The role of NMR in the study of compounds of biological importance is widely recognized and appreciated. There can be few categories of such substances, however, to which NMR has made such substantive contributions as it has to the understanding of the chlorophylls and the corrins. The chlorophylls are indispensible agents in the conversion of the energy of light to chemical oxidizing and reduc...

We compare the chlorophyll fluorescence decay kinetics of the wild type and the D2-H117N mutant photosystem II reaction centers isolated from Chlamydomonas reinhardtii. The histidine residue located at site 117 on the D2 polypeptide of photosystem II is a proposed binding site for one of two peripheral accessory chlorophylls located in the reaction center complex. The peripheral accessory chlor...

Extraction of compounds from microalgae requires cell disruption as a pretreatment to increase extraction yield. Botryococcus braunii is a microalga with a significant content of carotenoids and other antioxidant compounds, such as chlorophylls. Cell disruption of B. braunii using CO2 rapid depressurization was studied as a pretreatment for the extraction of carotenoid and chlorophyll pigments....

We report for the first time steady-state and time-resolved emission properties of photosystem I (PSI) complexes isolated from the cyanobacterial strain Synechococcus WH 7803. The PSI complexes from this strain display an extremely small fluorescence emission yield at 77 K, which we attribute to the absence of so-called red antenna chlorophylls, chlorophylls with absorption maxima at wavelength...

Brassica oleracea vegetables, such as broccoli (B. oleracea L. var. italica) and cauliflower (B. oleracea L. var. botrytis), are known to contain bioactive compounds associated with health, including three classes of photosynthetic lipid-soluble compounds: carotenoids, chlorophylls, and tocopherols. Carotenoids and chlorophylls are photosynthetic pigments. Tocopherols have vitamin E activity. D...

Chlorophotoautotrophy, the use of chlorophylls to convert light energy into chemical energy for carbon dioxide fixation, is the primary metabolic process linking the inorganic and organic carbon pools on Earth. To understand the potential effects of various environmental constraints on the evolution of chlorophototrophy better, we studied the distribution, diversity, and abundance of chlorophyl...

Lhc proteins constitute a family of transmembrane proteins which share homology in sequence and similarity in the general organisation although members can be strongly differentiated such as in the case of PsbS and ELIPs. In this work, we report on the structure of Lhca3, a pigment-protein subunit component of the antenna system of higher plants Photosystem I, through the effect of point mutati...

Chlorophylls are a fundamental class of tetrapyrroles and function as the central reaction center, accessory and photoprotective pigments in photosynthesis. Their unique individual photochemical properties are a consequence of the tetrapyrrole macrocycle, the structural chemistry and coordination behavior of the phytochlorin system, and specific substituent pattern. They achieve their full pote...

We have probed the absorption changes due to an externally applied electric field (Stark effect) of Photosystem I (PSI) core complexes from the cyanobacteria Synechocystis sp. PCC 6803, Synechococcus elongatus and Spirulina platensis. The results reveal that the so-called C719 chlorophylls in S. elongatus and S. platensis are characterized by very large polarizability differences between the gr...