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
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