論文

査読有り 招待有り
2019年8月1日

Dipole–dipole interactions between tryptophan side chains and hydration water molecules dominate the observed dynamic stokes shift of lysozyme

Biochimica et Biophysica Acta - General Subjects
  • Fukuda A
  • ,
  • Oroguchi T
  • ,
  • Nakasako M

1864
2
開始ページ
129406(1)
終了ページ
129406(11)
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1016/j.bbagen.2019.07.015
出版者・発行元
Biochimica et Biophysica Acta - General Subjects

© 2019 Elsevier B.V. The fluorescence intensity of tryptophan residues in hen egg-white lysozyme was measured up to 500 ps after the excitation by irradiation pulses at 290 nm. From the time-dependent variation of fluorescence intensity in a wavelength range of 320–370 nm, the energy relaxation in the dynamic Stokes shift was reconstructed as the temporal variation in wavenumber of the estimated fluorescence maximum. The relaxation was approximated by two exponential curves with decay constants of 1.2 and 26.7 ps. To interpret the relaxation, a molecular dynamics simulation of 75 ns was conducted for lysozyme immersed in a water box. From the simulation, the energy relaxation in the electrostatic interactions of each tryptophan residue was evaluated by using a scheme derived from the linear response theory. Dipole–dipole interactions between each of the Trp62 and Trp123 residues and hydration water molecules displayed an energy relaxation similar to that experimentally observed regarding time constants and magnitudes. The side chains of these residues were partly or fully exposed to the solvent. In addition, by inspecting the variation in dipole moments of the hydration water molecules around lysozyme, it was suggested that the observed relaxation could be attributed to the orientational relaxation of hydration water molecules participating in the hydrogen-bond network formed around each of the two tryptophan residues.

リンク情報
DOI
https://doi.org/10.1016/j.bbagen.2019.07.015
URL
https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85070216761&origin=inward
ID情報
  • DOI : 10.1016/j.bbagen.2019.07.015
  • ISSN : 0304-4165

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