Characterization of the new photoaffinity probe (Bz2-K24)-VIP.
Site-directed mutagenesis and molecular modeling demonstrated that the N-terminal ectodomain of the VPAC1 receptor is a major site of vasoactive intestinal peptide (VIP) binding. Previous studies with the [Bpa6]-VIP and [Bpa22]-VIP probes (substitution with the photoactivable Bpa for the residues 6 and 22 in VIP) showed spatial approximation between the amino acids 6 and 22 of VIP and the 104-108 and 109-119 sequences within the N-terminal ectodomain of the receptor, respectively. Here, we characterize the new probe (Bz2-K24)-VIP (substitution with the photoreactive Bz2-K for the residue 24 in VIP). After photolabeling and sequential digestions of the receptor, the 121-133 sequence of the N-terminal ectodomain was identified as the site of interaction. The N-terminal ectodomain of the VPAC1 receptor is therefore an affinity trap for the central part of VIP, at least between residues 6 and 24.
Tan
Yossan-Var
YV
INSERM U773, Faculté de Médecine Bichat, 16 rue Henri Huchard, 75018 Paris, France.
Couvineau
Alain
A
Lacapere
Jean Jacques
JJ
Laburthe
Marc
M
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D006801:Humans; D019920:Photoaffinity Labels / Q000032:analysis* / Q000737:chemistry*; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism
C513613:(Bz2-K24)-vasoactive intestinal peptide; D019920:Photoaffinity Labels; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; D014660:Vasoactive Intestinal Peptide; D000262:Adenylyl Cyclases