The vasoactive intestinal peptide (VIP) alpha-Helix up to C terminus interacts with the N-terminal ectodomain of the human VIP/Pituitary adenylate cyclase-activating peptide 1 receptor: photoaffinity, molecular modeling, and dynamics.
The neuropeptide vasoactive intestinal peptide (VIP) strongly impacts on human pathophysiology and does so through interaction with class II G protein-coupled receptors. We characterized the C terminus-binding site of VIP in the N-terminal ectodomain (N-ted) of the human VPAC1 receptor: 1) The probe [(125)I-Bpa(28)]VIP in which the C-terminal residue (Asn(28)) is substituted by a photoreactive p-benzoyl-l-Phe (Bpa) was used to photolabel the receptor. After receptor cleavage and Edman sequencing, it was shown that Asn(28) of VIP is in contact with Lys(127) in the receptor N-ted. Taking into account previous data, it follows that the C-terminal and central parts of VIP from Asn(28) to Phe(6) lie in the N-ted. 2) A three-dimensional model of the N-ted was constructed, the fold being identified as a Sushi domain with two antiparallel beta-sheets and three disulfide bonds. The nuclear magnetic resonance structure of VIP was then docked into this model by taking into account the constraint provided by photoaffinity experiments with [(125)I-Bpa(28)]VIP. It appeared that VIP runs parallel to the beta3-beta4 antiparallel sheets. 3) We performed molecular dynamic simulations over 14 nsec of the complex between VIP and receptor N-ted and the free N-ted. The structural model of the free N-ted is stable, and VIP tends to further stabilize the N-ted structure more especially in the loops connecting the beta-sheets. These structural studies provide a detailed molecular understanding of the VIP-receptor interaction.
Ceraudo
Emilie
E
Institut National de la Santé et de la Recherche Médicale Unité 773, Centre de Recherche Biomédicale Bichat-Beaujon, CRB3, Faculté de Médecine Xavier Bichat, 75018, Paris, France.
Murail
Samuel
S
Tan
Yossan-Var
YV
Lacapère
Jean-Jacques
JJ
Neumann
Jean-Michel
JM
Couvineau
Alain
A
Laburthe
Marc
M
D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D003198:Computer Simulation; D006224:Cricetinae; D003412:Cricetulus; D006801:Humans; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; D014660:Vasoactive Intestinal Peptide