Backbone Modification of Retinal Induces Protein-like Excited State Dynamics in Solution

Sovdat, Tina; Bassolino, Giovanni; Liebel, Matz; Schnedermann, Christoph; Fletcher, Stephen P.; Kukura, Philipp

doi:10.1021/ja3007929

Cited by 44 publications

(83 citation statements)

References 37 publications

(47 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If this is the case, the larger the velocity of the S 1 reactant moving toward the CI, the higher is the reaction quantum yield consistently with a Landau-Zener model (52). Although recent studies have denied the existence of such a correlation for the retinal chromophore in solution (53,54), this does not exclude that such correlation holds in the protein environment and when the S 1 lifetime is below a 100 fs threshold. In fact, this is in line with the more complete semiclassical treatment introduced by Weiss and Warshel (50) whose validity is also supported by the sudden change in charge distribution seen at decay in our models (SI Appendix, Fig.…”

Section: Significancementioning

confidence: 99%

Comparison of the isomerization mechanisms of human melanopsin and invertebrate and vertebrate rhodopsins

Rinaldi

Melaccio

Gozem

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Comparative modeling and ab initio multiconfigurational quantum chemistry are combined to investigate the reactivity of the human nonvisual photoreceptor melanopsin. It is found that both the thermal and photochemical isomerization of the melanopsin 11-cis retinal chromophore occur via a space-saving mechanism involving the unidirectional, counterclockwise twisting of the =C11H-C12H= moiety with respect to its Lys340-linked frame as proposed by Warshel for visual pigments [Warshel A (1976) Nature 260 (5553):679-683]. A comparison with the mechanisms documented for vertebrate (bovine) and invertebrate (squid) visual photoreceptors shows that such a mechanism is not affected by the diversity of the three chromophore cavities. Despite such invariance, trajectory computations indicate that although all receptors display less than 100 fs excited state dynamics, human melanopsin decays from the excited state ∼40 fs earlier than bovine rhodopsin. Some diversity is also found in the energy barriers controlling thermal isomerization. Human melanopsin features the highest computed barrier which appears to be ∼2.5 kcal mol −1 higher than that of bovine rhodopsin. When assuming the validity of both the reaction speed/quantum yield correlation discussed by Warshel, Mathies and coworkers [Weiss RM, Warshel A (1979) J Am Chem Soc 101:6131-6133; Schoenlein RW, Peteanu LA, Mathies RA, Shank CV (1991) Science 254(5030):412-415] and of a relationship between thermal isomerization rate and thermal activation of the photocycle, melanopsin turns out to be a highly sensitive pigment consistent with the low number of melanopsincontaining cells found in the retina and with the extraretina location of melanopsin in nonmammalian vertebrates.F or a long time it was assumed that the human retina contains only two types of photoreceptor cells: the rods and cones responsible for dim-light and daylight vision, respectively. However, recent studies have revealed the existence of a small number of intrinsically photosensitive retinal ganglion cells (ipRGCs) that regulate nonvisual photoresponses (1). ipRGCs express an atypical opsin-like protein named melanopsin (2, 3) which plays a role in the regulation of unconscious visual reflexes and in the synchronization of endogenous physiological responses to the dawn/dusk cycle (circadian rhythms) (4, 5).Melanopsins are unique among vertebrate photoreceptors because their amino acid sequence shares greater similarity to invertebrate than vertebrate rhodopsin (i.e., the photoreceptor of rods) (6, 7). Like rhodopsins, melanopsins feature an up-down bundle architecture of seven transmembrane α-helices incorporating the 11-cis isomer of retinal as a covalently bound protonated Schiff base (PSB11 in Fig. 1A). Light-induced (i.e., photochemical) isomerization of PSB11 to its all-trans isomer (PSBAT) triggers an opsin conformational change that, ultimately, activates the receptor and signaling cascade (8, 9). However, similar to invertebrate and in contrast to vertebrate rhodopsins, melanopsins are bistable ...

show abstract

Section: Significancementioning

confidence: 99%

Comparison of the isomerization mechanisms of human melanopsin and invertebrate and vertebrate rhodopsins

