1 University of Ljubljana, Medical Faculty, Institute of Biochemistry and Molecular Genetics, Vrazov trg 2, 1000Ljubljana, Slovenia, zorko@mf.uni-lj.si.
2 University of Stockholm, Department of Biochemistry and Biophysics, Svante Arrhenius väg 16, 106 91 Stockholm, Sweden, ulo.langel@dbb.su.se, and Institute of Technology, University of Tartu, Nooruse 1, Tartu, Estonia, 50411.