{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T15:58:27Z","timestamp":1791475107156,"version":"4.3.4"},"reference-count":41,"publisher":"American Chemical Society (ACS)","issue":"40","license":[{"start":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T00:00:00Z","timestamp":1790035200000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-029"},{"start":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T00:00:00Z","timestamp":1790035200000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-037"},{"start":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T00:00:00Z","timestamp":1790035200000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-045"}],"funder":[{"DOI":"10.13039\/100006151","name":"Basic Energy Sciences","doi-asserted-by":"publisher","award":["DE-FG02-99ER20350"],"award-info":[{"award-number":["DE-FG02-99ER20350"]}],"id":[{"id":"10.13039\/100006151","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,10,8]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Iron-stress-induced protein A (IsiA) is a chlorophyll (Chl) a-containing protein in cyanobacteria. Under low-iron growth, it is the most abundant intracellular Chl a-binding protein. IsiA and the CP43 protein are suggested to have coevolved from a common ancestral protein, sharing similar spectroscopic properties. When expressed, IsiA forms IsiA-only and photosystem I (PSI)-IsiA complexes. The IsiA-only complex shows a cysteine-mediated photoprotective mechanism that partially mitigates the risk of photo-oxidative damage by quenching Chl a singlet excitation. However, the effectiveness of longer-time-scale photoprotection, such as Chl a\u202f\u2192\u202fcarotenoid triplet\u2013triplet sensitization (TTS), remains unknown. Our evaluation suggests an extraordinarily slow TTS with a time constant of 100 ns. This is comparable to the concurrent sensitization of singlet oxygen. From this perspective, the photoprotective role of carotenoids in IsiA is underperforming. Therefore, a cysteine-based Chl a quenching could be seen as a supplementary photoprotective mechanism, developed specifically to complement underperforming Chl a\u202f\u2192\u202fcarotenoid TTS.<\/jats:p>","DOI":"10.1021\/acs.jpclett.6c02712","type":"journal-article","created":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T04:02:03Z","timestamp":1790136123000},"page":"11406-11412","source":"Crossref","is-referenced-by-count":0,"title":["Inefficient\nCarotenoid-Mediated Quenching of Chlorophyll\n                    <i>a<\/i>\n                    Triplet:\nA Hypothetical Cause for the Evolution of Cys-Mediated\nQuenching in IsiA"],"prefix":"10.1021","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1976-9296","authenticated-orcid":true,"given":"Dariusz M.","family":"Niedzwiedzki","sequence":"first","affiliation":[{"name":"Washington University , , , ,","place":["St. Louis, Missouri, United States, 63130"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9718-8948","authenticated-orcid":true,"given":"Sandeep","family":"Biswas","sequence":"additional","affiliation":[{"name":"Washington University , , , ,","place":["St. Louis, Missouri, United States, 63130"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8240-2123","authenticated-orcid":true,"given":"Himadri B.","family":"Pakrasi","sequence":"additional","affiliation":[{"name":"Washington University , , , ,","place":["St. Louis, Missouri, United States, 63130"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2026,9,22]]},"reference":[{"issue":"11","key":"2026100811155594500_cit1","doi-asserted-by":"publisher","first-page":"5018","DOI":"10.1128\/jb.170.11.5018-5026.1988","article-title":"Characterization of a cyanobacterial iron stress-induced\ngene similar to psbC","volume":"170","author":"Laudenbach","year":"1988","journal-title":"J. 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Ecol."