biostudies-literatureHe LDeutsche ForschungsgemeinschaftEuropean Research CouncilNational Natural Science Foundation of ChinaSeventh Framework ProgrammeMax-Planck-GesellschaftGrantov? Agentura Cesk? Republiky10499-10508https://www.ebi.ac.uk/biostudies/studies/S-EPMC10683073biostudies-literatureUnknown14(46)Solvent interactions, particularly hydration, are vital in chemical and biochemical systems. Model systems reveal microscopic details of such interactions. We uncover a specific hydrogen-bonding motif of the biomolecular building block indole (C₈H₇N), tryptophan's chromophore, in water: a strong localized N-H···OH₂ hydrogen bond, alongside unstructured solvent interactions. This insight is revealed from a combined experimental and theoretical analysis of the electronic structure of indole in aqueous solution. We recorded the complete X-ray photoemission and Auger spectrum of aqueous-phase indole, quantitatively explaining all peaks through <i>ab initio</i> modeling. The efficient and accurate technique for modeling valence and core photoemission spectra involves the maximum-overlap method and the nonequilibrium polarizable-continuum model. A two-hole electron-population analysis quantitatively describes the Auger spectra. Core-electron binding energies for nitrogen and carbon highlight the specific interaction with a hydrogen-bonded water molecule at the N-H group and otherwise nonspecific solvent interactions.The journal of physical chemistry lettersSpecific versus Nonspecific Solvent Interactions of a Biomolecule in Water.PMC106830736145079226120188375921-26601XEXC 2056 - 39071599411704147Slavicek PTrinter FTrippel SKupper JBelina MHe LWinter BTomanik LMalerz SfalseSpecific versus Nonspecific Solvent Interactions of a Biomolecule in Water.Solvent interactions, particularly hydration, are vital in chemical and biochemical systems. Model systems reveal microscopic details of such interactions. We uncover a specific hydrogen-bonding motif of the biomolecular building block indole (C₈H₇N), tryptophan's chromophore, in water: a strong localized N-H···OH₂ hydrogen bond, alongside unstructured solvent interactions. This insight is revealed from a combined experimental and theoretical analysis of the electronic structure of indole in aqueous solution. We recorded the complete X-ray photoemission and Auger spectrum of aqueous-phase indole, quantitatively explaining all peaks through <i>ab initio</i> modeling. The efficient and accurate technique for modeling valence and core photoemission spectra involves the maximum-overlap method and the nonequilibrium polarizable-continuum model. A two-hole electron-population analysis quantitatively describes the Auger spectra. Core-electron binding energies for nitrogen and carbon highlight the specific interaction with a hydrogen-bonded water molecule at the N-H group and otherwise nonspecific solvent interactions.2023-01-01T00:00:00Z2023 Nov2025-04-22T08:11:03.35Z2025-02-19T04:44:02.578ZS-EPMC106830733797080710.1021/acs.jpclett.3c01763