Biomaterial Database

The 110-kDa reaction center protein of photosystem I, P700-chlorophyll a-protein 1, is an iron-sulfur protein. 1986

P B Høj, and B L Møller

Germination and growth of barley (Hordeum vulgare L.) in the presence of 59Fe2+ or 35SO4(2-) allows heavy incorporation of both isotopes into the thylakoid membranes and into isolated photosystem I particles. Analysis of 59Fe-labeled preparations by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under mild conditions demonstrates that a minimum of four iron atoms/P700 is carried on P700-chlorophyll a-protein 1. When isolated from 35S-labeled preparations, P700-chlorophyll a-protein 1 binds zero valence 35S, which is converted into acid-labile [35S]sulfide by dithiothreitol reduction. Isolated photosystem I particles contain 14 acid-labile sulfide atoms and 10 iron atoms for each molecule of P700 and are composed of polypeptides of 110, 18, 15, 10, and 8 kDa of which the 10-kDa component is loosely bound. Under the electrophoretic conditions used, none of the low molecular weight polypeptides could be shown to be specifically associated with iron or acid-labile sulfide. Carboxymethylation of cysteine residues shows a high cysteine content in the 8-kDa polypeptide and an intermediate content in the 110- and 18-kDa polypeptides, whereas the 15-kDa polypeptide is devoid of sulfur amino acids. The experiments with the 59Fe-labeled thylakoids reveal other labeled polypeptides not associated with photosystem I, namely cytochrome f and possibly cytochromes b6 and b559.

UI	MeSH Term	Description	Entries
D007506	Iron-Sulfur Proteins	A group of proteins possessing only the iron-sulfur complex as the prosthetic group. These proteins participate in all major pathways of electron transport: photosynthesis, respiration, hydroxylation and bacterial hydrogen and nitrogen fixation.	Iron-Sulfur Protein,Iron Sulfur Proteins,Iron Sulfur Protein,Protein, Iron-Sulfur,Proteins, Iron Sulfur,Proteins, Iron-Sulfur,Sulfur Proteins, Iron
D008667	Metalloproteins	Proteins that have one or more tightly bound metal ions forming part of their structure. (Dorland, 28th ed)	Metalloprotein
D010940	Plant Proteins	Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which PLANT PROTEINS, DIETARY is available.	Plant Protein,Protein, Plant,Proteins, Plant
D002734	Chlorophyll	Porphyrin derivatives containing magnesium that act to convert light energy in photosynthetic organisms.	Phyllobilins,Chlorophyll 740
D004229	Dithiothreitol	A reagent commonly used in biochemical studies as a protective agent to prevent the oxidation of SH (thiol) groups and for reducing disulphides to dithiols.	Cleland Reagent,Cleland's Reagent,Sputolysin,Clelands Reagent,Reagent, Cleland,Reagent, Cleland's
D004591	Electrophoresis, Polyacrylamide Gel	Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.	Polyacrylamide Gel Electrophoresis,SDS-PAGE,Sodium Dodecyl Sulfate-PAGE,Gel Electrophoresis, Polyacrylamide,SDS PAGE,Sodium Dodecyl Sulfate PAGE,Sodium Dodecyl Sulfate-PAGEs
D000077194	Chlorophyll A	A form of chlorophyll that absorbs light in the violet to red spectrum (approximately 400-700 nm wavelength range) and reflects green light (500-570 nm wavelength), which imparts the characteristic green color to land plants. It is essential for oxygenic PHOTOSYNTHESIS.	Chlorophyll A2
D001467	Hordeum	A plant genus of the family POACEAE. The EDIBLE GRAIN, barley, is widely used as food.	Barley,Hordeum vulgare
D045322	Photosynthetic Reaction Center Complex Proteins	Protein complexes that take part in the process of PHOTOSYNTHESIS. They are located within the THYLAKOID MEMBRANES of plant CHLOROPLASTS and a variety of structures in more primitive organisms. There are two major complexes involved in the photosynthetic process called PHOTOSYSTEM I and PHOTOSYSTEM II.	Photosynthetic Complex,Photosynthetic Reaction Center,Photosynthetic Reaction Center Complex Protein,Photosynthetic Complexes,Photosynthetic Reaction Centers,Center, Photosynthetic Reaction,Complex, Photosynthetic,Complexes, Photosynthetic,Reaction Center, Photosynthetic,Reaction Centers, Photosynthetic
D045331	Photosystem I Protein Complex	A large multisubunit protein complex that is found in the THYLAKOID MEMBRANE. It uses light energy derived from LIGHT-HARVESTING PROTEIN COMPLEXES to drive electron transfer reactions that result in either the reduction of NADP to NADPH or the transport of PROTONS across the membrane.	Photosystem I Reaction Center,Photosystem I