Abstract
Phoborhodopsin (pR; also sensory rhodopsin II, sRII) is a retinoid protein in Halobacterium salinarum and works as a receptor of negative phototaxis. Pharaonis phoborhodopsin (ppR; also pharaonis sensory rhodopsin II, psRII) is a corresponding protein of Natronobacterium pharaonis. In bacterial membrane, ppR forms a complex with its transducer pHtrII, and this complex transmits the light signal to the sensory system in the cytoplasm. We expressed pHtrII-free ppR or ppR-pHtrII complex in H. salinarum Pho81/wr- cells. Flash-photolysis experiments showed no essential changes between pHtrII-free ppR and the complex. Using SnO2 electrode, which works as a sensitive pH electrode, and envelope membrane vesicles, we showed the photo-induced outward proton transport. This membranous proton transport was also shown using membrane vesicles from Escherichia coli in which ppR was functionally expressed. On the other hand, the proton transport was ceased when ppR formed a complex with pHtrII. Using membrane sheet, it was shown that the complex undergoes first proton uptake and then release during the photocycle, the same as pHtrII-free ppR, although the net proton transport ceases. Taking into consideration that the complex of sRII (pR) and its transducer undergoes extracellular proton circulation (J. Sasaki and J. L. Spudich, 1999, Biophys. J. 77:2145-2152), we inferred that association with pHtrII closes a cytoplasmic channel of ppR, which lead to the extracellular proton circulation.
| Original language | English |
|---|---|
| Pages (from-to) | 916-922 |
| Number of pages | 7 |
| Journal | Biophysical Journal |
| Volume | 80 |
| Issue number | 2 |
| Publication status | Published - 2001 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biophysics
Cite this
Photo-induced proton transport of pharaonis phoborhodopsin (sensory rhodopsin II) is ceased by association with the transducer. / Sudo, Yuki; Iwamoto, Masayuki; Shimono, Kazumi; Sumi, Masato; Kamo, Naoki.
In: Biophysical Journal, Vol. 80, No. 2, 2001, p. 916-922.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Photo-induced proton transport of pharaonis phoborhodopsin (sensory rhodopsin II) is ceased by association with the transducer
AU - Sudo, Yuki
AU - Iwamoto, Masayuki
AU - Shimono, Kazumi
AU - Sumi, Masato
AU - Kamo, Naoki
PY - 2001
Y1 - 2001
N2 - Phoborhodopsin (pR; also sensory rhodopsin II, sRII) is a retinoid protein in Halobacterium salinarum and works as a receptor of negative phototaxis. Pharaonis phoborhodopsin (ppR; also pharaonis sensory rhodopsin II, psRII) is a corresponding protein of Natronobacterium pharaonis. In bacterial membrane, ppR forms a complex with its transducer pHtrII, and this complex transmits the light signal to the sensory system in the cytoplasm. We expressed pHtrII-free ppR or ppR-pHtrII complex in H. salinarum Pho81/wr- cells. Flash-photolysis experiments showed no essential changes between pHtrII-free ppR and the complex. Using SnO2 electrode, which works as a sensitive pH electrode, and envelope membrane vesicles, we showed the photo-induced outward proton transport. This membranous proton transport was also shown using membrane vesicles from Escherichia coli in which ppR was functionally expressed. On the other hand, the proton transport was ceased when ppR formed a complex with pHtrII. Using membrane sheet, it was shown that the complex undergoes first proton uptake and then release during the photocycle, the same as pHtrII-free ppR, although the net proton transport ceases. Taking into consideration that the complex of sRII (pR) and its transducer undergoes extracellular proton circulation (J. Sasaki and J. L. Spudich, 1999, Biophys. J. 77:2145-2152), we inferred that association with pHtrII closes a cytoplasmic channel of ppR, which lead to the extracellular proton circulation.
AB - Phoborhodopsin (pR; also sensory rhodopsin II, sRII) is a retinoid protein in Halobacterium salinarum and works as a receptor of negative phototaxis. Pharaonis phoborhodopsin (ppR; also pharaonis sensory rhodopsin II, psRII) is a corresponding protein of Natronobacterium pharaonis. In bacterial membrane, ppR forms a complex with its transducer pHtrII, and this complex transmits the light signal to the sensory system in the cytoplasm. We expressed pHtrII-free ppR or ppR-pHtrII complex in H. salinarum Pho81/wr- cells. Flash-photolysis experiments showed no essential changes between pHtrII-free ppR and the complex. Using SnO2 electrode, which works as a sensitive pH electrode, and envelope membrane vesicles, we showed the photo-induced outward proton transport. This membranous proton transport was also shown using membrane vesicles from Escherichia coli in which ppR was functionally expressed. On the other hand, the proton transport was ceased when ppR formed a complex with pHtrII. Using membrane sheet, it was shown that the complex undergoes first proton uptake and then release during the photocycle, the same as pHtrII-free ppR, although the net proton transport ceases. Taking into consideration that the complex of sRII (pR) and its transducer undergoes extracellular proton circulation (J. Sasaki and J. L. Spudich, 1999, Biophys. J. 77:2145-2152), we inferred that association with pHtrII closes a cytoplasmic channel of ppR, which lead to the extracellular proton circulation.
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M3 - Article
C2 - 11159458
AN - SCOPUS:0035142193
VL - 80
SP - 916
EP - 922
JO - Biophysical Journal
JF - Biophysical Journal
SN - 0006-3495
IS - 2
ER -