An extended beta-strand mimic for a larger artificial beta-sheet

This paper reports the development of beta-strand mimic B, which duplicates the hydrogen-bonding functionality of one edge of a tetrapeptide beta-strand. When attached to a tripeptide by a suitable Linking group, beta-strand mimic B forms a hydrogen-bonded antiparallel beta-sheet structure, artificial beta-sheet 2. beta-Strand mimic B is based upon a 5-hydrazino-2-methoxybenzoic acid building block. The first half of the paper describes synthetic, IR and H-1 NMR spectroscopic, X-ray crystallographic, and molecular modeling studies of 5-hydrazino-2-methoxybenzoic acid derivatives and related molecules. These studies establish that hydrazide derivatives of 5-hydrazino-2-methoxybenzoic acid adopt a conformation similar to that of a peptide beta-strand and are suitable for use as beta-strand mimics. The second half of the paper describes synthetic and H-1 NMR spectroscopic studies of artificial beta-sheet 2 and of controls 20 and 21, which resemble the peptidomimetic and peptide strands of 2. These experiments indicate that 2 adopts a conformation and hydrogen-bonding pattern similar to that of an antiparallel beta-sheet and establish that beta-strand mimic B can induce beta-sheet formation in an attached peptide strand.