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Tuning the Protein‐Induced Absorption Shifts of Retinal in Engineered Rhodopsin Mimics
Author(s) -
Suomivuori CarlMikael,
Lang Lucas,
Sundholm Dage,
GamizHernandez Ana P.,
Kaila Ville R. I.
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201505126
Subject(s) - chromophore , rhodopsin , retinal , chemistry , bacteriorhodopsin , excited state , ground state , density functional theory , absorption (acoustics) , photochemistry , chemical physics , materials science , computational chemistry , physics , atomic physics , biochemistry , membrane , composite material
Rational design of light‐capturing properties requires understanding the molecular and electronic structure of chromophores in their native chemical or biological environment. We employ here large‐scale quantum chemical calculations to study the light‐capturing properties of retinal in recently designed human cellular retinol binding protein II (hCRBPII) variants (Wang et al. Science , 2012 , 338 , 1340–1343). Our calculations show that these proteins absorb across a large part of the visible spectrum by combined polarization and electrostatic effects. These effects stabilize the ground or excited state energy levels of the retinal by perturbing the Schiff‐base or β‐ionone moieties of the chromophore, which in turn modulates the amount of charge transfer within the molecule. Based on the predicted tuning principles, we design putative in silico mutations that further shift the absorption properties of retinal in hCRBPII towards the ultraviolet and infrared regions of the spectrum.