chlorophyll-a has been researched along with sodium-thiocyanate* in 2 studies
2 other study(ies) available for chlorophyll-a and sodium-thiocyanate
Article | Year |
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Purification and properties of the intact P-700 and Fx-containing Photosystem I core protein.
The intact Photosystem I core protein, containing the psaA and psaB polypeptides, and electron transfer components P-700 through FX, was isolated from cyanobacterial and higher plant Photosystem I complexes with chaotropic agents followed by sucrose density ultracentrifugation. The concentrations of NaClO4, NaSCN, NaI, NaBr or urea required for the functional removal of the 8.9 kDa, FA/FB polypeptide was shown to be inversely related to the strength of the chaotrope. The Photosystem I core protein, which was purified to homogeniety, contains 4 mol of acid-labile sulfide and has the following properties: (i) the FX-containing core consists of the 82 and 83 kDa reaction center polypeptides but is totally devoid of the low-molecular-mass polypeptides; (ii) methyl viologen and other bipyridilium dyes have the ability to accept electrons directly from FX; (iii) the difference spectrum of FX from 400 to 900 nm is characteristic of an iron-sulfur cluster; (iv) the midpoint potential of FX, determined optically at room temperature, is 60 mV more positive than in the control; (v) there is indication by ESR spectroscopy of low-temperature heterogeneity within FX; and (vi) the heterogeneity is seen by optical spectroscopy as inefficiency in low-temperature electron flow to FX. The constraints imposed by the amount of non-heme iron and labile sulfide in the Photosystem I core protein, the cysteine content of the psaA and psaB polypeptides, and the stoichiometry of high-molecular-mass polypeptides, cause us to re-examine the possibility that FX is a [4Fe-4S] rather than a [2Fe-2S] cluster ligated by homologous cysteine residues on the psaA and psaB heterodimer. Topics: Bromides; Centrifugation, Density Gradient; Chlorates; Chlorophyll; Cold Temperature; Cross-Linking Reagents; Cyanobacteria; Digitonin; Electron Spin Resonance Spectroscopy; Electron Transport; Glutaral; Kinetics; Light-Harvesting Protein Complexes; Molecular Weight; Octoxynol; Oxidation-Reduction; Photochemistry; Photosynthetic Reaction Center Complex Proteins; Photosystem I Protein Complex; Plant Proteins; Polyethylene Glycols; Sodium; Sodium Compounds; Sodium Iodide; Spectrophotometry; Thiocyanates; Urea | 1989 |
Identification of a 19-kDa polypeptide as an Fe-S center apoprotein in the photosystem I primary electron acceptor complex.
Treatment of Photosystem I (PSI) with sodium thiocyanate, a chaotropic agent, results in the selective depletion of certain low-molecular-weight polypeptides. A PSI complex obtained following treatment with 0.5 M sodium thiocyanate is significantly depleted of polypeptides of approximately 8, 10, 14, and 16 kDa, relative to an untreated control, but retains approximately 90% of the EPR signal amplitude associated with the iron-sulfur Centers A and B. The only peptides remaining that could not be depleted without a parallel decrease in the signal amplitude of the Fe-S Centers A and B are the 62-kDa reaction center-containing polypeptide and a 19-kDa polypeptide. These results are considered in relation to the identity of the apoprotein of the Fe-S Centers A and B. Topics: Apoproteins; Chlorophyll; Densitometry; Electron Spin Resonance Spectroscopy; Electrophoresis, Polyacrylamide Gel; Iron-Sulfur Proteins; Light-Harvesting Protein Complexes; Metalloproteins; Molecular Weight; Peptides; Photosynthetic Reaction Center Complex Proteins; Photosystem I Protein Complex; Plant Proteins; Thiocyanates | 1985 |