Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany. schwalb@lmb.uni-muenchen.de|Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany. schwalb@lmb.uni-muenchen.de|Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany. schwalb@lmb.uni-muenchen.de|Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany. schwalb@lmb.uni-muenchen.de|Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany. schwalb@lmb.uni-muenchen.de|Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany. schwalb@lmb.uni-muenchen.de|Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany. schwalb@lmb.uni-muenchen.de|Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany. schwalb@lmb.uni-muenchen.de