In:
Angewandte Chemie International Edition, Wiley, Vol. 59, No. 18 ( 2020-04-27), p. 7089-7096
Abstract:
Here, we propose an experimental methodology based on femtosecond‐resolved fluorescence spectroscopy to measure the hydrogen (H)‐bond free energy of water at protein surfaces under isothermal conditions. A demonstration was conducted by installing a non‐canonical isostere of tryptophan (7‐azatryptophan) at the surface of a coiled‐coil protein to exploit the photoinduced proton transfer of its chromophoric moiety, 7‐azaindole. The H‐bond free energy of this biological water was evaluated by comparing the rates of proton transfer, sensitive to the hydration environment, at the protein surface and in bulk water, and it was found to be higher than that of bulk water by 0.4 kcal mol −1 . The free‐energy difference is dominated by the entropic cost in the H‐bond network among water molecules at the hydrophilic and charged protein surface. Our study opens a door to accessing the energetics and dynamics of local biological water to give insight into its roles in protein structure and function.
Type of Medium:
Online Resource
ISSN:
1433-7851
,
1521-3773
DOI:
10.1002/anie.202002025
Language:
English
Publisher:
Wiley
Publication Date:
2020
detail.hit.zdb_id:
2011836-3
detail.hit.zdb_id:
123227-7
