Open AccessThe Role of Acidic Residues in the C Terminal Tail of the LHCSR3 Protein of Chlamydomonas reinhardtii in Non-Photochemical Quenching
Author(s) -
Franco V. A. Camargo,
Federico Perozeni,
Gabriel de la Cruz Valbuena,
Luca Zuliani,
Samim Sardar,
Giulio Cerullo,
Cosimo D’Andrea,
Matteo Ballottari
Publication year - 2021
Publication title -
the journal of physical chemistry letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.563
H-Index - 203
ISSN - 1948-7185
DOI - 10.1021/acs.jpclett.1c01382
Subject(s) - chlamydomonas reinhardtii , photoprotection , quenching (fluorescence) , chemistry , non photochemical quenching , biophysics , protonation , chloroplast , photochemistry , light harvesting complex , chlamydomonas , biochemistry , fluorescence , photosynthesis , xanthophyll , photosystem ii , biology , ion , physics , organic chemistry , quantum mechanics , mutant , gene
Light-harvesting complex stress-related (LHCSR) proteins in green algae are essential for photoprotection via a non-photochemical quenching (NPQ), playing the dual roles of pH sensing and dissipation of chlorophylls excited-state energy. pH sensing occurs via a protonation of acidic residues located mainly on its lumen-exposed C-terminus. Here, we combine in vivo and in vitro studies to ascertain the role in NPQ of these protonatable C-terminal residues in LHCSR3 from Chlamydomonas reinhardtii . In vivo studies show that four of the residues, D239, D240, E242, and D244, are not involved in NPQ. In vitro experiments on an LHCSR3 chimeric protein, obtained by a substitution of the C terminal with that of another LHC protein lacking acidic residues, show a reduction of NPQ compared to the wild type but preserve the quenching mechanism involving a charge transfer from carotenoids to chlorophylls. NPQ in LHCSR3 is thus a complex mechanism, composed of multiple contributions triggered by different acidic residues.