Journal of the American Chemical Society 2005-01-19

Chain-length-dependent helical motifs and self-association of beta-peptides with constrained side chains.

Anasztázia Hetényi, István M Mándity, Tamás A Martinek, Gábor K Tóth, Ferenc Fülöp

Index: J. Am. Chem. Soc. 127(2) , 547-53, (2005)

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Abstract

Homo-oligomers constructed by using trans-2-aminocyclohexanecarboxylic acid monomers without protecting groups were studied. Both ab initio theory and NMR measurements showed that the tetramer tends to adopt a 10-helix motif, while the pentamer and hexamer form the known 14-helix. It was concluded that the conformationally constrained backbone is flexible enough to afford both 10-helical and 14-helical motifs, this observation in turn providing evidence of the true folding process. Self-association of the helical units was also detected, and the results of variable-temperature diffusion NMR measurements strongly suggested the presence of helical bundles in methanol solution.