represent light-driven, highly efficient single-molecule electron pumps that can act as current generators in nanoscale electric circuits. The interdisciplinary team publishes the results in ´Nature Nanotechnology´ this week.