Effects of conformation and hydrogen bonding on the C=C and NCN stretchingRaman bands of N-deuterated histidinium

Hirotsugu Hiramatsu, Noriko Miki, Hideo Takeuchi

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Histidine is an important and versatile amino acid residue that plays avariety of structural and functional roles in proteins. Although the Raman bandsof histidine are generally weak, histidine in the N-deuterated cationic formwith imidazole Nπ - D and Nτ - D bonds (N-deuteratedhistidinium) gives two strong Raman bands assignable to the C 4=C5 stretch (νC=C) and the Nπ - C2 - Nτ symmetric stretch (νNCN) of the imidazolering. We examined the Raman spectra of N-deuterated histidinium in 12 crystalswith known structures. The observed νC=C and νNCNwavenumbers were analyzed to find empirical correlations with the conformationand hydrogen bonding. The effect of conformation on the vibrational wavenumberwas expressed as a threefold cosine function of the C α - Cβ - C4=C5 torsional angle. The effect ofhydrogen bonding at Nπ or Nτ was assumed to be proportional tothe inverse sixth power of the distance between the hydrogen and acceptoratoms. Multiple linear regression analysis clearly shows that the conformationaleffect on the vibrational wavenumber is comparable for νC=C andνNCN. The hydrogen bond at Nπ weakly lowers theνC=C wavenumber and substantially raises the νNCNwavenumber. On the other hand, the hydrogen bond at Nτ strongly raises theνC=C wavenumber but does not affect the νNCNwavenumber. These empirical correlations may be useful in Raman spectralanalysis of the conformation and hydrogen bonding states of histidine residuesin proteins.

Original languageEnglish
Pages (from-to)1708-1713
Number of pages6
JournalJournal of Raman Spectroscopy
Volume41
Issue number12
DOIs
Publication statusPublished - 2010 Dec 1

Keywords

  • Raman marker
  • conformation
  • histidine
  • hydrogen bond

ASJC Scopus subject areas

  • Materials Science(all)
  • Spectroscopy

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