Orientation of a Key Glutamine Residue in the BLUF Domain from AppA Revealed by Mutagenesis, Spectroscopy, and Quantum Chemical Calculations
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- 作者：Masashi Unno ; Shinji Masuda ; Taka-aki Ono ; and Seigo Yamauchi
- 刊名：Journal of the American Chemical Society
- 出版年：2006
- 出版时间：May 3, 2006
- 年：2006
- 卷：128
- 期：17
- 页码：5638 - 5639
- 全文大小：105K
- 年卷期：v.128,no.17(May 3, 2006)
- ISSN：1520-5126
文摘
The flavin-adenine-dinucleotide-binding BLUF domain constitutes a new class of blue-light receptors, and the N-terminal domain of AppA is a representative of this family. A crystal structure of the BLUF domain from AppA suggested that a conserved Gln63 forms a hydrogen bond with the flavin N5 atom. Upon light excitation, this residue is proposed to undergo a ~180
rotation that leads to a rearrangement of a hydrogen bonding network. However, crystallographic studies on the other BLUF proteins claimed an opposite orientation for the glutamine residue. In this communication, we have revealed the presence of a Gln63-to-N5 hydrogen bond in the dark state of AppA by a combined approach of mutagenesis, spectroscopy, and quantum chemical calculations. The present finding supports the view that the reorientation of the Gln63 side chain is a key event in the signaling state formation of BLUF proteins.
rotation that leads to a rearrangement of a hydrogen bonding network. However, crystallographic studies on the other BLUF proteins claimed an opposite orientation for the glutamine residue. In this communication, we have revealed the presence of a Gln63-to-N5 hydrogen bond in the dark state of AppA by a combined approach of mutagenesis, spectroscopy, and quantum chemical calculations. The present finding supports the view that the reorientation of the Gln63 side chain is a key event in the signaling state formation of BLUF proteins.