PMID- 26074351
OWN - NLM
STAT- MEDLINE
DCOM- 20160325
LR  - 20150625
IS  - 1463-9084 (Electronic)
IS  - 1463-9076 (Linking)
VI  - 17
IP  - 26
DP  - 2015 Jul 14
TI  - Impacts of retinal polyene (de)methylation on the photoisomerization mechanism 
      and photon energy storage of rhodopsin.
PG  - 17169-81
LID - 10.1039/c5cp01939g [doi]
AB  - Ab initio multiconfigurational quantum chemical methodology combined with 
      molecular mechanics (CASPT2//CASSCF/AMBER) was applied to probe impacts of 
      retinal protonated Schiff base (RPSB) polyene methylation and/or demethylation on 
      the mechanism of photochemical isomerization in bovine rhodopsin. We have 
      examined structural and spectroscopic properties of wild-type rhodopsin (with 
      11-cis-9,13-dimethyl-RPSB) and artificial rhodopsins, hosting four 11-cis-RPSB 
      derivatives, 13-demethyl-, 9-demethyl-, 10-methyl-13-demethyl-, and 
      10-methyl-RPSB, evolving along the photoisomerization coordinate. It is found 
      that the addition of 10-methyl or/and deletion of 9-/13-methyl groups do not 
      appear to interfere structurally with the photoisomerization pathway in the S1 
      excited state. Remarkably, the two-mode space-saving mechanism initiated by bond 
      order inversion and followed by asynchronous bicycle-pedal distortion in the RPSB 
      backbone drives the photoreaction in all rhodopsin analogues studied here. 
      However, methylation and/or demethylation is responsible for perturbation of 
      excess energy deposited in the conical intersection structures. The analysis of 
      photon energy stored by bathorhodopsin in synthetic pigments reveals that it is 
      affected by steric crowding of methyl substituents in the RPSB backbone.
FAU - Walczak, Elzbieta
AU  - Walczak E
AD  - Department of Chemistry, Wroclaw University of Technology, Wyb. Wyspianskiego 27, 
      50-370 Wroclaw, Poland. tadeusz.andruniow@pwr.wroc.pl.
FAU - Andruniow, Tadeusz
AU  - Andruniow T
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Phys Chem Chem Phys
JT  - Physical chemistry chemical physics : PCCP
JID - 100888160
RN  - 0 (Polyenes)
RN  - 9009-81-8 (Rhodopsin)
SB  - IM
MH  - Animals
MH  - Cattle
MH  - Methylation
MH  - Molecular Structure
MH  - *Photochemical Processes
MH  - *Photons
MH  - Polyenes/*chemistry
MH  - Quantum Theory
MH  - Rhodopsin/*chemistry
MH  - Stereoisomerism
EDAT- 2015/06/16 06:00
MHDA- 2016/03/26 06:00
CRDT- 2015/06/16 06:00
PHST- 2015/06/16 06:00 [entrez]
PHST- 2015/06/16 06:00 [pubmed]
PHST- 2016/03/26 06:00 [medline]
AID - 10.1039/c5cp01939g [doi]
PST - ppublish
SO  - Phys Chem Chem Phys. 2015 Jul 14;17(26):17169-81. doi: 10.1039/c5cp01939g.