1. Department of Biochemistry, Faculty of Sciences, P. J. Šafárik University, Kośice, Slovakia, Laboratorium für Biochemie, Universität Bayreuth, Bayreuth, Germany, Department of Biochemistry, The University of Texas Health Science Center, San Antonio, Texas 78229, and Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovakia