The Mouse Eugenol Odorant Receptor: Structural and Functional Plasticity of a Broadly Tuned Odorant Binding Pocket

The giant panda Ailuropoda melanoleuca belongs to the family of Ursidae; however, it is not carnivorous, feeding almost exclusively on bamboo. Being equipped with a typical carnivorous digestive apparatus, the giant panda cannot get enough energy for an active life and spends most of its time digesting food or sleeping. Feeding and mating are both regulated by odors and pheromones; therefore, a better knowledge of olfaction at the molecular level can help in designing strategies for the conservation of this species. In this context, we have identified the odorant-binding protein (OBP) repertoire of the giant panda and mapped the protein expression in nasal mucus and saliva through proteomics. Four OBPs have been identified in nasal mucus, while the other two were not detected in the samples examined. In particular, AimelOBP3 is similar to a subset of OBPs reported as pheromone carriers in the urine of rodents, saliva of the boar, and seminal fluid of the rabbit. We expressed this protein, mapped its binding specificity, and determined its crystal structure. Structural data guided the design and preparation of three protein mutants bearing single-amino acid replacements in the ligand-binding pocket, for which the corresponding binding affinity spectra were measured. We also expressed AimelOBP5, which is markedly different from AimelOBP3 and complementary in its binding spectrum. By comparing our binding data with the structures of bamboo volatiles and those of typical mammalian pheromones, we formulate hypotheses on which may be the most relevant semiochemicals for the giant panda.

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Functions of olfactory receptors are decoded from their sequence

10.1101/2020.01.06.895540 ◽

2020 ◽

Author(s):

Xiaojing Cong ◽

Wenwen Ren ◽

Jody Pacalon ◽

Claire A. de March ◽

Lun Xu ◽

...

Keyword(s):

Machine Learning ◽

Olfactory Receptors ◽

Binding Pocket ◽

Site Directed Mutagenesis ◽

Functional Assay ◽

Machine Learning Approach ◽

Activation Mechanisms ◽

Odorant Binding ◽

G Protein Coupled

AbstractG protein-coupled receptors (GPCRs) conserve common structural folds and activation mechanisms, yet their ligand spectra and functions are highly diversified. This work investigated how the functional variations in olfactory GPCRs (ORs)-the largest GPCR family-are encoded in the primary sequence. With the aid of site-directed mutagenesis and molecular simulations, we built machine learning models to predict OR-ligand pairs as well as basal activity of ORs. In vitro functional assay confirmed 20 new OR-odorant pairs, including 9 orphan ORs. Residues around the odorant-binding pocket dictate the odorant selectivity/specificity of the ORs. Residues that encode the varied basal activities of the ORs were found to mostly surround the conserved motifs as well as the binding pocket. The machine learning approach, which is readily applicable to mammalian OR families, will accelerate OR-odorant mapping and the decoding of combinatorial OR codes for odors.

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Binding Properties of Odorant-Binding Protein 4 of Tirathaba rufivena to Areca catechu Volatiles

Plants ◽

10.3390/plants11020167 ◽

2022 ◽

Vol 11 (2) ◽

pp. 167

Author(s):

Xiang Zhou ◽

Zheng Wang ◽

Guangchao Cui ◽

Zimeng Du ◽

Yunlong Qian ◽

...

Keyword(s):

Binding Protein ◽

Integrated Management ◽

Insect Pest ◽

Binding Pocket ◽

Secretory Protein ◽

Odorant Binding Protein ◽

Host Recognition ◽

Areca Catechu ◽

Fluorescence Binding Assay ◽

Odorant Binding

Odorant-binding proteins (OBPs) play a key role in the olfactory system and are essential for mating and oviposition host selection. Tirathaba rufivena, a serious lepidopterous insect pest of the palm area in recent years, has threatened cultivations of Areca catechu in Hainan. Female-biased odorant-binding protein 4 of T. rufivena (TrufOBP4) expression was hypothesized to participate in the process of oviposition host recognition and localization. In this study, we cloned and analyzed the cDNA sequence of TrufOBP4. The predicted mature protein TrufOBP4 is a small, soluble, secretory protein and belongs to a classic OBP subfamily. Fluorescence binding assay results showed that TrufOBP4 had high binding abilities with the host plant volatiles, octyl methoxycinnamate, dibutyl phthalate, myristic acid and palmitic acid. These four components tend to dock in the same binding pocket based on the molecular docking result. The interactions and contributions of key amino acid residues were also characterized. This research provides evidence that TrufOBP4 might participate in the chemoreception of volatile compounds from inflorescences of A. catechu and can contribute to the integrated management of T. rufivena.

