Reversed-phase HPLC Determination of Chlorophyll a' and Naphthoquinones in Photosystem I of Red Algae

Chlorophyll (Chl) a', the C132-epimer of Chl a, is one of the two Chl molecules constituting the primary electron donor (P700) of photosystem (PS) I of a thermophilic cyanobacterium Synechococcus elongatus. To examine whether PS I of other oxygenic photosynthetic organisms in general contain on...

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Bibliographic Details
Published in:Analytical sciences 2003-07, Vol.19 (7), p.1001
Main Authors: YOSHIDA, Emi, NAKAMURA, Akimasa, WATANABE, Tadashi
Format: Article
Language:English
Subjects:
Algae
Chlorophyll
Liquid chromatography
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Summary:Chlorophyll (Chl) a', the C132-epimer of Chl a, is one of the two Chl molecules constituting the primary electron donor (P700) of photosystem (PS) I of a thermophilic cyanobacterium Synechococcus elongatus. To examine whether PS I of other oxygenic photosynthetic organisms in general contain one Chl a' molecule in P700, the pigment composition of thylakoid membranes and PS I preparations isolated from red algae Porphyridium purpureum and Cyanidium caldarium was examined by reversed-phase HPLC with particular attention to Chl a' and phylloquinone (PhQ), the secondary electron acceptor of PS I. The two red algae contained one Chl a' molecule at the core part of PS I. In PS I of C. caldarium, two menaquinone-4 (MQ-4) molecules were detected in place of PhQ used by higher plants and cyanobacteria. The 1:2:1 stoichiometry among Chl a', PhQ (MQ-4) and P700 in PS I of the red algae indicates that one Chl a' molecule universally exists in PS I of oxygenic photosynthetic organisms, and two MQ-4 molecules are associated with PS I of C. caldarium.
ISSN:0910-6340
1348-2246