PMID- 17298090
OWN - NLM
STAT- MEDLINE
DCOM- 20070607
LR  - 20131121
IS  - 1520-6106 (Print)
IS  - 1520-5207 (Linking)
VI  - 111
IP  - 9
DP  - 2007 Mar 8
TI  - Photochemistry of a retinal protonated schiff-base analogue mimicking the opsin 
      shift of bacteriorhodopsin.
PG  - 2327-34
AB  - A retinal Schiff base analogue which artificially mimics the protein-induced red 
      shifting of absorption in bacteriorhodopsin (BR) has been investigated with 
      femtosecond multichannel pump probe spectroscopy. The objective is to determine 
      if the catalysis of retinal internal conversion in the native protein BR, which 
      absorbs at 570 nm, is directly correlated with the protein-induced Stokes 
      shifting of this absorption band otherwise known as the "opsin shift". Results 
      demonstrate that the red shift afforded in the model system does not hasten 
      internal conversion relative to that taking place in a free retinal-protonated 
      Schiff base (RPSB) in methanol solution, and stimulated emission takes place with 
      biexponential kinetics and characteristic timescales of approximately 2 and 10.5 
      ps. This shows that interactions between the prosthetic group and the protein 
      that lead to the opsin shift in BR are not directly involved in reducing the 
      excited-state lifetime by nearly an order of magnitude. A sub-picosecond phase of 
      spectral evolution, analogues of which are detected in photoexcited retinal 
      proteins and RPSBs in solution, is observed after excitation anywhere within the 
      intense visible absorption band. It consists of a large and discontinuous 
      spectral shift in excited-state absorption and is assigned to electronic 
      relaxation between excited states, a scenario which might also be relevant to 
      those systems as well. Finally, a transient excess bleach component that tunes 
      with the excitation wavelength is detected in the data and tentatively assigned 
      to inhomogeneous broadening in the ground state absorption band. Possible sources 
      of such inhomogeneity and its relevance to native RPSB photochemistry are 
      discussed.
FAU - Bismuth, Oshrat
AU  - Bismuth O
AD  - Department of Physical Chemistry, Hebrew University, Jerusalem 91904, Israel.
FAU - Friedman, Noga
AU  - Friedman N
FAU - Sheves, Mordechai
AU  - Sheves M
FAU - Ruhman, Sanford
AU  - Ruhman S
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20070214
PL  - United States
TA  - J Phys Chem B
JT  - The journal of physical chemistry. B
JID - 101157530
RN  - 0 (Aldehydes)
RN  - 0 (Protons)
RN  - 0 (Rod Opsins)
RN  - 0 (Schiff Bases)
RN  - 3K9958V90M (Ethanol)
RN  - 53026-44-1 (Bacteriorhodopsins)
SB  - IM
MH  - Aldehydes/chemistry
MH  - Bacteriorhodopsins/*chemistry
MH  - Biophysics/methods
MH  - Chemistry, Physical/methods
MH  - Ethanol/chemistry
MH  - Kinetics
MH  - Models, Chemical
MH  - Photochemistry/*methods
MH  - Photons
MH  - Protons
MH  - Rod Opsins/*chemistry
MH  - Schiff Bases/*chemistry
MH  - Static Electricity
MH  - Temperature
EDAT- 2007/02/15 09:00
MHDA- 2007/06/08 09:00
CRDT- 2007/02/15 09:00
PHST- 2007/02/15 09:00 [pubmed]
PHST- 2007/06/08 09:00 [medline]
PHST- 2007/02/15 09:00 [entrez]
AID - 10.1021/jp0669308 [doi]
PST - ppublish
SO  - J Phys Chem B. 2007 Mar 8;111(9):2327-34. doi: 10.1021/jp0669308. Epub 2007 Feb 
      14.