Abstract
Sensory rhodopsin II (SRII, also called pharaonis phoborhodopsin, ppR) is responsible for negative phototaxis in Natronomonas pharaonis. Photoisomerization of the retinal chromophore from all-trans to 13-cis initiates conformational changes in the protein, leading to activation of the cognate transducer protein (HtrII). We previously observed enhancement of the C 14-D stretching vibration of the retinal chromophore at 2244 cm -1 upon formation of the K state and interpreted that a steric constraint occurs at the C14D group in SRIIK. Here, we identify the counterpart of the C14D group as Thr204, because the C14-D stretching signal disappeared in T204A, T204S, and T204C mutants as well as a C14-HOOP (hydrogen out-of-plane) vibration at 864 cm-1. Although the K state of the wild-type bacteriorhodopsin (BR), a light-driven proton pump, possesses neither 2244 nor 864 cm-1 bands, both signals appeared for the K state of a triple mutant of BR that functions as a light sensor (P200T/V210Y/A215T). We found a positive correlation between these vibrational amplitudes of the C14 atom at 77 K and the physiological phototaxis response. These observations strongly suggest that the steric constraint between the C14 group of retinal and Thr204 of the protein is a prerequisite for light-signal transduction by SRII.
| Original language | English |
|---|---|
| Pages (from-to) | 6208-6215 |
| Number of pages | 8 |
| Journal | Biochemistry |
| Volume | 47 |
| Issue number | 23 |
| DOIs | |
| Publication status | Published - Jun 10 2008 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Steric constraint in the primary photoproduct of sensory rhodopsin II is a prerequisite for light-signal transfer to HtrII. / Ito, Motohiro; Sudo, Yuki; Furutani, Yuji; Okitsu, Takashi; Wada, Akimori; Homma, Michio; Spudich, John L.; Kandori, Hideki.
In: Biochemistry, Vol. 47, No. 23, 10.06.2008, p. 6208-6215.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Steric constraint in the primary photoproduct of sensory rhodopsin II is a prerequisite for light-signal transfer to HtrII
AU - Ito, Motohiro
AU - Sudo, Yuki
AU - Furutani, Yuji
AU - Okitsu, Takashi
AU - Wada, Akimori
AU - Homma, Michio
AU - Spudich, John L.
AU - Kandori, Hideki
PY - 2008/6/10
Y1 - 2008/6/10
N2 - Sensory rhodopsin II (SRII, also called pharaonis phoborhodopsin, ppR) is responsible for negative phototaxis in Natronomonas pharaonis. Photoisomerization of the retinal chromophore from all-trans to 13-cis initiates conformational changes in the protein, leading to activation of the cognate transducer protein (HtrII). We previously observed enhancement of the C 14-D stretching vibration of the retinal chromophore at 2244 cm -1 upon formation of the K state and interpreted that a steric constraint occurs at the C14D group in SRIIK. Here, we identify the counterpart of the C14D group as Thr204, because the C14-D stretching signal disappeared in T204A, T204S, and T204C mutants as well as a C14-HOOP (hydrogen out-of-plane) vibration at 864 cm-1. Although the K state of the wild-type bacteriorhodopsin (BR), a light-driven proton pump, possesses neither 2244 nor 864 cm-1 bands, both signals appeared for the K state of a triple mutant of BR that functions as a light sensor (P200T/V210Y/A215T). We found a positive correlation between these vibrational amplitudes of the C14 atom at 77 K and the physiological phototaxis response. These observations strongly suggest that the steric constraint between the C14 group of retinal and Thr204 of the protein is a prerequisite for light-signal transduction by SRII.
AB - Sensory rhodopsin II (SRII, also called pharaonis phoborhodopsin, ppR) is responsible for negative phototaxis in Natronomonas pharaonis. Photoisomerization of the retinal chromophore from all-trans to 13-cis initiates conformational changes in the protein, leading to activation of the cognate transducer protein (HtrII). We previously observed enhancement of the C 14-D stretching vibration of the retinal chromophore at 2244 cm -1 upon formation of the K state and interpreted that a steric constraint occurs at the C14D group in SRIIK. Here, we identify the counterpart of the C14D group as Thr204, because the C14-D stretching signal disappeared in T204A, T204S, and T204C mutants as well as a C14-HOOP (hydrogen out-of-plane) vibration at 864 cm-1. Although the K state of the wild-type bacteriorhodopsin (BR), a light-driven proton pump, possesses neither 2244 nor 864 cm-1 bands, both signals appeared for the K state of a triple mutant of BR that functions as a light sensor (P200T/V210Y/A215T). We found a positive correlation between these vibrational amplitudes of the C14 atom at 77 K and the physiological phototaxis response. These observations strongly suggest that the steric constraint between the C14 group of retinal and Thr204 of the protein is a prerequisite for light-signal transduction by SRII.
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U2 - 10.1021/bi8003507
DO - 10.1021/bi8003507
M3 - Article
C2 - 18479149
AN - SCOPUS:44949169843
VL - 47
SP - 6208
EP - 6215
JO - Biochemistry
JF - Biochemistry
SN - 0006-2960
IS - 23
ER -