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Direct nuclear magnetic resonance observation of odorant binding to mouse odorant receptor MOR244-3

Analytical Biochemistry ◽

10.1016/j.ab.2016.03.006 ◽

2016 ◽

Vol 502 ◽

pp. 64-72 ◽

Cited By ~ 7

Author(s):

Jessica L. Burger ◽

Kavita M. Jeerage ◽

Thomas J. Bruno

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Odorant Receptor ◽

Odorant Binding ◽

Nuclear Magnetic

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A First Glimpse of the Mexican Fruit Fly Anastrepha ludens (Diptera: Tephritidae) Antenna Morphology and Proteome in Response to a Proteinaceous Attractant

International Journal of Molecular Sciences ◽

10.3390/ijms21218086 ◽

2020 ◽

Vol 21 (21) ◽

pp. 8086

Author(s):

Eliel Ruiz-May ◽

Alma Altúzar-Molina ◽

José M. Elizalde-Contreras ◽

Jiovanny Arellano-de los Santos ◽

Juan Monribot-Villanueva ◽

...

Keyword(s):

Odorant Receptor ◽

Management Strategies ◽

Fruit Fly ◽

Anastrepha Ludens ◽

Mexican Fruit Fly ◽

Odor Perception ◽

Related Proteins ◽

Odorant Binding ◽

Odor Receptors ◽

Specific Odor

Anastrepha ludens is a key pest of mangoes and citrus from Texas to Costa Rica but the mechanisms of odorant perception in this species are poorly understood. Detection of volatiles in insects occurs mainly in the antenna, where molecules penetrate sensillum pores and link to soluble proteins in the hemolymph until reaching specific odor receptors that trigger signal transduction and lead to behavioral responses. Scrutinizing the molecular foundation of odorant perception in A. ludens is necessary to improve biorational management strategies against this pest. After exposing adults of three maturity stages to a proteinaceous attractant, we studied antennal morphology and comparative proteomic profiles using nano-LC-MS/MS with tandem mass tags combined with synchronous precursor selection (SPS)-MS3. Antennas from newly emerged flies exhibited dense agglomerations of olfactory sensory neurons. We discovered 4618 unique proteins in the antennas of A. ludens and identified some associated with odor signaling, including odorant-binding and calcium signaling related proteins, the odorant receptor co-receptor (Orco), and putative odorant-degrading enzymes. Antennas of sexually immature flies exhibited the most upregulation of odor perception proteins compared to mature flies exposed to the attractant. This is the first report where critical molecular players are linked to the odor perception mechanism of A. ludens.

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Full-Length Transcriptome Survey and Expression Analysis of Parasitoid Wasp Chouioia cunea upon Exposure to 1-Dodecene

Scientific Reports ◽

10.1038/s41598-019-54710-0 ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Lina Pan ◽

Meiqi Guo ◽

Xin Jin ◽

Zeyang Sun ◽

Hao Jiang ◽

...

Keyword(s):

