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Updated: Sep 17, 2025

Submillisecond Conformational Changes in Proteins Resolved by Photothermal Beam Deflection
Published on: February 18, 2014
Hydrogen-bond-assisted conformational selection of picaridin in the gas phase
Otger Crehuet1,2, Andrea Vázquez1,2, Francisco J Basterretxea1
1Departamento de Química Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU), Leioa, 48940, Spain. pablo.pinacho@uva.es.
Abstract:
Understanding the intrinsic shape of bioactive molecules such as picaridin is key to elucidating their mode of action. In this work, we characterize the gas-phase conformational landscape of picaridin, a flexible chiral repellent with two stereocenters. Broadband rotational spectroscopy combined with quantum chemical calculations reveals a single dominant conformer per enantiomeric pair, both stabilized by internal O-H⋯O hydrogen bonds. These intramolecular interactions induce conformational locking, constraining the hydroxyethyl chain and favouring a compact geometry. Non-covalent interaction analysis further confirms that dispersion and hydrogen bonding play a central role in conformational selection under isolated conditions.
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