},{"issue":"1","key":"2026100811155594500_cit5","doi-asserted-by":"publisher","first-page":"12","DOI":"10.1039\/C9EM00415G","article-title":"Photochemistry of iron\nin aquatic environments","volume":"22","author":"Lueder","year":"2020","journal-title":"Environ. Sci. Process\nImpacts"},{"issue":"6848","key":"2026100811155594500_cit6","doi-asserted-by":"publisher","first-page":"743","DOI":"10.1038\/35089098","article-title":"Iron deficiency induces the formation\nof an antenna ring around trimeric photosystem I in cyanobacteria","volume":"412","author":"Bibby","year":"2001","journal-title":"Nature"},{"key":"2026100811155594500_cit7","doi-asserted-by":"publisher","first-page":"143","DOI":"10.1016\/j.molp.2016.10.009","article-title":"Dynamic changes\nof\nIsiA-containing complexes during long-term Iron deficiency in Synechocystis sp. PCC 6803","volume":"10","author":"Ma","year":"2017","journal-title":"Mol. Plant"},{"issue":"3","key":"2026100811155594500_cit8","doi-asserted-by":"publisher","first-page":"893","DOI":"10.1104\/pp.103.3.893","article-title":"The highly\nabundant chlorophyll-protein\ncomplex of iron-deficient Synechococcus sp. PCC7942\n(CP43\u2019) is encoded by the isiA gene","volume":"103","author":"Burnap","year":"1993","journal-title":"Plant Physiol."},{"issue":"26","key":"2026100811155594500_cit9","doi-asserted-by":"publisher","first-page":"15244","DOI":"10.1073\/pnas.93.26.15244","article-title":"Independent evolution of the prochlorophyte and green plant chlorophyll a\/b light-harvesting proteins","volume":"93","author":"La Roche","year":"1996","journal-title":"Proc. Natl. Acad. Sci. U. S. A."},{"issue":"46","key":"2026100811155594500_cit10","doi-asserted-by":"publisher","first-page":"43246","DOI":"10.1074\/jbc.M106541200","article-title":"Three-dimensional\nmodel and characterization\nof the iron stress-induced CP43\u2019-photosystem I supercomplex\nisolated from the cyanobacterium Synechocystis PCC\n6803","volume":"276","author":"Bibby","year":"2001","journal-title":"J. Biol. Chem."},{"issue":"32","key":"2026100811155594500_cit11","doi-asserted-by":"publisher","first-page":"10308","DOI":"10.1021\/bi048772l","article-title":"Supramolecular organization\nand dual function of the IsiA chlorophyll-binding protein in cyanobacteria","volume":"43","author":"Yeremenko","year":"2004","journal-title":"Biochemistry"},{"issue":"6","key":"2026100811155594500_cit12","doi-asserted-by":"publisher","first-page":"443","DOI":"10.1038\/s41594-019-0228-8","article-title":"The structure of the\nstress-induced photosystem I\u2013IsiA antenna supercomplex","volume":"26","author":"Toporik","year":"2019","journal-title":"Nat. Struct. Mol. Biol."},{"issue":"1","key":"2026100811155594500_cit13","doi-asserted-by":"publisher","first-page":"4650","DOI":"10.1038\/s41467-023-40146-8","article-title":"Energetic robustness\nto large scale structural fluctuations in a photosynthetic supercomplex","volume":"14","author":"Harris","year":"2023","journal-title":"Nat. Commun."},{"issue":"2","key":"2026100811155594500_cit14","doi-asserted-by":"publisher","first-page":"167","DOI":"10.1038\/s41477-020-0593-7","article-title":"Structural\nbasis for energy and electron\ntransfer of the photosystem I\u2013IsiA\u2013flavodoxin supercomplex","volume":"6","author":"Cao","year":"2020","journal-title":"Nature Plants"},{"issue":"1","key":"2026100811155594500_cit15","doi-asserted-by":"publisher","first-page":"232","DOI":"10.1038\/s42003-020-0949-6","article-title":"Structure of a cyanobacterial\nphotosystem I surrounded\nby octadecameric IsiA antenna proteins","volume":"3","author":"Akita","year":"2020","journal-title":"Commun.\nBiol."},{"issue":"1","key":"2026100811155594500_cit16","doi-asserted-by":"publisher","first-page":"920","DOI":"10.1038\/s41467-023-36504-1","article-title":"Structure\nof a monomeric photosystem I core\nassociated with iron-stress-induced-A proteins from Anabaena sp. PCC 7120. 