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J. P. Synpeptide, E. Grant, J. Keller, A. Geers, and C. Klaus, SynPlex") for support. S.S. is grateful for financial support by the Helmut Horten Foundation. B.I.M. was the recipient of an Alexander von Humboldt Fellowship. A.L.V. was the recipient of an ETH Postdoctoral Fellowship. We thank D. Seebach and A. Eschenmoser for discussion, thanks the Swiss National Science Foundation (31003A_146992/1) and the European Union, vol.8