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Synthesis and secondary structure of oligo(α‐isobutyl β, L ‐aspartate)s
Author(s) -
GarcíaMartín M. G.,
GarcíaAlvarez M.,
Martínez de Ilarduya A.,
Campos L.,
Galbis J. A.,
MuñozGuerra S.
Publication year - 2005
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.20191
Subject(s) - chemistry , stereochemistry
The oligo(β‐peptide)s, hexa(α‐isobutyl β, L ‐aspartate) (Hex‐AIBLA) and octa(α‐isobutyl β, L ‐aspartate) (Oct‐AIBLA), were synthesized in solution by using standard coupling methods. Powder x‐ray diffraction showed that the octamer crystallized in the two helical crystal forms known to exist in the homologous poly(β‐peptide), whereas the hexamer seemed to adopt an extended conformation. Both CD and 1 H‐NMR spectra of Oct‐AIBLA in MeOH revealed the presence of a regularly folded conformation in this solvent, presumably the 3 14 helix. The helix‐to‐coil transition of Oct‐AIBLA was observed to take place upon heating in both MeOH and CHCl 3 , in the second case associated with a not‐well‐defined aggregation–disaggregation process. The spectroscopic evidence obtained on the presence of folded structures in Hex‐AIBLA were much weaker than for the octamer. © 2005 Wiley Periodicals, Inc. Biopolymers, 2005