5EL2

Crystal structure of Odorant Binding Protein 1 from Anopheles gambiae (AgamOBP1) with Icaridin (butan-2-yl 2-(2-hydroxyethyl)piperidine-1-carboxylate)

Summary for 5EL2

• Entry DOI: 10.2210/pdb5el2/pdb
• Descriptor: AGAP003309-PA, MAGNESIUM ION, Icaridin, ... (4 entities in total)
• Functional Keywords: transport protein, insect odorant binding protein, obp1, agamobp1, olfaction, icaridin, butan-2-yl 2-(2-hydroxyethyl)piperidine-1-carboxylate
• Biological source: Anopheles gambiae (African malaria mosquito)
• Total number of polymer chains: 2
• Total formula weight: 30036.81

Authors

Drakou, C.E.,Tsitsanou, K.E.,Zographos, S.E. (deposition date: 2015-11-04, release date: 2016-08-31, Last modification date: 2024-01-10)

Primary citation

Drakou, C.E.,Tsitsanou, K.E.,Potamitis, C.,Fessas, D.,Zervou, M.,Zographos, S.E.
The crystal structure of the AgamOBP1Icaridin complex reveals alternative binding modes and stereo-selective repellent recognition.
Cell. Mol. Life Sci., 74:319-338, 2017

PubMed Abstract: Anopheles gambiae Odorant Binding Protein 1 in complex with the most widely used insect repellent DEET, was the first reported crystal structure of an olfactory macromolecule with a repellent, and paved the way for OBP1-structure-based approaches for discovery of new host-seeking disruptors. In this work, we performed STD-NMR experiments to directly monitor and verify the formation of a complex between AgamOBP1 and Icaridin, an efficient DEET alternative. Furthermore, Isothermal Titration Calorimetry experiments provided evidence for two Icaridin-binding sites with different affinities (Kd = 0.034 and 0.714 mM) and thermodynamic profiles of ligand binding. To elucidate the binding mode of Icaridin, the crystal structure of AgamOBP1•Icaridin complex was determined at 1.75 Å resolution. We found that Icaridin binds to the DEET-binding site in two distinct orientations and also to a novel binding site located at the C-terminal region. Importantly, only the most active 1R,2S-isomer of Icaridin's equimolar diastereoisomeric mixture binds to the AgamOBP1 crystal, providing structural evidence for the possible contribution of OBP1 to the stereoselectivity of Icaridin perception in mosquitoes. Structural analysis revealed two ensembles of conformations differing mainly in spatial arrangement of their sec-butyl moieties. Moreover, structural comparison with DEET indicates a common recognition mechanism for these structurally related repellents. Ligand interactions with both sites and binding modes were further confirmed by 2D H-N HSQC NMR spectroscopy. The identification of a novel repellent-binding site in AgamOBP1 and the observed structural conservation and stereoselectivity of its DEET/Icaridin-binding sites open new perspectives for the OBP1-structure-based discovery of next-generation insect repellents.

PubMed: 27535661
DOI: 10.1007/s00018-016-2335-6

Experimental method

X-RAY DIFFRACTION (1.75 Å)