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Updated: May 5, 2026

Purification of Active Photosystem I-Light Harvesting Complex I from Plant Tissues
Published on: February 3, 2023
Three iron-sulfur proteins encoded by three ORFs in chloroplasts and cyanobacteria
H Matsubara1, H Oh-Oka, Y Takahashi
1Department of Biochemistry, Faculty of Science, Okayama University of Science, 700, Okayama, Japan.
Abstract:
A brief review is presented on the gene products of frxA, frxB and frxC found in chloroplasts. The product of frxA shows high sequence homologies to bacterial 2[4Fe-4S] ferredoxins, but it functions as iron-sulfur centers A and B in Photosystem I, transferring electrons to [2Fe-2S] ferredoxin. This protein is located on surface of the thylakoid membranes in a state being covered by two other proteins. Proteins homologous to frxB product are found in mitochondrial respiratory Complex I and the product of frxB may function in chlororespiration, but at present no clear function of this protein is known. The frxC gene product is found to function in light-independent chlorophyll synthesis as one of the subunits of protochlorophyllide reductase and is reviewed in comparison to nitrogenase. Several problems and future research direction in these areas are also presented.
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