1. Branch of Shemyakin & Ovchinnikov’s Institute of Bioorganic Chemistry RAS, Prospekt Nauki, 6, Pushchino, Moscow region 142290, Russia. Fax: +7-4967-330527; Tel: +7-4967-330527
2. Institute of Theoretical and Experimental Biophysics RAS, Institutskaya ul., 3, Pushchino, Moscow region 142290, Russia