Cys-Xxx-Ser-Xxx-Pro-Cys (Xxx= any amino acid but Pro) is the most common sequence present in naturally
occurring peptides and proteins glycosylated with β-O-glucose (β-O-Glc). Taking into account the lack of studies concerning
the spatial disposition of this sequence, we have synthesized and analyzed, in aqueous solution, the conformational
behavior of peptides and a glycopeptide derived from the particular fragment Cys-Ala-Ser-Ser-Pro-Cys. This sequence
is found in the crystal structure of the complex of blood coagulation factor VIIa with soluble tissue factor. Our
studies, based on the use of NOESY experiments in combination with molecular dynamics (MD) simulations, indicate
that for this particular fragment, initially characterized by a type I β-turn motif, the glycosylation with β-O-Glc forces the
peptide backbone into an extended conformation. This conformation is stabilized by the presence of both hydrogen bonds
and water pockets between the peptide and the sugar moieties.
Keywords: β-O-glucosylation, Conformational analysis, Molecular dynamics, Nuclear magnetic resonance.
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