Interaction between ghrelin and the ghrelin receptor (GHS-R1a), a NMR study using living cells.
The study of the interaction of ghrelin (1), the endogenous ligand for the GH secretagogues receptor (GHS-R1a), and des-acyl ghrelin (2) with the GHS-R1a by NMR using living cells is presented, using GHS-R1a stably transfected cell lines (CHO and HEK 293) and wild type cells. Therefore, the interaction of 1 and 2 with the GHS-R1a receptor has been performed using quasi-physiological conditions. Ghrelin (1), showed a higher number of residues affected by chemical shift perturbation (CSP) or chemical shift exchange (CSE) effects: Ser3, Phe4, Leu5, Val12, Gln13/Gln14, Lys16/Lys19, Glu17 and Lys24 were much more affected in 1 than in des-acyl ghrelin (2). The chemical shift index CSI values indicated the presence of a possible alpha-helical region between Glu8 and Lys20 for ghrelin (1). After analysing the NMR data, two possible structures have arisen, which present different proline rotamers: the EEZE and the EZEZ conformers, at positions Pro7, Pro21, Pro22 and Pro27, respectively, keeping a left-handed alpha-helix from Glu8 to Lys20. These experimental evidences might imply that the GHS-R1a receptor is acting as a prolyl-cis/trans isomerase.
Unidade de Resonancia Magnética, RIAIDT, Universidad de Santiago de Compostela, Santiago de Compostela, Spain.
Manuel
M
Martín-Pastor
Antonia
A
De Capua
Carlos J P
CJ
Alvarez
M Dolores
MD
Díaz-Hernández
Jesús
J
Jiménez-Barbero
Felipe F
FF
Casanueva
Yolanda
Y
Pazos
D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D054439:Ghrelin / Q000737:chemistry*; D006801:Humans; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D054440:Receptors, Ghrelin / Q000737:chemistry*
D054439:Ghrelin; D054440:Receptors, Ghrelin