Assessment of the conformational features of vasoactive intestinal peptide in solution by limited proteolysis experiments

Paola Stiuso, Anna Marabotti, Angelo Facchiano, Marilena Lepretti, Alessandra Dicitore, Pasquale Ferranti, Maria Cartenì

Research output: Contribution to journalArticlepeer-review

Abstract

The structural features of vasoactive intestinal peptide (VIP) and of its Gln16-diaminopropane derivative (VIP-DAP) in solution were investigated by limited proteolysis experiments with trypsin and thermolysin. The proteolysis of the native peptide by both proteinases takes place near the residues in positions 12 and 21/22, suggesting that these amino acids are embedded in segments more flexible than the rest of the molecule. VIP-DAP appears to be more resistant to the proteolytic attack of trypsin, indicating that the derivatization in position 16 is able to stabilize the structure of the peptide. Moreover, the analysis of the mass spectra of the proteolytic mixtures supports the evidence that the derivatization is also able to protect Met 17 against oxidation. From these data it can be concluded that VIP in solution under physiological conditions is characterized by the presence of segments with secondary structure, linked together by "hinge" regions that confer flexibility to the peptide, whereas VIP-DAP is embedded in a more rigid conformation, more suitable to receptor interaction.

Original languageEnglish
Pages (from-to)110-119
Number of pages10
JournalBiopolymers
Volume81
Issue number2
DOIs
Publication statusPublished - Feb 5 2006

Keywords

  • Conformational analysis
  • Limited proteolysis
  • Mass spectrometry
  • Vasoactive intestinal peptide
  • Vasoactive intestinal peptide analogues

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Biophysics

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