University Potsdam, Institute for Biochemistry and Biology, Haus 20, Germany. steuer@agnld.uni-potsdam.de|University Potsdam, Institute for Biochemistry and Biology, Haus 20, Germany. steuer@agnld.uni-potsdam.de|University Potsdam, Institute for Biochemistry and Biology, Haus 20, Germany. steuer@agnld.uni-potsdam.de|University Potsdam, Institute for Biochemistry and Biology, Haus 20, Germany. steuer@agnld.uni-potsdam.de|University Potsdam, Institute for Biochemistry and Biology, Haus 20, Germany. steuer@agnld.uni-potsdam.de|University Potsdam, Institute for Biochemistry and Biology, Haus 20, Germany. steuer@agnld.uni-potsdam.de