「BIOPHYSICS」にTetsuya Fukuda et al. “Detection of a protein-bound water vibration of halorhodopsin in aqueous solution”を掲載

2013 December 24 BPPB


Tetsuya Fukuda, Kosuke Muroda, Hideki Kandori
“Detection of a protein-bound water vibration of halorhodopsin in aqueous solution”

【Editor's Summary】

タンパク質の内部結合水は構造や機能に重要な役割を果たすと考えられているが、それを実験的に示すのは容易なことではない。水溶液中の水の濃度は55 Mであり55 μMのタンパク質に結合した1分子の水を観測するためには100万個の中から1個の水の信号を抽出する必要がある。今回、福田らは全反射赤外分光をハロロドプシンに適用し、Cl-とBr-の差を室温、水中で測定することにより、この膜タンパク質の活性中心に結合した水分子の振動状態を捉えることに成功した。

Detection of a protein-bound water vibration of a light-driven chloride-ion pump halorhodopsin in aqueous solution

Protein-bound water molecules play crucial roles in their structure and function, but their detection is an experimental challenge, particularly in aqueous solution at room temperature. By applying attenuated total reflection (ATR) Fourier-transform infrared (FTIR) spectroscopy to a membrane protein halorhodopsin in NaCl and NaBr, Fukuda et al. successfully detected an O-H stretching vibration of protein-bound water molecules. The water O-H stretching vibrations of pHR(Cl-) and pHR (Br-) are located at 3617 and 3630 cm-1, respectively, and the water molecule presumably resides near the transported chloride ion in the light-driven pump.

BIOPHYSICS, Vol.9, pp.167-172


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