TY - JOUR
T1 - Hydration properties of adenosine phosphate series as studied by microwave dielectric spectroscopy
AU - Mogami, George
AU - Wazawa, Tetsuichi
AU - Morimoto, Nobuyuki
AU - Kodama, Takao
AU - Suzuki, Makoto
N1 - Funding Information:
We thank T. Miyazaki (Tohoku Univ.) for the discussion and support and D. M. Standley (Osaka Univ.) for reading the manuscript. This study was supported in part by grants from the Scientific Research on Innovative Areas, Ministry of Education, Culture, Sports, Science and Technology, Japan ( 18031004 , 20118001 , 20118008 ), and Core Research of Evolutional Science and Technology of Japan Science and Technology Agency .
PY - 2011/2
Y1 - 2011/2
N2 - 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.
AB - 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.
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U2 - 10.1016/j.bpc.2010.11.006
DO - 10.1016/j.bpc.2010.11.006
M3 - Article
C2 - 21167630
AN - SCOPUS:79751533091
VL - 154
SP - 1
EP - 7
JO - Biophysical Chemistry
JF - Biophysical Chemistry
SN - 0301-4622
IS - 1
ER -