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B"},{"issue":"32","key":"2026100811155594500_cit19","doi-asserted-by":"publisher","first-page":"10846","DOI":"10.1021\/bi0510680","article-title":"Aggregates\nof the chlorophyll-binding protein IsiA (CP43\u2032) dissipate energy\nin cyanobacteria","volume":"44","author":"Ihalainen","year":"2005","journal-title":"Biochemistry"},{"issue":"13","key":"2026100811155594500_cit20","doi-asserted-by":"publisher","first-page":"3893","DOI":"10.1021\/bi026987u","article-title":"Time-resolved\nabsorption and emission show that the CP43\u2019 antenna ring of\niron-stressed Synechocystis sp. PCC6803 is efficiently\ncoupled to the photosystem I reaction center core","volume":"42","author":"Melkozernov","year":"2003","journal-title":"Biochemistry"},{"issue":"2\u20133","key":"2026100811155594500_cit21","doi-asserted-by":"publisher","first-page":"265","DOI":"10.1016\/S0005-2728(02)00371-7","article-title":"Spectroscopic properties\nof PSI-IsiA supercomplexes from the cyanobacterium Synechococcus PCC 7942","volume":"1556","author":"Andrizhiyevskaya","year":"2002","journal-title":"Biochim. Biophys. Acta Bioenerg."},{"issue":"3","key":"2026100811155594500_cit22","doi-asserted-by":"publisher","first-page":"771","DOI":"10.1021\/acsfoodscitech.5c01168","article-title":"Digital database\nof absorption spectra\nof carotenoids found in food and photosynthetic organisms","volume":"6","author":"Niedzwiedzki","year":"2026","journal-title":"ACS Food Sci. 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Phys."},{"issue":"6","key":"2026100811155594500_cit28","doi-asserted-by":"publisher","first-page":"2261","DOI":"10.1016\/j.bpj.2008.12.3905","article-title":"A mechanism of energy dissipation\nin cyanobacteria","volume":"96","author":"Berera","year":"2009","journal-title":"Biophys. J."},{"issue":"31","key":"2026100811155594500_cit29","doi-asserted-by":"publisher","first-page":"E4486","DOI":"10.1073\/pnas.1603330113","article-title":"Evidence\nfor a cysteine-mediated mechanism of excitation energy regulation\nin a photosynthetic antenna complex","volume":"113","author":"Orf","year":"2016","journal-title":"Proc. Natl.\nAcad. Sci. U. S. A."},{"issue":"3","key":"2026100811155594500_cit30","doi-asserted-by":"publisher","first-page":"249","DOI":"10.1016\/j.bbabio.2017.01.001","article-title":"Reevaluating\nthe mechanism of excitation energy regulation in iron-starved cyanobacteria","volume":"1858","author":"Chen","year":"2017","journal-title":"Biochim. Biophys. Acta Bioenerg."},{"issue":"1","key":"2026100811155594500_cit31","doi-asserted-by":"publisher","DOI":"10.1128\/mBio.03663-20","article-title":"A novel mode of photoprotection mediated by a cysteine\nresidue in\nthe chlorophyll protein IsiA","volume":"12","author":"Chen","year":"2021","journal-title":"mBio"},{"issue":"38","key":"2026100811155594500_cit32","doi-asserted-by":"publisher","first-page":"11091","DOI":"10.1021\/jp401022u","article-title":"Low-temperature\nspectroscopic properties of the peridinin\u2013chlorophyll a\u2013protein\n(pcp) complex from the coral symbiotic dinoflagellate Symbiodinium","volume":"117","author":"Niedzwiedzki","year":"2013","journal-title":"J. Phys. Chem. B"},{"issue":"4","key":"2026100811155594500_cit33","doi-asserted-by":"publisher","first-page":"341","DOI":"10.1016\/j.bbabio.2016.01.008","article-title":"Triplet\u2013triplet energy transfer\nfrom chlorophylls to carotenoids in two antenna complexes from dinoflagellate Amphidinium carterae","volume":"1857","author":"Kvi\u0301c\u030calova\u0301","year":"2016","journal-title":"Biochim. Biophys.Acta\nBioenerg."},{"issue":"6","key":"2026100811155594500_cit34","doi-asserted-by":"publisher","first-page":"3143","DOI":"10.1016\/S0006-3495(98)77756-2","article-title":"Rate of carotenoid\ntriplet formation in solubilized light-harvesting complex ii (LHCII)\nfrom spinach","volume":"75","author":"Scho\u0308del","year":"1998","journal-title":"Biophys. J."