Zn2+‐Complexation by a β‐Peptidic Helix and Hairpin Containing β3hCys and β3hHis Building Blocks: Evidence from CD Measurements. Preliminary Communication |
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Authors: | Francesco Rossi Grald Lelais Dieter Seebach |
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Institution: | Francesco Rossi,Gérald Lelais,Dieter Seebach |
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Abstract: | Two new β3‐homohistidine‐ and β3‐homocysteine‐containing β‐peptides have been prepared by solid‐phase synthesis. A β‐octapeptide ( 2 ) contains seven β3‐amino acids and one β2‐amino acid. The β2/β3 segment has been placed in the middle of this peptide, which contains β3‐amino acids of alternating configuration, to induce the formation of a hairpin secondary structure. A β‐decapeptide ( 3 ) has been designed to fold to a 314‐helical secondary structure with neighboring His side chains in 6‐ and 9‐positions. Circular‐dichroism (CD) measurements show the capability of both peptides to bind Zn2+ ions in aqueous solution. In the case of the β‐octapeptide, binding of Zn2+ causes a dramatic change of the CD spectrum, indicating a change or a stabilization of its secondary structure. Zn2+ Ions clearly stabilize the 314‐helix of the β‐decapeptide, in neutral and basic solution. For the construction of the two new β‐peptides, we needed to have a supply of the β‐amino acid derivatives Fmoc‐β3hCys(Trt)‐OH and Fmoc‐β3hHis(Trt)‐OH, the preparation of which is described herein. |
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