Characterization of Nucleotide Binding Sites of the Isolated H+-ATPase from Spinach Chloroplasts, CF0F1
| Autor: | Franziska E. Possmayer, Helena M. Scofano, Tânia Beatriz Creczynski-Pasa, Peter Gräber |
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| Rok vydání: | 2000 |
| Předmět: |
chemistry.chemical_classification
Binding Sites Chloroplasts biology ATPase Biophysics Biochemistry Adenosine Diphosphate Chloroplast Kinetics Proton-Translocating ATPases Hydrolysis Adenosine Triphosphate Enzyme chemistry Spinacia oleracea Covalent bond ATP hydrolysis Catalytic Domain biology.protein Nucleotide Binding site Molecular Biology |
| Zdroj: | Archives of Biochemistry and Biophysics. 376:141-148 |
| ISSN: | 0003-9861 |
| Popis: | Soluble purified CF(0)F(1) from chloroplasts was either oxidized or reduced and then incubated with [alpha-(32)P]ATP in the presence or in the absence of Mg(2+). Depending on the conditions of incubation, the enzyme showed different tight-nucleotide binding sites. In the presence of EDTA, two sites bind [alpha-(32)P]ATP from the reaction medium at different rates. Both sites promote ATP hydrolysis, since equimolar amounts of [alpha-(32)P]ATP and [alpha-(32)P]ADP are bound to the enzyme. In the presence of Mg(2+), only one site appears during the first hour of incubation, with characteristics similar to those described in the absence of Mg(2+). However, after this time a third site appears also permitting binding of ATP from the reaction medium, but in this case the bound ATP is not hydrolyzed. Covalent derivatization by 2-azido-[alpha-(32)P]ATP was used to distinguish between catalytic and noncatalytic sites. In the presence of Mg(2+), there are at least three distinct nucleotide binding sites that bind nucleotide tightly from the reaction medium: two of them are catalytic and one is noncatalytic. |
| Databáze: | OpenAIRE |
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