1. a Institute of Organic Chemistry of the Polish Academy of Sciences , Kasprzaka 44/52, 01-224 , Warsaw , Poland
2. b Department of Chemistry , Warsaw University , Pasteura 1, 02-093 , Warsaw , Poland
3. c cInstitut de Biologic et Chimie des Proteines , CNRS UPR 412, 7 passage du Vercors, F69367 , Lyon , Cedex 07 , France