Coupled HOOP signature correlates with quantum yield of isorhodopsin and analog pigments

all-trans chromophore) is exceptionally high. This is currently explained by coherent coupling of the excited state electronic wavepacket with local vibrational nuclear modes, facilitating efficient cross-over at a conical intersection onto the photoproduct energy surface. The 9-cis counterpart of rhodopsin, dubbed isorhodopsin, has a much lower quantum yield (0.26+/-0.03), which, however, can be markedly enhanced by modification of the retinal chromophore (7,8-dihydro and 9-cyclopropyl derivatives). The coherent coupling in the excited state is promoted by torsional skeletal and coupled HOOP vibrational modes, in combination with a twisted conformation around the isomerization region. Since such torsion will strongly enhance the infrared intensity of coupled HOOP modes, we investigated FTIR difference spectra of rhodopsin, isorhodopsin and several analog pigments in the spectral range of isolated and coupled HCCH wags. As a result we propose that the coupled HOOP signature in these retinal pigments correlates with the distribution of torsion over counteracting segments in the retinylidene polyene chain. As such the HOOP signature can act as an indicator for the photoisomerization efficiency, and can explain the higher quantum yield of the 7,8-dihydro and 9-cyclopropyl-isorhodopsin analogs. -->
Popis souboru: application/pdf
Jazyk: English
ISSN: 0005-2728
Přístupová URL adresa: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6a174d92c23d8f93dabdb96760946023
https://hdl.handle.net/1887/45740
Rights: OPEN
Přírůstkové číslo: edsair.doi.dedup.....6a174d92c23d8f93dabdb96760946023
Autor: Johan Lugtenburg, Petra H. M. Bovee-Geurts, Willem J. DeGrip
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Biochimica et Biophysica Acta. Bioenergetics, 1858, 118-125
Biochimica et Biophysica Acta. Bioenergetics, 1858, 2, pp. 118-125
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS, 1858, 118-125
ISSN: 0005-2728
Popis: Contains fulltext : 169939.pdf (Publisher’s version ) (Closed access) With a quantum yield of 0.66+/-0.03 the photoisomerization efficiency of the visual pigment rhodopsin (11-cis-->all-trans chromophore) is exceptionally high. This is currently explained by coherent coupling of the excited state electronic wavepacket with local vibrational nuclear modes, facilitating efficient cross-over at a conical intersection onto the photoproduct energy surface. The 9-cis counterpart of rhodopsin, dubbed isorhodopsin, has a much lower quantum yield (0.26+/-0.03), which, however, can be markedly enhanced by modification of the retinal chromophore (7,8-dihydro and 9-cyclopropyl derivatives). The coherent coupling in the excited state is promoted by torsional skeletal and coupled HOOP vibrational modes, in combination with a twisted conformation around the isomerization region. Since such torsion will strongly enhance the infrared intensity of coupled HOOP modes, we investigated FTIR difference spectra of rhodopsin, isorhodopsin and several analog pigments in the spectral range of isolated and coupled HCCH wags. As a result we propose that the coupled HOOP signature in these retinal pigments correlates with the distribution of torsion over counteracting segments in the retinylidene polyene chain. As such the HOOP signature can act as an indicator for the photoisomerization efficiency, and can explain the higher quantum yield of the 7,8-dihydro and 9-cyclopropyl-isorhodopsin analogs.
Databáze: OpenAIRE
Externí odkaz: