Hydration properties of adenosine phosphate series as studied by microwave dielectric spectroscopy

George Mogami, Tetsuichi Wazawa, Nobuyuki Morimoto, Takao Kodama, Makoto Suzuki

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

Hydration properties of adenine nucleotides and orthophosphate (Pi) in aqueous solutions adjusted to pH = 8 with NaOH were studied by high-resolution microwave dielectric relaxation (DR) spectroscopy at 20 °C. The dielectric spectra were analyzed using a mixture theory combined with a least-squares Debye decomposition method. Solutions of Pi and adenine nucleotides showed qualitatively similar dielectric properties described by two Debye components. One component was characterized by a relaxation frequency (fc = 18.8-19.7 GHz) significantly higher than that of bulk water (17 GHz) and the other by a much lower fc (6.4-7.6 GHz), which are referred to here as hyper-mobile water and constrained water, respectively. By contrast, a hydration shell of only the latter type was found for adenosine (fc ∼ 6.7 GHz). The present results indicate that phosphoryl groups are mostly responsible for affecting the structure of the water surrounding the adenine nucleotides by forming one constrained water layer and an additional three or four layers of hyper-mobile water.

Original languageEnglish
Pages (from-to)1-7
Number of pages7
JournalBiophysical Chemistry
Volume154
Issue number1
DOIs
Publication statusPublished - 2011 Feb

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Organic Chemistry

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