1. Protein Modelling Group, HAS-ELTE Institute of Chemistry, Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary, Dipartimento di Chimica ‘G.Ciamician’, Università di Bologna, Via Selmi 2, 40126 Bologna, Italy, and Laboratory of Structural Chemistry and Biology, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary