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Spatial Approximation between the C‐Terminus of VIP and the N‐Terminal Ectodomain of the VPAC1 Receptor
Author(s) -
CERAUDO E.,
TAN Y.V.,
COUVINEAU A.,
LACAPERE J.J.,
LABURTHE MARK
Publication year - 2006
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1196/annals.1317.009
Subject(s) - ectodomain , receptor , terminal (telecommunication) , chemistry , microbiology and biotechnology , biochemistry , biophysics , biology , computer science , telecommunications
Vasoactive intestinal peptide (VIP) exerts many biological functions through interaction with the VPAC1 receptor, a class II G protein–coupled receptor. Photoaffinity labeling studies associated with receptor mapping and three‐dimensional molecular modeling demonstrated that the central part of VIP (6–24) interacts with the N‐terminal ectodomain of VPAC1 receptor.However, the domain of the VPAC1 receptor interacting with the C‐terminus of VIP is still unknown. A photoaffinity probe, Bpa 28 ‐VIP, was synthetized by substitution of amidated Asn 28 of VIP by amidated photoreactive para ‐benzoyl‐L‐Phe (Bpa). Bpa 28 ‐VIP was shown to be a hVPAC1 receptor agonist in CHO cells expressing the recombinant VPAC1 receptor. After obtaining a covalent 125 I‐[Bpa 28 ‐VIP]/hVPAC1 complex, it was cleaved by CNBr, PNGase F, and endopeptidase Glu‐C and the cleavage products were analyzed by electrophoresis. The data demonstrated that 125 I‐[Bpa 28 ‐VIP] was covalently bonded to the 121–133 fragment within the N‐terminal ectodomain of the receptor. This fragment is adjacent to those covalently attached to the central part (6–24) of VIP.