Rinaldi

Melaccio

Gozem

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…Among the recent studies aiming to achieve such knowledge, the works by Kukura et.al and Garavelli et.al are significant. 6–8 Kukura et.al investigated the photoisomerization of several artificial rPSB pigments in methanol solution using time-resolved spectroscopy. 6,7 An interesting result from their experiments is that the introduction of a Me group at the C10 position (10MerPSB) of the native rPSB backbone (see Scheme 1A) redshifted the absorption wavelength by only few nm but decreases the original excited state lifetime from 4 to 0.7 ps.…”

mentioning

confidence: 99%

Electronic State Mixing Controls the Photoreactivity of a Rhodopsin with all-trans Chromophore Analogues

Manathunga

Yang

Olivucci

2018

J. Phys. Chem. Lett.

View full text Add to dashboard Cite

Rhodopsins hosting synthetic retinal protonated Schiff base analogues are important for developing tools for optogenetics and high-resolution imaging. The ideal spectroscopic properties of such analogues include long-wavelength absorption/emission and fast/hindered photoisomerization. While the former may be achieved, for instance, by elongating the chromophore π-system, the latter requires a detailed understanding of the substituent effects (i.e. steric or electronic) on the chromophore light-induced dynamics. Below, we compare the results of QM/MM excited state trajectories of native and analogue-hosting microbial rhodopsins from the eubacterium Anabaena. The results uncover a relationship between nature of the substituent on the analogue (i.e. electron donating (a Me group) or withdrawing (a CF3 group)) and rhodopsin excited state lifetime. Most importantly, we show that electron donating or With drawing substituents cause a decrease or an increase in the electronic mixing of the first two excited states which, in turn, controls the photoisomerization speed.

show abstract

“…The charge delocalization caused red-shifts of retinal modified silk-elastin copolymer, but the hydrogen of the protonated Schiff base may not be distinguished by NMR spectra. 17,27 …”

Section: Resultsmentioning

confidence: 99%

“…17,18 Recently new retinal nano-ceramic thin films have been fabricated for photonic applications, and the Schiff base in the retinal films had a substantial effect on optical properties, suggesting a good candidate for holographic storage. 18 In the present study, silk-elastin-like polymers were synthesized and modified with retinal protonated Schiff Base, to generate an material for light-induced dynamic changes.…”

Section: Introductionmentioning

confidence: 99%

Photoresponsive Retinal-Modified Silk–Elastin Copolymer

et al. 2013

View full text Add to dashboard Cite

The chimeric proteins, silk-elastin-like protein polymers (SELPs), consist of repeating units of silk and elastin to retain the mechanical strength of silk, while incorporating the dynamic environmental sensitivity of elastin. A retinal-modified silk-elastin-like protein polymer was prepared, modified and studied for photodynamic responses. The protein was designed, cloned, expressed and purified with lysine present in the elastin repeats. The purified protein was then chemically modified with the bio-compatible moiety retinal via the lysine side chains. Structural changes with the polymer were assessed before and after retinal modification using Fourier Transform Infrared Spectroscopy and Circular Dichroism Spectroscopy. Optical studies and spectral analysis were performed before and after retinal-modification. The random coil fraction of the protein increased after retinal modification while the β-sheet fraction significantly decreased. Birefringence of the modified protein was induced when irradiated with a linearly polarized 488 nm laser light. Retinal modification of this protein offers a useful strategy for potential use in biosensors, controlled drug delivery and other areas of biomedical engineering.

show abstract

Backbone Modification of Retinal Induces Protein-like Excited State Dynamics in Solution

Cited by 44 publications

References 37 publications

Comparison of the isomerization mechanisms of human melanopsin and invertebrate and vertebrate rhodopsins

Comparison of the isomerization mechanisms of human melanopsin and invertebrate and vertebrate rhodopsins

Electronic State Mixing Controls the Photoreactivity of a Rhodopsin with all-trans Chromophore Analogues

Photoresponsive Retinal-Modified Silk–Elastin Copolymer

Contact Info

Product

Resources

About