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Relationships between conformational and vibrational features of tryptophan characteristic Raman markers.
Hernández, Belén; Coïc, Yves-Marie; Kruglik, Sergei G; Sanchez-Cortes, Santiago; Ghomi, Mahmoud.
Afiliação
  • Hernández B; LVTS, INSERM U1148. 74 rue Marcel Cachin. 93017 Bobigny Cédex France.
  • Coïc YM; Institut Pasteur, Université Paris Cité, CNRS UMR3523, Unité de Chimie des Biomolécules, F-75015 Paris, France.
  • Kruglik SG; Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Jean-Perrin, 4 Place Jussieu, 75005 Paris, France.
  • Sanchez-Cortes S; Instituto de Estructura de la Materia, IEM-CSIC, Serrano 121, 28006 Madrid, Spain.
  • Ghomi M; Instituto de Estructura de la Materia, IEM-CSIC, Serrano 121, 28006 Madrid, Spain. Electronic address: mahmoud.ghomi@univ-paris13.fr.
Spectrochim Acta A Mol Biomol Spectrosc ; 316: 124377, 2024 Aug 05.
Article em En | MEDLINE | ID: mdl-38701580
ABSTRACT
Tryptophan (Trp) residue provides characteristic vibrational markers to the middle wavenumber spectral region of the Raman spectra recorded from peptides and proteins. In this report, we were particularly interested in eight Trp Raman markers, referred to as Wi (i = 1,…,8). All responsible for pronounced Raman lines, these markers originate from indole moiety, a bicyclic conjugated segment involved in the Trp structure. Numerous investigations have previously attempted to relate the variations observed in the spectral features of these markers to the environmental changes of Trp residues. To emphasize the most important points we can mention (i) the variations in the Raman profile of W4 (∼1360 cm-1) and W5 (∼1340 cm-1), frequently observed as a doublet with variable intensity ratio. These two markers were thought to result from a Fermi-resonance effect between certain planar and nonplanar modes; (ii) the changes observed in the wavenumbers and relative intensities of W4, W7 (∼880 cm-1) and W8 (∼760 cm-1) were supposed to be related to the accessibility of Trp to surrounding water molecules; and (iii) the wavenumber fluctuations of W3 (∼1550 cm-1), taken as a Trp side chain orientational marker. However, some ambiguities still exist regarding the interpretation of these markers, needing further clarification. Herein, upon a joint experimental and theoretical analysis based on a multiconformational approach, attention was paid to the relationships between structural and vibrational features of three indole-containing compounds with increasing structural complexity, i.e., skatole (3-methylindole), tryptophan, and tripeptide Gly-Trp-Gly. This study clearly shows that the existing assignments given to certain Trp Raman markers should be reconsidered, especially those based on the Fermi-resonance origin of W4-W5 (∼1360-1340 cm-1) doublet, as well as the purely environmental dependence of W7 and W8 markers.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Análise Espectral Raman / Triptofano / Vibração Idioma: En Ano de publicação: 2024 Tipo de documento: Article

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Análise Espectral Raman / Triptofano / Vibração Idioma: En Ano de publicação: 2024 Tipo de documento: Article