How carotenoid distortions may determine optical properties: lessons from the Orange Carotenoid Protein

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60076658%3A12310%2F19%3A43900389" target="_blank" >RIV/60076658:12310/19:43900389 - isvavai.cz</a>

Výsledek na webu

<a href="https://pubs.rsc.org/en/content/articlelanding/2019/CP/C9CP03574E#!divAbstract" target="_blank" >https://pubs.rsc.org/en/content/articlelanding/2019/CP/C9CP03574E#!divAbstract</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/c9cp03574e" target="_blank" >10.1039/c9cp03574e</a>

Jazyk výsledku

angličtina

Název v původním jazyce

How carotenoid distortions may determine optical properties: lessons from the Orange Carotenoid Protein

Popis výsledku v původním jazyce

Carotenoids in photosynthetic proteins carry out the dual function of harvesting light and defending against photo-damage by quenching excess energy. The latter involves the low-lying, dark, excited state labelled S-1. Here &quot;dark&quot; means optically-forbidden, a property that is often attributed to molecular symmetry, which leads to speculation that its optical properties may be strongly-perturbed by structural distortions. This has been both explicitly and implicitly proposed as an important feature of photo-protective energy quenching. Here we present a theoretical analysis of the relationship between structural distortions and S-1 optical properties. We outline how S-1 is dark not because of overall geometric symmetry but because of a topological symmetry related to bond length alternation in the conjugated backbone. Taking the carotenoid echinenone as an example and using a combination of molecular dynamics, quantum chemistry, and the theory of spectral lineshapes, we show that distortions that break this symmetry are extremely stiff. They are therefore absent in solution and only marginally present in even a very highly-distorted protein binding pocket such as in the Orange Carotenoid Protein (OCP). S-1 remains resolutely optically-forbidden despite any breaking of bulk molecular symmetry by the protein environment. However, rotations of partially conjugated end-rings can result in fine tuning of the S-1 transition density which may exert some influence on interactions with neighbouring chromophores.

Název v anglickém jazyce

How carotenoid distortions may determine optical properties: lessons from the Orange Carotenoid Protein

Popis výsledku anglicky

Carotenoids in photosynthetic proteins carry out the dual function of harvesting light and defending against photo-damage by quenching excess energy. The latter involves the low-lying, dark, excited state labelled S-1. Here &quot;dark&quot; means optically-forbidden, a property that is often attributed to molecular symmetry, which leads to speculation that its optical properties may be strongly-perturbed by structural distortions. This has been both explicitly and implicitly proposed as an important feature of photo-protective energy quenching. Here we present a theoretical analysis of the relationship between structural distortions and S-1 optical properties. We outline how S-1 is dark not because of overall geometric symmetry but because of a topological symmetry related to bond length alternation in the conjugated backbone. Taking the carotenoid echinenone as an example and using a combination of molecular dynamics, quantum chemistry, and the theory of spectral lineshapes, we show that distortions that break this symmetry are extremely stiff. They are therefore absent in solution and only marginally present in even a very highly-distorted protein binding pocket such as in the Orange Carotenoid Protein (OCP). S-1 remains resolutely optically-forbidden despite any breaking of bulk molecular symmetry by the protein environment. However, rotations of partially conjugated end-rings can result in fine tuning of the S-1 transition density which may exert some influence on interactions with neighbouring chromophores.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10301 - Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect)

Projekt

<a href="/cs/project/GA18-21631S" target="_blank" >GA18-21631S: Ultrarychlá časová spektroskopie jako nástroj pro studium vztahu mezi strukturou a funkcí karotenoproteinů u sinic</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physical Chemistry Chemical Physics

ISSN

1463-9076

e-ISSN

—

Svazek periodika

21

Číslo periodika v rámci svazku

41

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

11

Strana od-do

23187-23197

Kód UT WoS článku

000492992600051

EID výsledku v databázi Scopus

2-s2.0-85074117820