title: NMR structural study of the intracellular loop 3 of the serotonin 5-HT(1A) receptor and its interaction with calmodulin.
abstract: The serotonin (5-HT(1A)) receptor, a G-protein-coupled receptor (GPCR), plays important roles in serotonergic signaling in the central nervous system. The third intracellular loop (ICL3) of the 5-HT(1A) receptor has been shown to be important for the regulation of this receptor through interactions with proteins such as G-proteins and calmodulin. In this study, the ICL3 of 5-HT(1A) receptor was expressed in E. coli and purified. Gel filtration and mass spectrometry were used to confirm the molecular weight of the purified ICL3. Secondary structure analysis using circular dichroism (CD) demonstrated the presence of α-helical structures. Backbone assignment of ICL3 was achieved using three-dimensional experiments. A chemical shift index and Talos+ analysis showed that residues E326 to R339 form α-helical structure. Residues G256 to S269 of ICL3 were shown to be a novel region that has a molecular interaction with calmodulin in titration assays. Peptide derived from the ICL3 containing residues from G256 to S269 also showed molecular interaction with calmodulin.
authors.affiliation: Experimental Therapeutics Centre, Agency for Science, Technology and Research(A*STAR), Singapore 138669, Singapore.
authors.forename: Angela Shuyi
authors.initials: AS
authors.lastname: Chen
authors.forename: Young Mee
authors.initials: YM
authors.lastname: Kim
authors.forename: Shovanlal
authors.initials: S
authors.lastname: Gayen
authors.forename: Qiwei
authors.initials: Q
authors.lastname: Huang
authors.forename: Manfred
authors.initials: M
authors.lastname: Raida
authors.forename: Congbao
authors.initials: C
authors.lastname: Kang
mesh_terms: D000595:Amino Acid Sequence; D002147:Calmodulin / Q000737:chemistry*; D002850:Chromatography, Gel / Q000379:methods; D002852:Chromatography, Ion Exchange / Q000379:methods; D002942:Circular Dichroism; D003001:Cloning, Molecular; D019295:Computational Biology / Q000379:methods; D004926:Escherichia coli / Q000378:metabolism*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010455:Peptides / Q000737:chemistry; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D044282:Receptor, Serotonin, 5-HT1A / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D012701:Serotonin / Q000737:chemistry
chemical_list: D002147:Calmodulin; D010455:Peptides; D044282:Receptor, Serotonin, 5-HT1A; D012701:Serotonin