Comparative conformational analysis of peptides based on the two C<sup>α</sup>-tetrasubstituted, C<sup>β</sup>-branched, chiral α-amino acids (αMe)Dip and (αMe)ValExperimental procedures for the synthesis of the new derivatives and peptides are available as supplementary data. For direct electronic access see http://www.rsc.org/suppdata/p2/a9/a909856i. See Instructions for Authors available via the RSC web page (http://www.rsc.org/authors).The NMR spectra of the new derivatives and peptides are available as supplementary data from BLDSC (SUPPL. NO. 57694, pp. 16) or the RSC Library. See Instructions for Authors available via the RSC web page (http://www.rsc.org/authors).
Lapeña, Yolanda; Lopez, Pilar; Cativiela, Carlos; Kaptein, Bernard; Broxterman, Quirinus B.; Kamphuis, Johan; Mossel, Eric; Peggion, Cristina; Formaggio, Fernando; Crisma, Marco; Toniolo, Claudio; Lapeña Yolanda; Department of Organic Chemistry, Institute of Materials Science of Aragon, University of Zaragoza-CSIC; Lopez Pilar; Department of Organic Chemistry, Institute of Materials Science of Aragon, University of Zaragoza-CSIC; Cativiela Carlos; Department of Organic Chemistry, Institute of Materials Science of Aragon, University of Zaragoza-CSIC; Kaptein Bernard; DSM Research, Organic Chemistry and Biotechnology Section; Broxterman Quirinus B.; DSM Research, Organic Chemistry and Biotechnology Section; Kamphuis Johan; DSM Specialty Intermediates; Mossel Eric; Biopolymer Research Centre, CNR, Department of Organic Chemistry, University of Padova; Peggion Cristina; Biopolymer Research Centre, CNR, Department of Organic Chemistry, University of Padova; Formaggio Fernando; Biopolymer Research Centre, CNR, Department of Organic Chemistry, University of Padova; Crisma Marco; Biopolymer Research Centre, CNR, Department of Organic Chemistry, University of Padova; Toniolo Claudio; Biopolymer Research Centre, CNR, Department of Organic Chemistry, University of Padova
Журнал:
Journal of the Chemical Society, Perkin Transactions 2
Дата:
2000
Аннотация:
For the first time a number of terminally protected model peptides (to the pentamer level) of the sterically demanding α-amino acid C<sup>α</sup>-methyl,C<sup>α</sup>-diphenylmethylglycine, (αMe)Dip, in combination with either Ala or Gly residues, have been synthesized (by solution methods) and fully characterized. In a parallel synthesis the corresponding peptides based on the related α-amino acid C<sup>α</sup>-methyl,C<sup>α</sup>-isopropylglycine, (αMe)Val, have also been prepared. The results of a comparative conformational analysis, performed by using FTIR absorption, <sup>1</sup>H NMR, and X-ray diffraction techniques, favour the conclusion that, in contrast to the potent β-turn and 310-helix promoter (αMe)Val, (αMe)Dip may induce either a folded or a fully extended conformation. These findings indicate that, despite the common C<sup>α</sup>-methylated and C<sup>β</sup>-branched features, (αMe)Dip and (αMe)Val are characterized by partially divergent conformational bias.
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