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）：哺乳动物使用几种化学感受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，不同群体的化学感受细胞的刺激选择性的差异在很大程度上反映了其中表达的化学感受受体（CR）的配体选择性和敏感性的差异。难以获得大量的受体蛋白适合生化或结构分析，以及配体是已知的CR的数量少，阻碍了努力的基础上的配体特异性的特点。一组CR，T1 R味觉受体，提供了独特的优势，这将允许第一次系统分析CR结构/功能关系如何影响化学感受细胞群检测和区分生理相关配体的能力。我们将利用T1 Rs对甜味配体的敏感性，以及细胞外N-末端配体结合结构域的生物化学纯化和结构表征，建立不同T1 Rs在甜味刺激检测中的作用。目标1：在存在和不存在配体的情况下，T1 R配体结合口袋的结构将通过T1 R N-末端结构域的圆二色谱分光光度法和X射线晶体学的组合来解决。目标二：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中的基因靶向在T1 R N-末端结构域的配体结合口袋中引入靶向突变。将使用等温滴定量热法测量配体结合动力学的变化，而T1 R缺失或突变对味觉功能的影响将通过触觉接近行为任务来测定，其中将确定靶向小鼠对甜味刺激的敏感性。总之，这些研究将提供化学感受受体及其配体之间相互作用的第一次深入的结构和定量分析，并将提供重要的新见解，了解个体味觉受体如何有助于检测和区分对健康和生存至关重要的食物线索。

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