title: Structural features of the C-terminus from the human neurokinin-1 receptor.
abstract: The neurokinin-1 receptor (NK1R) is a G-protein coupled receptor found in the central and peripheral nervous systems of vertebrates, and is responsible for many physiological processes. The C-terminus domain seems to be essential for coupling to the corresponding G-protein and β-arrestin, and is important for receptor desensitization, internalization and recycling. We have focused our study on expression of the human NK1R (hNK1R) C-terminus in Escherichia coli, and its purification and characterization, in order to elucidate its structural properties. CD and Fourier transform infrared spectroscopy showed that the hNK1R C-terminus, rather than having a random structure, has well-defined secondary-structure patterns. The presence of three tyrosine residues in the primary sequence of the hNK1R C-terminus facilitated the use of UV and fluorescence spectroscopy techniques which revealed tyrosine fluorescence and UV absorption at anomalous wavelengths. In their entirety, the results show that the hNK1R C-terminus has clearly defined secondary (25% α-helix, 27% unordered structure and 48% β-sheets and β-turns) and tertiary structures which, it is believed, are tightly related to its multiple functions.
authors.affiliation: Unitat de Biofísica, Departament de Bioquímica i de Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, Spain.
authors.forename: Mikhail
authors.initials: M
authors.lastname: Orel
authors.forename: Esteve
authors.initials: E
authors.lastname: Padrós
authors.forename: Joan
authors.initials: J
authors.lastname: Manyosa
mesh_terms: D000595:Amino Acid Sequence; D015153:Blotting, Western; D002942:Circular Dichroism; D006801:Humans; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D018040:Receptors, Neurokinin-1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D014443:Tyrosine / Q000378:metabolism
chemical_list: D018040:Receptors, Neurokinin-1; D014443:Tyrosine