dc.contributor.author
Götze, Jan P.
dc.contributor.author
Lokstein, Heiko
dc.date.accessioned
2023-11-16T13:55:23Z
dc.date.available
2023-11-16T13:55:23Z
dc.identifier.uri
https://refubium.fu-berlin.de/handle/fub188/41571
dc.identifier.uri
http://dx.doi.org/10.17169/refubium-41290
dc.description.abstract
Chlorophylls (Chls) are known for fast, subpicosecond internal conversion (IC) from ultraviolet/blue-absorbing (“B” or “Soret” states) to the energetically lower, red light-absorbing Q states. Consequently, excitation energy transfer (EET) in photosynthetic pigment–protein complexes involving the B states has so far not been considered. We present, for the first time, a theoretical framework for the existence of B–B EET in tightly coupled Chl aggregates such as photosynthetic pigment–protein complexes. We show that according to a Förster resonance energy transport (FRET) scheme, unmodulated B–B EET has an unexpectedly high range. Unsuppressed, it could pose an existential threat: the damage potential of blue light for photochemical reaction centers (RCs) is well-known. This insight reveals so far undescribed roles for carotenoids (Crts, this article) and Chl b (next article in this series) of possibly vital importance. Our model system is the photosynthetic antenna pigment–protein complex (CP29). Here, we show that the B → Q IC is assisted by the optically allowed Crt state (S2): The sequence is B → S2 (Crt, unrelaxed) → S2 (Crt, relaxed) → Q. This sequence has the advantage of preventing ∼39% of Chl–Chl B–B EET since the Crt S2 state is a highly efficient FRET acceptor. The B–B EET range and thus the likelihood of CP29 to forward potentially harmful B excitations toward the RC are thus reduced. In contrast to the B band of Chls, most Crt energy donation is energetically located near the Q band, which allows for 74/80% backdonation (from lutein/violaxanthin) to Chls. Neoxanthin, on the other hand, likely donates in the B band region of Chl b, with 76% efficiency. Crts thus act not only in their currently proposed photoprotective roles but also as a crucial building block for any system that could otherwise deliver harmful “blue” excitations to the RCs.
en
dc.format.extent
10 Seiten
dc.rights.uri
https://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subject
Chlorophylls
en
dc.subject
Excitation Energy Transfer
en
dc.subject
Photosynthetic Pigments
en
dc.subject.ddc
500 Naturwissenschaften und Mathematik::540 Chemie::541 Physikalische Chemie
dc.title
Excitation Energy Transfer between Higher Excited States of Photosynthetic Pigments: 1. Carotenoids Intercept and Remove B Band Excitations
dc.type
Wissenschaftlicher Artikel
dcterms.bibliographicCitation.doi
10.1021/acsomega.3c05895
dcterms.bibliographicCitation.journaltitle
ACS Omega
dcterms.bibliographicCitation.originalpublishername
American Chemical Society
dcterms.bibliographicCitation.pagestart
40005
dcterms.bibliographicCitation.pageend
40014
dcterms.bibliographicCitation.volume
8
dcterms.bibliographicCitation.url
https://doi.org/10.1021/acsomega.3c05895
refubium.affiliation
Biologie, Chemie, Pharmazie
refubium.affiliation.other
Institut für Chemie und Biochemie
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refubium.funding
Publikationsfonds FU
refubium.note.author
Die Publikation wurde aus Open Access Publikationsgeldern der Freien Universität Berlin gefördert.
de
refubium.resourceType.isindependentpub
no
dcterms.accessRights.openaire
open access
dc.relation.hascorrection
https://refubium.fu-berlin.de/handle/fub188/43885
dcterms.isPartOf.eissn
2470-1343