Low-Temperature Spectroscopic Properties of the Peridinin–Chlorophyll a–Protein (PCP) Complex from the Coral Symbiotic Dinoflagellate Symbiodinium

• Published in: The journal of physical chemistry. B Vol. 117; no. 38; pp. 11091 - 11099
• Main Authors: Niedzwiedzki, Dariusz M, Jiang, Jing, Lo, Cynthia S, Blankenship, Robert E
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 26.09.2013
• Subjects: Amphidinium carterae; Animals; Anthozoa; Biological and medical sciences; Carotenoids - chemistry; Chlorophyll - chemistry; Corals; Dinoflagellates; Dinoflagellida - metabolism; Energy Transfer; Excitation; Fittings; Formations; Fundamental and applied biological sciences. Psychology; Kinetics; Molecular biophysics; Nanostructure; Physico-chemical properties of biomolecules; Protozoan Proteins - chemistry; Protozoan Proteins - metabolism; Quantum Theory; SOLAR ENERGY; Spectrometry, Fluorescence; Spectroscopic analysis; Spectroscopy; Symbiodinium; Symbiosis; Temperature; Time Factors; Chlorophyll; Fluorescence; Molecular interaction; Kinetics; Time resolved spectra; Energy transfer; Protein; Absorption spectrum
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp401022u

The spectroscopic properties of the peridinin–chlorophyll a–protein (PCP) from the coral symbiotic dinoflagellate Symbiodinium have been characterized by application of various ultrafast optical spectroscopies including femto- and nanosecond time-resolved absorption and picosecond time-resolved fluorescence (TRF) at 77 K. Excited state properties of peridinin and Chl a and their intramolecular interaction characteristics have been obtained from global fitting analysis and directed kinetic modeling of the data sets and compared to their counterparts known for the PCP from Amphidinium carterae. The lifetimes of the excited state of peridinin show close agreement with those known for the counterpart PCP, demonstrating that molecular interactions have the same characteristics in both complexes. More variances have been recorded for the excited state properties of Chl a including elongation of both the intramolecular energy transfer time between Chl’s within the pair in the protein monomer and the excited state lifetime of the long wavelength form of Chl a (terminal acceptor). Kinetic modeling of formation of the peridinin triplet state has shown that the PCP is protected from potential photodamage due to an extremely fast peridinin triplet state formation of k TT = (14.4 ± 2.3) × 109 s–1 ((70 ± 12)−1 (ps)−1) that guarantees instantaneous depletion of Chl a triplets and prevents formation of harmful singlet oxygen (1ΔgO2).