1D6G image
Entry Detail
PDB ID:
1D6G
Title:
MOLECULAR COMPLEX OF CHOLECYSTOKININ-8 AND N-TERMINUS OF THE CHOLECYSTOKININ A RECEPTOR BY NMR SPECTROSCOPY
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
1999-10-13
Release Date:
1999-11-17
Method Details:
Experimental Method:
Conformers Calculated:
90
Conformers Submitted:
1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:cholecystokinin type a receptor
Chain IDs:A
Chain Length:47
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:cholecystokinin-8
Chain IDs:B
Chain Length:9
Number of Molecules:1
Biological Source:Homo sapiens
Ligand Molecules
Primary Citation
Molecular complex of cholecystokinin-8 and N-terminus of the cholecystokinin A receptor by NMR spectroscopy.
Biochemistry 38 14775 14783 (1999)
PMID: 10555959 DOI: 10.1021/bi991272l

Abstact

The bimolecular complex of the C-terminal octapeptide of cholecystokinin, CCK-8, with the N-terminus of the CCK(A)-receptor, CCK(A)-R(1-47), has been structurally characterized by high-resolution NMR and computational refinement. The conformation of CCK(A)-R(1-47), within the lipid environment used for the spectroscopic studies, consists of a well-defined alpha-helix (residues 3-9) followed by a beta-sheet stabilized by a disulfide linkage between C18 and C29, leading to the first transmembrane alpha-helix (TM1). Titration of CCK(A)-R(1-47) with CCK-8 specifically affects the NMR signals of W39 of the receptor, in a saturable fashion. This association is specific for CCK-8; no association was observed upon titration of CCK(A)-R(1-47) with other peptide hormones. The ligand/receptor complex was characterized by intermolecular NOEs between Tyr(27) and Met(28) of CCK-8 and W39 of CCK(A)-R(1-47). These findings suggest that CCK-8 binds to CCK(A) with the C-terminus within the seven-helical bundle and the N-terminus of the ligand, projecting out between TM1 and TM7, forming specific interactions with the N-terminus of the CCK(A) receptor. This mode of ligand binding, consistent with published mutagenesis studies, requires variation of the interpretation of recent findings from photoaffinity cross-linking studies.

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Primary Citation of related structures