Absorption and Fluorescence Properties of Highly Enriched Reaction Center Particles of Photosystem I and of Artificial Systems
نویسنده
چکیده
The absorption and fluorescence characteristics of subchloroplast particles highly enriched in P700 (1 P700 to 10-15 chlorophyll a molecules) and of two artificial systems are presented here. The fluorescence characteristics measured were excitation and emission spectra, and the degree of polarization of fluorescence. The model systems studied were chlorophyll a and pheophytin a in a polystyrene matrix, and a colloidal mixture of these two pigments with bovine serum albumin. Effects of 0.5% sodium dodecyl sulfate on the optical properties of the P7Wenriched particles are also described. The importance of pigment-pigment and pigment-protein interactions in determining the fluorescence properties of these particles are discussed. The possible role of pheophytin in these preparations needs further investigation.
منابع مشابه
Evidence of monomeric photosystem I complexes and phosphorylation of chlorophyll a/c-binding polypeptides in Chroomonas sp. strain LT (Cryptophyceae).
Thylakoid membranes of the cryptophyte Chroomonas sp. strain LT were solubilized with dodecyl-beta-maltoside and subjected to sucrose density gradient centrifugation. The four pigment protein complexes obtained were subsequently characterized by absorption and fluorescence spectroscopy, SDS-PAGE, and Western immunoblotting using antisera against the chlorophyll a/c-binding proteins of the marin...
متن کاملChlorophyll proteins of photosystem I.
Data are presented which suggest the existence of a light-harvesting pigment-protein complex which is functionally and structurally associated with photosystem I (PSI) reaction centers. These observations are based on techniques which allow isolation of PSI using minimal concentrations of Triton X-100. Properties of density and self aggregation allowed purification of a "native" PSI complex.The...
متن کاملRelationship between excitation energy transfer, trapping, and antenna size in photosystem II.
We present a systematic study of the effect of antenna size on energy transfer and trapping in photosystem II. Time-resolved fluorescence experiments have been used to probe a range of particles isolated from both higher plants and the cyanobacterium Synechocystis 6803. The isolated reaction center dynamics are represented by a quasi-phenomenological model that fits the extensive time-resolved ...
متن کاملPurification and spectroscopic characterization of photosystem II reaction center complexes isolated with or without Triton X-100.
The pigment composition of the isolated photosystem II reaction center complex in its most stable and pure form currently is a matter of considerable debate. In this contribution, we present a new method based on a combination of gel filtration chromatography and diode array detection to analyze the composition of photosystem II reaction center preparations. We show that the method is very sens...
متن کاملAntenna size dependence of fluorescence decay in the core antenna of photosystem I: estimates of charge separation and energy transfer rates.
We have examined the photophysics of energy migration and trapping in photosystem I by investigating the spectral and temporal properties of the fluorescence from the core antenna chlorophylls as a function of the antenna size. Time-correlated single photon counting was used to determine the fluorescence lifetimes in the isolated P700 chlorophyll a-protein complex and in a mutant of Chlamydomon...
متن کامل