Novel extended and branched N-terminal analogs of VIP

Regul Pept. 2006 Nov 15;137(1-2):42-9. doi: 10.1016/j.regpep.2006.02.010. Epub 2006 Sep 8.

Abstract

The effects of vasoactive intestinal peptide (VIP) are primarily mediated through VPAC1 and VPAC2, receptors that are preferentially coupled to adenylate cyclase activation. As a large majority of the potent VIP antagonists have modifications in the N-terminal domain of the peptide, the effect of multiplication of this domain on VIP was examined with the aim of possibly amplifying peptide-receptor (VPAC1) activation. Several VIP analogs were designed and synthesized, each carrying multiplication of the N-terminal domain that was obtained by either linear tandem extension or by parallel branching. Circular dichorism (CD) analysis revealed that these extended/branched peptides maintained an alpha helical structure in organic environment, similar to VIP. A specific branched VIP analog was found to be slightly more potent towards VPAC1-related cAMP production as compared to VIP. This analog could have potential therapeutic value in several disorders, similar to VIP. Two branched N-terminal VIP sequences demonstrated superior receptor binding and activation as compared to two N-terminals in tandem. The results suggest that correct alignment of the VIP N-terminal region is important for receptor binding and activation. However, increased receptor binding was not directly associated with increased cAMP production suggesting steric dynamic interactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Circular Dichroism
  • Cyclic AMP / metabolism
  • HT29 Cells
  • Humans
  • Molecular Sequence Data
  • Vasoactive Intestinal Peptide / analogs & derivatives*
  • Vasoactive Intestinal Peptide / chemistry

Substances

  • Vasoactive Intestinal Peptide
  • Cyclic AMP