PMID- 20880715
OWN - NLM
STAT- MEDLINE
DCOM- 20110627
LR  - 20131121
IS  - 1873-2682 (Electronic)
IS  - 1011-1344 (Linking)
VI  - 102
IP  - 1
DP  - 2011 Jan 10
TI  - Photochemistry of a putative new class of sensory rhodopsin (SRIII) coded by xop2 
      of Haloarcular marismortui.
PG  - 45-54
LID - 10.1016/j.jphotobiol.2010.09.004 [doi]
AB  - Baliga et al. (2004) [1] reported the existence of a functionally unpredictable 
      opsin gene, named xop2, in Haloarcula marismortui, a holophilic archaeon. Ihara 
      et al. [38] performed molecular phylogenetic analysis and determined that the 
      product of xop2 belonged to a new class of opsins in the sensory rhodopsins. This 
      microbial rhodopsin was therefore named H. marismortui sensory rhodopsin III 
      (HmSRIII). Here, we functionally expressed HmSRIII in Escherichia coli cell 
      membranes to examine the photochemistry. The wavelength of maximum absorption 
      (lambda(max)) for HmSRIII was 506nm. We observed a very slow photocycle that completed 
      in  approximately 50s. Intermediates were defined as M (lambda(max) approximately 380nm), N (lambda(max) approximately 460nm) and O 
      (lambda(max) approximately 530nm) 0.01s after the flash excitation. The nomenclature for these 
      intermediates was based on their locations along the absorption maxima of 
      bacteriorhodopsin. Analysis of laser-flash-photolysis data in the presence and 
      absence of azide gave the following results: (1) an equilibrium between N and O 
      was attained, (2) the direct product of the M-decay was O but not N, and (3) the 
      last photo-intermediate (HmSRIII') had a lambda(max) similar to that of the original, 
      and its decay rate was very slow. Resonance Raman spectroscopy revealed that this 
      N-intermediate had 13-cis retinal conformation. Proton uptake occurred during the 
      course of M-decay, whereas proton release occurred during the course of O-decay 
      (or exactly N-O equilibrium). Very weak proton-pumping activity was observed 
      whose direction is the same as that of bacteriorhodopsin, a typical light-driven 
      proton pump.
CI  - Copyright A(c) 2010 Elsevier B.V. All rights reserved.
FAU - Nakao, Yutaka
AU  - Nakao Y
AD  - Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan.
FAU - Kikukawa, Takashi
AU  - Kikukawa T
FAU - Shimono, Kazumi
AU  - Shimono K
FAU - Tamogami, Jun
AU  - Tamogami J
FAU - Kimitsuki, Noriko
AU  - Kimitsuki N
FAU - Nara, Toshifumi
AU  - Nara T
FAU - Unno, Masashi
AU  - Unno M
FAU - Ihara, Kunio
AU  - Ihara K
FAU - Kamo, Naoki
AU  - Kamo N
LA  - eng
PT  - Journal Article
DEP - 20100921
PL  - Switzerland
TA  - J Photochem Photobiol B
JT  - Journal of photochemistry and photobiology. B, Biology
JID - 8804966
RN  - 0 (Proton Pumps)
RN  - 0 (Protons)
RN  - 0 (Schiff Bases)
RN  - 0 (Sensory Rhodopsins)
RN  - 4QD397987E (Histidine)
RN  - RR725D715M (Retinaldehyde)
SB  - IM
MH  - Absorption
MH  - Cell Membrane/genetics
MH  - Darkness
MH  - Escherichia coli/cytology/genetics
MH  - Halobacillus/*genetics
MH  - Histidine/metabolism
MH  - Hydrogen-Ion Concentration
MH  - Isomerism
MH  - Kinetics
MH  - *Photochemical Processes
MH  - Photolysis
MH  - Protein Stability
MH  - Proton Pumps/metabolism
MH  - Protons
MH  - Retinaldehyde/chemistry
MH  - Schiff Bases/chemistry
MH  - Sensory Rhodopsins/*chemistry/*genetics/isolation & purification/metabolism
MH  - Spectrum Analysis, Raman
EDAT- 2010/10/01 06:00
MHDA- 2011/06/28 06:00
CRDT- 2010/10/01 06:00
PHST- 2010/07/20 00:00 [received]
PHST- 2010/08/31 00:00 [revised]
PHST- 2010/09/03 00:00 [accepted]
PHST- 2010/10/01 06:00 [entrez]
PHST- 2010/10/01 06:00 [pubmed]
PHST- 2011/06/28 06:00 [medline]
AID - S1011-1344(10)00217-4 [pii]
AID - 10.1016/j.jphotobiol.2010.09.004 [doi]
PST - ppublish
SO  - J Photochem Photobiol B. 2011 Jan 10;102(1):45-54. doi: 
      10.1016/j.jphotobiol.2010.09.004. Epub 2010 Sep 21.