Institute for Biochemistry, University of Cologne, Zülpicher Strasse 47, Köln, D-50674, Germany.|Institute for Biochemistry, University of Cologne, Zülpicher Strasse 47, Köln, D-50674, Germany.|Institute for Biochemistry, University of Cologne, Zülpicher Strasse 47, Köln, D-50674, Germany.|Institute for Biochemistry, University of Cologne, Zülpicher Strasse 47, Köln, D-50674, Germany.