Chemosensory receptors and the basis of specificity

化学感应受体和特异性的基础

• 批准号: 7903521
• 负责人: Steven D Munger
• 金额: $ 12.72万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-14 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7903521
• 关键词: Address; Affinity; Affinity Chromatography; Amino Acids; Behavioral; Behavioral Assay; Binding; Biochemical; Biological Assay; Calorimetry; Cells; Chemicals; Circular Dichroism; Classification; Code; Complex; Complex Mixtures; Cues; Data; Detection; Discrimination; Eating; Environment; Esthesia; Family; Food; G-Protein-Coupled Receptors; GTP-Binding Proteins; Gene Targeting; Goals; Health; In Vitro; Individual; Kinetics; Ligand Binding; Ligand Binding Domain; Ligands; Light; Mammals; Measures; Membrane Proteins; Mus; Mutation; N-terminal; Neurotransmitters; Odors; Opsin; Pheromone; Pheromone Receptors; Photons; Population; Psychophysiology; Retinal Cone; Role; Sensory; Solutions; Specificity; Spectrophotometry; Stimulus; Structure; Structure-Activity Relationship; System; T1R receptor; Taste Perception; Tertiary Protein Structure; Titrations; Variant; Visual system structure; X-Ray Crystallography; base; cell type; extracellular; innovation; insight; member; nutrition; olfactory receptor; protein expression; receptor; receptor structure function; response; sensory system; stimulus sensitivity; sweet receptor; sweet taste perception

DESCRIPTION (provided by applicant): Mammals use several chemosensory systems to detect and encode their chemical environment. How these systems discriminate relevant chemical cues is a major unresolved question. We hypothesize that differences in the stimulus selectivity of different populations of chemosensory cells largely reflects differences in the ligand selectivity and sensitivity of the chemosensory receptors (CRs) expressed therein. Difficulties in obtaining large amounts of receptor protein suitable for biochemical or structural analysis, as well as the small number of CRs for which ligands are known, has hampered efforts to characterize the basis of ligand specificity. One group of CRs, the T1R taste receptors, offers unique advantages that will permit the first systematic analysis of how CR structure/function relationships impact the ability of a chemosensory cell population to detect and discriminate physiologically relevant ligands. We will take advantage of the demonstrated sensitivity of T 1Rs for sweet-tasting ligands, and an extracellular N-terminal ligand-binding domain amenable to biochemical purification and structural characterization, to establish the role of different T1Rs in the detection of sweet tasting stimuli. Aim 1: The structure of the T1R ligand-binding pockets, in the presence and absence of ligands, will be solved by a combination of circular dichroism spectrophotometry and X-ray crystallography of T1R N-terminal domains. Aim 2: To determine the specific contributions of ligand binding to taste function, targeted mutations will be introduced in the ligand-binding pocket of T1R N-terminal domains both in vitro and by gene targeting in mice. Changes in ligand binding kinetics will be measured using isothermal titration calorimetry, while the effects of T1R deletion or mutation on taste function will be assayed by brief-access behavioral tasks where the sensitivity of targeted mice to sweet stimuli will be determined. Together, these studies will provide the first in-depth structural and quantitative analyses of the interactions between chemosensory receptors and their ligands, and will offer important new insights into how individual taste receptors contribute to the detection and discrimination of food cues critical for health and survival.

描述（由申请人提供）：哺乳动物使用多种化学感应系统来检测和编码其化学环境。这些系统如何区分相关的化学线索是一个尚未解决的主要问题。我们假设不同群体的化学感应细胞的刺激选择性的差异很大程度上反映了其中表达的化学感应受体（CR）的配体选择性和敏感性的差异。获得大量适合生化或结构分析的受体蛋白的困难，以及已知配体的少量CR，阻碍了表征配体特异性基础的努力。一组 CR，即 T1R 味觉受体，具有独特的优势，可以首次系统分析 CR 结构/功能关系如何影响化学感应细胞群检测和区分生理相关配体的能力。我们将利用 T 1R 对甜味配体的敏感性，以及适合生化纯化和结构表征的细胞外 N 末端配体结合域，来确定不同 T1R 在检测甜味刺激中的作用。目标 1：在存在和不存在配体的情况下，T1R 配体结合口袋的结构将通过圆二色分光光度法和 T1R N 端结构域的 X 射线晶体学相结合来解析。目标 2：为了确定配体结合对味觉功能的具体贡献，将在体外和通过小鼠基因靶向在 T1R N 末端结构域的配体结合口袋中引入靶向突变。配体结合动力学的变化将使用等温滴定量热法进行测量，而 T1R 缺失或突变对味觉功能的影响将通过简短的行为任务进行分析，其中将确定目标小鼠对甜味刺激的敏感性。总之，这些研究将对化学感应受体及其配体之间的相互作用提供首次深入的结构和定量分析，并将为个体味觉受体如何有助于检测和辨别对健康和生存至关重要的食物线索提供重要的新见解。

项目成果

Olfactory receptors: G protein-coupled receptors and beyond.

• DOI: 10.1111/j.1471-4159.2009.06085.x
• 发表时间: 2009-06
• 期刊: Journal of neurochemistry
• 影响因子: 4.7
• 作者: Spehr M;Munger SD
• 通讯作者: Munger SD

Variation in the gene TAS2R38 is associated with the eating behavior disinhibition in Old Order Amish women.

• DOI: 10.1016/j.appet.2009.09.011
• 发表时间: 2010-02
• 期刊: APPETITE
• 影响因子: 5.4
• 作者: Dotson, Cedrick D.;Shaw, Hillary L.;Mitchell, Braxton D.;Munger, Steven D.;Steinle, Nanette I.
• 通讯作者: Steinle, Nanette I.

Reduced sweetness of a monellin (MNEI) mutant results from increased protein flexibility and disruption of a distant poly-(L-proline) II helix.

• DOI: 10.1093/chemse/bjr007
• 发表时间: 2011-06
• 期刊: Chemical senses
• 影响因子: 3.5
• 作者: C. Templeton;Saeideh Ostovar pour;J. Hobbs;E. Blanch;S. Munger;G. Conn

Bitter taste receptors influence glucose homeostasis.

• DOI: 10.1371/journal.pone.0003974
• 发表时间: 2008
• 期刊: PloS one
• 影响因子: 3.7
• 作者: Dotson CD;Zhang L;Xu H;Shin YK;Vigues S;Ott SH;Elson AE;Choi HJ;Shaw H;Egan JM;Mitchell BD;Li X;Steinle NI;Munger SD
• 通讯作者: Munger SD