2018年11月15日
Resonance Raman Investigation of the Chromophore Structure of Heliorhodopsins.
The journal of physical chemistry letters
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- 巻
- 9
- 号
- 22
- 開始ページ
- 6431
- 終了ページ
- 6436
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1021/acs.jpclett.8b02741
Heliorhodopsins (HeRs) are a new category of retinal-bound proteins recently discovered through functional metagenomics analysis that exhibit obvious differences from type-1 microbial rhodopsins. We conducted the first detailed structural characterization of the retinal chromophore in HeRs using resonance Raman spectroscopy. The observed spectra clearly show that the Schiff base of the chromophore is protonated and forms a strong hydrogen bond to a species other than a water molecule, highly likely a counterion residue. The vibrational mode of the Schiff base of HeRs exhibits similarities with that of photosensory microbial rhodopsins, that is consistent with the previous proposal that HeRs function as photosensors. We also revealed unusual spectral features of the in-plane chain vibrations of the chromophore, suggesting an unprecedented geometry of the Schiff base caused by a difference in the retinal pocket structure of HeRs. These data demonstrate structural characteristics of the photoreceptive site in this novel type of rhodopsin family.
- リンク情報
- ID情報
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- DOI : 10.1021/acs.jpclett.8b02741
- PubMed ID : 30351947