Antenna size dependence of fluorescence decay in the core antenna of photosystem I: estimates of charge separation and energy transfer rates.

The fluorescence quenching of a Zn(II) porphyrin linked to Cu(I) catenates relative to a model compound without Cu(I) was attributed to energy transfer from the Zn(II) porphyrin to the metal-to-ligand charge transfer (MLCT) state of the Cu(I) (phenanthroline)2 center at the core of the molecules. The similarity of the fluorescence spectra and fluorescence decays of a Zn(II) porphyrin linked to an Au(III) porphyrin, a Zn(II) porphyrin or a benzoate moiety through the catenate framework suggested that no fluorescence quenching by electron transfer to the Au(III) porphyrin occurred and that the copper(I) (phenanthroline)2 center acts as an energy sink. The value of the critical distance for Förster type energy transfer, determined from spectral data is compatible with the observed rate constants for energy transfer and dimensions of the macrocycle. The multi-exponential nature of the fluorescence decay is attributed to the presence of different slowly interconverting conformations of the macrocycle to which the porphyrins are attached.

Download Full-text

Excitation Energy Transfer in Mutants of Rb. sphaeroides: The Effects of Changes in the Core Antenna Size

Ultrafast Phenomena VIII - Springer Series in Chemical Physics ◽

10.1007/978-3-642-84910-7_177 ◽

1993 ◽

pp. 552-554 ◽

Cited By ~ 1

Author(s):

L. M. P. Beekman ◽

R. W. Visschers ◽

K. J. Visscher ◽

B. Althuis ◽

W. Barz ◽

...

Keyword(s):

Energy Transfer ◽

Excitation Energy ◽

Excitation Energy Transfer ◽

Antenna Size ◽

The Core

Download Full-text

Difference in light use strategy in red alga between Griffithsia pacifica and Porphyridium purpureum

Scientific Reports ◽

10.1038/s41598-021-93696-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mingyuan Xie ◽

Wenjun Li ◽

Hanzhi Lin ◽

Xiaoxiao Wang ◽

Jianwen Dong ◽

...

Keyword(s):

Energy Transfer ◽

Red Algae ◽

High Efficiency ◽

Fluorescence Decay ◽

Light Environment ◽

Low Light ◽

Porphyridium Purpureum ◽

Time Resolved ◽

Transfer Rates ◽

Light Harvesting Antenna

AbstractPhycobilisomes (PBSs) are the largest light-harvesting antenna in red algae, and feature high efficiency and rate of energy transfer even in a dim environment. To understand the influence of light on the energy transfer in PBSs, two red algae Griffithsia pacifica and Porphyridium purpureum living in different light environment were selected for this research. The energy transfer dynamics in PBSs of the two red algae were studied in time-resolved fluorescence spectroscopy in sub-picosecond resolution. The energy transfer pathways and the related transfer rates were uncovered by deconvolution of the fluorescence decay curve. Four time-components, i.e., 8 ps, 94 ps, 970 ps, and 2288 ps were recognized in the energy transfer in PBSs of G. pacifica, and 10 ps, 74 ps, 817 ps and 1292 ps in P. purpureum. In addition, comparison in energy transfer dynamics between the two red algae revealed that the energy transfer was clearly affected by lighting environment. The findings help us to understand the energy transfer mechanisms of red algae for adaptation to a natural low light environment.

Download Full-text