Wydział Chemii

E. Podstawka

Henryk Kozłowski

L. M. Proniewicz

2006

Journal of Raman Spectroscopy

37

574-584

doi.org/10.1002/jrs.1433

Naukowa

Angielski

Artykuł

n this study, Fourier-transform Raman (FT-RS) and infrared (FT-IR) absorption spectroscopies were employed to characterize the molecular structures of L-Ala-(3,4-dimethoxy)-L-Phe-PO₃H₂ (A) and L-Ala-(3,4-dimethoxy)-(des-CH₂)-L-Phe-PO₃H₂ (B) phosphonodipeptides, where L-Phe denotes L-phenylalanine and L-Ala, L-alanine. The vibrational band assignments have been proposed. In order to determine the structures of these dimethoxyphenyl-substituted phosphonodipeptides adsorbed on a colloidal silver surface, surface enhanced Raman spectra (SERS) were measured. The analysis of SERS band intensities showed that these dimethoxyphenyl-substituted phosphonodipeptides directly interacted with the silver surface through the aromatic ring of Phe that adopted an orientation almost perpendicular to the silver surface. We also showed that intense enhancement of the ν_as(NH₂), δ_as(PO₃²⁻), and ν(PO) modes of L-Ala-(3,4-dimethoxy)-L-Phe-PO₃H₂ suggested that these groups were mainly involved in the interaction with the silver colloid. Additionally, we proved that in the SERS spectrum of L-Ala-(3,4-dimethoxy)-(des-CH₂)-L-Phe-PO₃H₂, several vibrations of the CH₃ group were enhanced, indicating a flattened orientation of the peptide backbone on the silver surface.

https://doi.org/10.1002/jrs.1433

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