Odorant Receptor ◽

Transcriptional Response ◽

Parasitoid Wasp ◽

Invasive Pest ◽

Host Recognition ◽

Hyphantria Cunea ◽

Serine Threonine Kinase ◽

Before And After ◽

Chouioia Cunea ◽

Odorant Binding

AbstractChouioia cunea (Yang) is an endoparasitic wasp which parasitizes pupae and thus plays an important role in the biological control of the fall webworm (Hyphantria cunea Drury), an important quarantine pest in the entire world and a major invasive pest in China. For the purposes of investigating which proteins are involved in the response of C. cunea to 1-Docecene, one of the chemical compounds of pupae of H. cunea with a significant attracting action to mated female C. cunea, 11.5 Gb transcriptome data was sequenced on the PacBio RS II platform from 1-day old C. cunea adults to generate a reference assembly. Afterwards, 46.88 Gb of clean RNA-Seq data were obtained to assess the transcriptional response of these insects before and after the stimulation with 1-Docecene. After removing redundancy using CD-HIT, a sequence structure analysis predicted 29,105 complete coding sequence (CDS) regions, 51,458 single-sequence repeats (SSRs), and 2,375 long non-coding RNAs. Based on the early transcriptome sequencing in our laboratory, we revealed some new sequences corresponding to chemosensory genes such as odorant binding proteins (OBPs), odorant receptor (OR), gustatory receptors(GRs). Results of quantitative real-time PCR experiments revealed that CcOBP7, CcOBP18, CcCSP4, CcOR2, and CcGR18 were up-regulated after 1-Dodecene stimulation. In addition, the expression of 31 genes, including 1 gene related to phospholipid biosynthesis and 2 genes related to transmembrane transport were up-regulated after 1-Dodecene stimulation; meanwhile, the expression of 22 genes, including 5 genes related to protein phosphorylation and protein serine/threonine kinase activity were significantly down-regulated after 1-Dodecene stimulation. These results suggest that the attraction of adult C. cunea to 1-dodecane is associated with the transmembrane signal transduction and dephosphorylation of some proteins. Our findings will provide useful targets for further studies on the molecular mechanism of host recognition in C. cunea.

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The Odorant-Binding Proteins of the Spider Mite Tetranychus urticae

International Journal of Molecular Sciences ◽

10.3390/ijms22136828 ◽

2021 ◽

Vol 22 (13) ◽

pp. 6828

Author(s):

Jiao Zhu ◽

Giovanni Renzone ◽

Simona Arena ◽

Francesca Romana Dani ◽

Harald Paulsen ◽

...

Keyword(s):

Tetranychus Urticae ◽

Spider Mite ◽

Binding Proteins ◽

Three Dimensional ◽

Binding Pocket ◽

Agricultural Pests ◽

Three Dimensional Model ◽

Odorant Binding Proteins ◽

Large Molecules ◽

Odorant Binding

Spider mites are one of the major agricultural pests, feeding on a large variety of plants. As a contribution to understanding chemical communication in these arthropods, we have characterized a recently discovered class of odorant-binding proteins (OBPs) in Tetranychus urticae. As in other species of Chelicerata, the four OBPs of T. urticae contain six conserved cysteines paired in a pattern (C1–C6, C2–C3, C4–C5) differing from that of insect counterparts (C1–C3, C2–C5, C4–C6). Proteomic analysis uncovered a second family of OBPs, including twelve members that are likely to be unique to T. urticae. A three-dimensional model of TurtOBP1, built on the recent X-ray structure of Varroa destructor OBP1, shows protein folding different from that of insect OBPs, although with some common features. Ligand-binding experiments indicated some affinity to coniferyl aldehyde, but specific ligands may still need to be found among very large molecules, as suggested by the size of the binding pocket.

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Extracellular loop 2 of G protein-coupled olfactory receptors is critical for odorant recognition

10.1101/2021.10.26.465980 ◽

2021 ◽

Author(s):

Yiqun Yu ◽

Jody Pacalon ◽

Zhenjie Ma ◽

Lun Xu ◽

Christine Belloir ◽

...

Keyword(s):

G Protein ◽

Drug Targets ◽

Olfactory Receptors ◽

3D Models ◽

Binding Pocket ◽

Site Directed Mutagenesis ◽

Extracellular Loop ◽

Odorant Binding ◽

Loop 2 ◽

G Protein Coupled

G protein-coupled olfactory receptors (ORs) enable us to detect innumerous odorants. They are also ectopically expressed, emerging as attractive drug targets. ORs can be promiscuous or highly specific, which is part of Nature′s strategy for odor discrimination. This work demonstrates that the extracellular loop 2 (ECL2) plays critical roles in OR promiscuity and specificity. Using site-directed mutagenesis and molecular modeling, we constructed 3D OR models in which ECL2 forms a lid of the orthosteric pocket. ECL2 controls the shape and the volume of the odorant-binding pocket, maintains the pocket hydrophobicity and acts as a gatekeeper of odorant binding. The interplay between the specific orthosteric pocket and the variable, less specific ECL2 controls OR specificity and promiscuity. The 3D models enabled virtual screening of new OR agonists and antagonists, exhibiting 78% hit rate in cell assays. This approach can be generalized to structure-based ligand screening for other GPCRs that lack high-resolution 3D structures.

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