Abstract
Sensory rhodopsin II (SRII) is a negative phototaxis receptor containing retinal as its chromophore, which mediates the avoidance of blue light. The signal transduction is initiated by the photoisomerization of the retinal chromophore, resulting in conformational changes of the protein which are transmitted to a transducer protein. To gain insight into the SRII sensing mechanism, we employed time-resolved ultraviolet resonance Raman spectroscopy monitoring changes in the protein structure in the picosecond time range following photoisomerization. We used a 450 nm pump pulse to initiate the SRII photocycle and two kinds of probe pulses with wavelengths of 225 and 238 nm to detect spectral changes in the tryptophan and tyrosine bands, respectively. The observed spectral changes of the Raman bands are most likely due to tryptophan and tyrosine residues located in the vicinity of the retinal chromophore, i.e., Trp76, Trp171, Tyr51, or Tyr174. The 225 nm UVRR spectra exhibited bleaching of the intensity for all the tryptophan bands within the instrumental response time, followed by a partial recovery with a time constant of 30 ps and no further changes up to 1 ns. In the 238 nm UVRR spectra, a fast recovering component was observed in addition to the 30 ps time constant component. A comparison between the spectra of the WT and Y174F mutant of SRII indicates that Tyr174 changes its structure and/or environment upon chromophore photoisomerization. These data represent the first real-time observation of the structural change of Tyr174, of which functional importance was pointed out previously.
| Original language | English |
|---|---|
| Pages (from-to) | 3170-3180 |
| Number of pages | 11 |
| Journal | Biochemistry |
| Volume | 50 |
| Issue number | 15 |
| DOIs | |
| Publication status | Published - Apr 19 2011 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Direct observation of the structural change of Tyr174 in the primary reaction of sensory Rhodopsin II. / Mizuno, Misao; Sudo, Yuki; Homma, Michio; Mizutani, Yasuhisa.
In: Biochemistry, Vol. 50, No. 15, 19.04.2011, p. 3170-3180.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Direct observation of the structural change of Tyr174 in the primary reaction of sensory Rhodopsin II
AU - Mizuno, Misao
AU - Sudo, Yuki
AU - Homma, Michio
AU - Mizutani, Yasuhisa
PY - 2011/4/19
Y1 - 2011/4/19
N2 - Sensory rhodopsin II (SRII) is a negative phototaxis receptor containing retinal as its chromophore, which mediates the avoidance of blue light. The signal transduction is initiated by the photoisomerization of the retinal chromophore, resulting in conformational changes of the protein which are transmitted to a transducer protein. To gain insight into the SRII sensing mechanism, we employed time-resolved ultraviolet resonance Raman spectroscopy monitoring changes in the protein structure in the picosecond time range following photoisomerization. We used a 450 nm pump pulse to initiate the SRII photocycle and two kinds of probe pulses with wavelengths of 225 and 238 nm to detect spectral changes in the tryptophan and tyrosine bands, respectively. The observed spectral changes of the Raman bands are most likely due to tryptophan and tyrosine residues located in the vicinity of the retinal chromophore, i.e., Trp76, Trp171, Tyr51, or Tyr174. The 225 nm UVRR spectra exhibited bleaching of the intensity for all the tryptophan bands within the instrumental response time, followed by a partial recovery with a time constant of 30 ps and no further changes up to 1 ns. In the 238 nm UVRR spectra, a fast recovering component was observed in addition to the 30 ps time constant component. A comparison between the spectra of the WT and Y174F mutant of SRII indicates that Tyr174 changes its structure and/or environment upon chromophore photoisomerization. These data represent the first real-time observation of the structural change of Tyr174, of which functional importance was pointed out previously.
AB - Sensory rhodopsin II (SRII) is a negative phototaxis receptor containing retinal as its chromophore, which mediates the avoidance of blue light. The signal transduction is initiated by the photoisomerization of the retinal chromophore, resulting in conformational changes of the protein which are transmitted to a transducer protein. To gain insight into the SRII sensing mechanism, we employed time-resolved ultraviolet resonance Raman spectroscopy monitoring changes in the protein structure in the picosecond time range following photoisomerization. We used a 450 nm pump pulse to initiate the SRII photocycle and two kinds of probe pulses with wavelengths of 225 and 238 nm to detect spectral changes in the tryptophan and tyrosine bands, respectively. The observed spectral changes of the Raman bands are most likely due to tryptophan and tyrosine residues located in the vicinity of the retinal chromophore, i.e., Trp76, Trp171, Tyr51, or Tyr174. The 225 nm UVRR spectra exhibited bleaching of the intensity for all the tryptophan bands within the instrumental response time, followed by a partial recovery with a time constant of 30 ps and no further changes up to 1 ns. In the 238 nm UVRR spectra, a fast recovering component was observed in addition to the 30 ps time constant component. A comparison between the spectra of the WT and Y174F mutant of SRII indicates that Tyr174 changes its structure and/or environment upon chromophore photoisomerization. These data represent the first real-time observation of the structural change of Tyr174, of which functional importance was pointed out previously.
UR - http://www.scopus.com/inward/record.url?scp=79953847127&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79953847127&partnerID=8YFLogxK
U2 - 10.1021/bi101817y
DO - 10.1021/bi101817y
M3 - Article
C2 - 21401124
AN - SCOPUS:79953847127
VL - 50
SP - 3170
EP - 3180
JO - Biochemistry
JF - Biochemistry
SN - 0006-2960
IS - 15
ER -