Extracellular domains of the neurokinin-1 receptor: structural characterization and interactions with substance P.
The technical difficulties associated with the structure determination of membrane proteins have limited the structural information available for the ligand binding to G-protein coupled receptors (GPCRs). Here, we describe a reductionist approach to GPCR structure determination in which the extracellular domains of the receptor are examined by high-resolution NMR in the presence of a membrane mimetic. The resulting structural features are then incorporated into a molecular model of the receptor, utilizing the x-ray structure of rhodopsin to generate the topological orientation of the transmembrane helices. The results of our study of the neurokinin-1 receptor (NK-1R) and its interactions with substance P (SP) are detailed here. The structure of the N-terminus, NK-1R(1-39), and of the third extracellular loop, NK-1R(264-290), in the presence of dodecylphosphocholine micelles is described. Our findings provide a structural basis for the interpretation of the results from other methods including mutagenesis, fluorescence, and photoaffinity labeling experiments, resulting in an experimentally based, high-resolution model of SP binding to NK-1R.
Ulfers
Amy L
AL
Department of Molecular Pharmacology, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA.
Piserchio
Andrea
A
Mierke
Dale F
DF
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D005110:Extracellular Space / Q000737:chemistry; D019204:GTP-Binding Proteins / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010446:Peptide Fragments / Q000737:chemistry; D017433:Protein Structure, Secondary; D051381:Rats; D018040:Receptors, Neurokinin-1 / Q000737:chemistry* / Q000378:metabolism*; D013373:Substance P / Q000378:metabolism*
D010446:Peptide Fragments; D018040:Receptors, Neurokinin-1; D013373:Substance P; D019204:GTP-Binding Proteins