Conformational effects of the non-natural alpha-methylserine on small peptides and glycopeptides

  1. Fernández-Tejada, A. 1
  2. Corzana, F. 1
  3. Busto, J.H. 1
  4. Avenoza, A. 1
  5. Peregrina, J.M. 1
  1. 1 Universidad de La Rioja
    info

    Universidad de La Rioja

    Logroño, España

    ROR https://ror.org/0553yr311

Revista:
Journal of Organic Chemistry

ISSN: 0022-3263

Año de publicación: 2009

Volumen: 74

Número: 24

Páginas: 9305-9313

Tipo: Artículo

DOI: 10.1021/JO901988W PMID: 19924838 SCOPUS: 2-s2.0-73149103487 WoS: WOS:000272462100007 GOOGLE SCHOLAR

Otras publicaciones en: Journal of Organic Chemistry

Resumen

(Chemical Equation Presented) The synthesis and the conformational analysis in aqueous solution of a peptide and a glycopeptide containing the sequence threonine-alanine-alanine (Thr-Ala-Ala) are reported. Furthermore, the threonine residue has been replaced by the quaternary amino acid α-methylserine (MeSer) and their corresponding non-natural peptide and glycopeptide are also studied. The conformational analysis in aqueous solution combines NOEs and coupling constants data with Molecular Dynamics (MD) simulations with time-averaged restraints. The study reveals that the β-O-glycosylation produces a remarkable and completely different effect on the backbone of the peptide derived from Thr and MeSer. In the former, the β-O-glycosylation is responsible for the experimentally observed shift from extended conformations (peptide) to folded ones (glycopeptide). In contrast, the β-O-glycosylation of the MeSer-containing peptide, which clearly shows two main conformations in aqueous solution [extended ones (70%) and β-turn (30%)], causes a high degree of flexibility for the backbone. © 2009 American Chemical Society.