},{"issue":"15","key":"2026100811155594500_cit35","doi-asserted-by":"publisher","first-page":"3253","DOI":"10.1016\/j.febslet.2005.03.051","article-title":"Structure and functional role of\nsupercomplexes of\nIsiA and Photosystem I in cyanobacterial photosynthesis","volume":"579","author":"Kouril","year":"2005","journal-title":"FEBS Lett."},{"issue":"2","key":"2026100811155594500_cit36","doi-asserted-by":"publisher","first-page":"346","DOI":"10.1016\/j.jphotochem.2008.08.006","article-title":"Photophysical characterization\nof imidazolium-substituted Pd(II), In(III), and Zn(II) porphyrins\nas photosensitizers for photodynamic therapy","volume":"200","author":"Kee","year":"2008","journal-title":"J. Photochem. Photobiol., A"},{"issue":"6","key":"2026100811155594500_cit37","doi-asserted-by":"publisher","first-page":"533","DOI":"10.1111\/j.1751-1097.1980.tb03742.x","article-title":"Kinetic and spectroscopic\nfeatures of some carotenoid\ntriplet states: Sensitization by singlet oxygen","volume":"31","author":"Rodgers","year":"1980","journal-title":"Photochem. Photobiol."},{"issue":"29","key":"2026100811155594500_cit38","doi-asserted-by":"publisher","first-page":"6058","DOI":"10.1021\/acs.jafc.7b01616","article-title":"Singlet fission\nreaction of light-exposed \u03b2-carotene\nbound to bovine serum albumin. A novel mechanism in protection of\nlight-exposed tissue by dietary carotenoids","volume":"65","author":"Chang","year":"2017","journal-title":"J. Agric. Food Chem."},{"issue":"6","key":"2026100811155594500_cit39","doi-asserted-by":"publisher","first-page":"814","DOI":"10.1016\/j.bbabio.2006.11.015","article-title":"A role for mrgA,\na DPS family protein, in the internal transport of Fe in the cyanobacterium Synechocystis sp. PCC6803","volume":"1767","author":"Shcolnick","year":"2007","journal-title":"Biochim.\nBiophys. Acta Bioenerg."},{"issue":"7","key":"2026100811155594500_cit40","doi-asserted-by":"publisher","DOI":"10.1016\/j.bbabio.2022.148580","article-title":"Introduction of cysteine-mediated\nquenching in the CP43 protein of photosystem II builds resilience\nto high-light stress in a cyanobacterium","volume":"1863","author":"Biswas","year":"2022","journal-title":"Biochim.\nBiophys. Acta Bioenerg."},{"issue":"1447","key":"2026100811155594500_cit41","doi-asserted-by":"publisher","first-page":"435","DOI":"10.1098\/rspa.1967.0036","article-title":"Quantum yields of triplet\nformation in solutions of\nchlorophyll","volume":"296","author":"Bowers","year":"1967","journal-title":"Proc. R. Soc. London Ser. A Math.\nPhys. Sci."}],"container-title":["The Journal of Physical\nChemistry Letters"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pubs.acs.org\/doi\/pdf\/10.1021\/acs.jpclett.6c02712","content-type":"application\/pdf","content-version":"vor","intended-application":"unspecified"},{"URL":"https:\/\/pubs.acs.org\/jpclcd\/article-pdf\/17\/40\/11406\/68611559\/acs.jpclett.6c02712.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pubs.acs.org\/jpclcd\/article-pdf\/17\/40\/11406\/68611559\/acs.jpclett.6c02712.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T15:31:22Z","timestamp":1791473482000},"score":1,"resource":{"primary":{"URL":"https:\/\/pubs.acs.org\/jpclcd\/article\/17\/40\/11406\/5436042\/Inefficient-Carotenoid-Mediated-Quenching-of"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,22]]},"references-count":41,"journal-issue":{"issue":"40","published-online":{"date-parts":[[2026,9,22]]},"published-print":{"date-parts":[[2026,10,8]]}},"URL":"https:\/\/doi.org\/10.1021\/acs.jpclett.6c02712","relation":{},"ISSN":["1948-7185"],"issn-type":[{"value":"1948-7185","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,22]]}}}