| Autor: |
Wagner, Richard, Apley, Enno C., Engelbrecht, Siegfried, Junge, Wolfgang |
| Zdroj: |
FEBS Letters; January 1988, Vol. 230 Issue: 1 p109-115, 7p |
| Abstrakt: |
We investigated the binding of subunit δ to solubilized chloroplast ATPase. Purified δ was covalently labeled with eosin 5-isothiocyanate and its rotational correlation time was determined by a photoselection technique as a function of added CF 1(containing δ) and of CF 1(−δ) (lacking δ). In aqueous buffer the rotational correlation time of labeled δ was 33 ns. This is compatible with a rather elongated shape with the dimensions 2 b= 100 Å/2 a= 28 Å. Binding of δ to CF 1decreased the rotational correlation time about 10-fold. The result was a biphasic decay of the laser flash-induced absorption anisotropy which was analyzed to yield the proportion of δ (bound to CF 1) relative to δ (free). CF 1(−δ), which completely lacked the δ-subunit, bound one δ (mol/mol) with high affinity ( Kd≈ 100 nM) and at least another δ with about 20-fold lower affinity. The δ-containing CF 1, revealed only the low-affinity site(s) for δ. This was compatible with a 1:1 stoichiometry of δ in isolated CF 1. |
| Databáze: |
Supplemental Index |
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