1. School of Basic Sciences Indian Institute of Technology Mandi H.P.-175005 India
2. Laboratory of Chemical Biology The Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences Prague 6 16610 Czech Republic
3. Department of Biochemistry, Faculty of Science Charles University Albertov 6 Prague 12843 Czech Republic
4. Department of Computer Science, School of Electrical Engineering and Computer Science KTH Royal Institute of Technology SE-10044 Stockholm Sweden
5. Current address: Department of Computational Biology Indraprastha Institute of Information Technology New Delhi 110020 India
6. Group of Bioconjugation Chemistry Miltenyi Biotec GmbH Friedrich-Ebert-Straße 68 51429 Bergisch Gladbach Germany
7. Centro de Química Estrutural Instituto Superior Técnico Avenida Rovisco Pais 1049-001 Lisboa Portugal