1d6g
From Proteopedia
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MOLECULAR COMPLEX OF CHOLECYSTOKININ-8 AND N-TERMINUS OF THE CHOLECYSTOKININ A RECEPTOR BY NMR SPECTROSCOPY
Overview
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.
About this Structure
1D6G is a Single protein structure of sequence from [1] with NH2 as ligand. Full crystallographic information is available from OCA.
Reference
Molecular complex of cholecystokinin-8 and N-terminus of the cholecystokinin A receptor by NMR spectroscopy., Pellegrini M, Mierke DF, Biochemistry. 1999 Nov 9;38(45):14775-83. PMID:10555959
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