How to tune the absorption spectrum of chlorophylls to enable better use of the available solar spectrum
Photon capture by chlorophylls and other chromophores in light-harvesting complexes and photosystems is the driving force behind the light reactions of photosynthesis. Excitation of photosystem II allows it to receive electrons from the water-oxidizing oxygen-evolution complex and to transfer them t...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
PeerJ Inc.
2022-12-01
|
| Series: | PeerJ Physical Chemistry |
| Subjects: | |
| Online Access: | https://peerj.com/articles/pchem-26.pdf |
| _version_ | 1811288529305600000 |
|---|---|
| author | Pedro J. Silva Maria Osswald-Claro Rosário Castro Mendonça |
| author_facet | Pedro J. Silva Maria Osswald-Claro Rosário Castro Mendonça |
| author_sort | Pedro J. Silva |
| collection | DOAJ |
| description | Photon capture by chlorophylls and other chromophores in light-harvesting complexes and photosystems is the driving force behind the light reactions of photosynthesis. Excitation of photosystem II allows it to receive electrons from the water-oxidizing oxygen-evolution complex and to transfer them to an electron-transport chain that generates a transmembrane electrochemical gradient and ultimately reduces plastocyanin, which donates its electron to photosystem I. Subsequently, excitation of photosystem I leads to electron transfer to a ferredoxin which can either reduce plastocyanin again (in so-called “cyclical electron-flow”) and release energy for the maintenance of the electrochemical gradient, or reduce NADP+ to NADPH. Although photons in the far-red (700–750 nm) portion of the solar spectrum carry enough energy to enable the functioning of the photosynthetic electron-transfer chain, most extant photosystems cannot usually take advantage of them due to only absorbing light with shorter wavelengths. In this work, we used computational methods to characterize the spectral and redox properties of 49 chlorophyll derivatives, with the aim of finding suitable candidates for incorporation into synthetic organisms with increased ability to use far-red photons. The data offer a simple and elegant explanation for the evolutionary selection of chlorophylls a, b, c, and d among all easily-synthesized singly-substituted chlorophylls, and identified one novel candidate (2,12-diformyl chlorophyll a) with an absorption peak shifted 79 nm into the far-red (relative to chlorophyll a) with redox characteristics fully suitable to its possible incorporation into photosystem I (though not photosystem II). chlorophyll d is shown by our data to be the most suitable candidate for incorporation into far-red utilizing photosystem II, and several candidates were found with red-shifted Soret bands that allow the capture of larger amounts of blue and green light by light harvesting complexes. |
| first_indexed | 2024-04-13T03:38:50Z |
| format | Article |
| id | doaj.art-11624838ca184943bcbca3453167a1d4 |
| institution | Directory Open Access Journal |
| issn | 2689-7733 |
| language | English |
| last_indexed | 2024-04-13T03:38:50Z |
| publishDate | 2022-12-01 |
| publisher | PeerJ Inc. |
| record_format | Article |
| series | PeerJ Physical Chemistry |
| spelling | doaj.art-11624838ca184943bcbca3453167a1d42022-12-22T03:04:14ZengPeerJ Inc.PeerJ Physical Chemistry2689-77332022-12-014e2610.7717/peerj-pchem.26How to tune the absorption spectrum of chlorophylls to enable better use of the available solar spectrumPedro J. Silva0Maria Osswald-Claro1Rosário Castro Mendonça2UCIBIO@REQUIMTE, BioSIM, Departamento de Biomedicina, Faculdade de Medicina, Universidade do Porto, Porto, PortugalDeutsche Schule zu Porto, Porto, PortugalDeutsche Schule zu Porto, Porto, PortugalPhoton capture by chlorophylls and other chromophores in light-harvesting complexes and photosystems is the driving force behind the light reactions of photosynthesis. Excitation of photosystem II allows it to receive electrons from the water-oxidizing oxygen-evolution complex and to transfer them to an electron-transport chain that generates a transmembrane electrochemical gradient and ultimately reduces plastocyanin, which donates its electron to photosystem I. Subsequently, excitation of photosystem I leads to electron transfer to a ferredoxin which can either reduce plastocyanin again (in so-called “cyclical electron-flow”) and release energy for the maintenance of the electrochemical gradient, or reduce NADP+ to NADPH. Although photons in the far-red (700–750 nm) portion of the solar spectrum carry enough energy to enable the functioning of the photosynthetic electron-transfer chain, most extant photosystems cannot usually take advantage of them due to only absorbing light with shorter wavelengths. In this work, we used computational methods to characterize the spectral and redox properties of 49 chlorophyll derivatives, with the aim of finding suitable candidates for incorporation into synthetic organisms with increased ability to use far-red photons. The data offer a simple and elegant explanation for the evolutionary selection of chlorophylls a, b, c, and d among all easily-synthesized singly-substituted chlorophylls, and identified one novel candidate (2,12-diformyl chlorophyll a) with an absorption peak shifted 79 nm into the far-red (relative to chlorophyll a) with redox characteristics fully suitable to its possible incorporation into photosystem I (though not photosystem II). chlorophyll d is shown by our data to be the most suitable candidate for incorporation into far-red utilizing photosystem II, and several candidates were found with red-shifted Soret bands that allow the capture of larger amounts of blue and green light by light harvesting complexes.https://peerj.com/articles/pchem-26.pdfUV-vis spectrumChlorophyllsSynthetic biology applicationsTDDFT |
| spellingShingle | Pedro J. Silva Maria Osswald-Claro Rosário Castro Mendonça How to tune the absorption spectrum of chlorophylls to enable better use of the available solar spectrum PeerJ Physical Chemistry UV-vis spectrum Chlorophylls Synthetic biology applications TDDFT |
| title | How to tune the absorption spectrum of chlorophylls to enable better use of the available solar spectrum |
| title_full | How to tune the absorption spectrum of chlorophylls to enable better use of the available solar spectrum |
| title_fullStr | How to tune the absorption spectrum of chlorophylls to enable better use of the available solar spectrum |
| title_full_unstemmed | How to tune the absorption spectrum of chlorophylls to enable better use of the available solar spectrum |
| title_short | How to tune the absorption spectrum of chlorophylls to enable better use of the available solar spectrum |
| title_sort | how to tune the absorption spectrum of chlorophylls to enable better use of the available solar spectrum |
| topic | UV-vis spectrum Chlorophylls Synthetic biology applications TDDFT |
| url | https://peerj.com/articles/pchem-26.pdf |
| work_keys_str_mv | AT pedrojsilva howtotunetheabsorptionspectrumofchlorophyllstoenablebetteruseoftheavailablesolarspectrum AT mariaosswaldclaro howtotunetheabsorptionspectrumofchlorophyllstoenablebetteruseoftheavailablesolarspectrum AT rosariocastromendonca howtotunetheabsorptionspectrumofchlorophyllstoenablebetteruseoftheavailablesolarspectrum |