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Chlortetracycline as a fluorescent probe of the first nucleotide binding site of the coupling factor CF 1 of spinach chloroplasts
Author(s) -
Girault G.,
Galmiche J.M.
Publication year - 1978
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(78)80068-4
Subject(s) - nucleotide , coupling (piping) , spinach , physics , fluorescence , chemistry , stereochemistry , materials science , optics , biochemistry , gene , metallurgy
Tetracyclines bind divalent cations such as MgZC or Cap forming highly fluorescent complexes [ 11. Tetracyclines similarly bind to macromolecules such as ribosomes [2] bovine serum albumin [3] or to membranes [ 1,4] with a concomitant enhancement of their fluorescence. It is generally thought that tetracyclines bind to macromolecules and membranes by the intermediate action of divalent cations [2] but other mechanisms such as absorption, ionic and hydrophobic binding have also been proposed [S ] . Although the binding of tetracycline to membranes is defmitely facilitated by divalent cations [6] its binding to protein, e.g., serum albumin, might be mediated by a hydrophobic mechanism [ 1,5] . The increase of fluorescence which occurred when chlortetracycline was bound to the yeast mitochondrial ATPase complex was reported quenched by addition of ATP or ADP [ 71. Possible explanations for these changes are: 1. ADP or ATP might change the polarity of the site where chlortetracycline binds Mg” or more likely competes with chlortetracycline for binding to the cationic sites of the ATPase. Such a competitive effect has been proposed [6] to explain why addition of ATP or ADP inhibits the uptake of tetracycline by membrane preparations of Escherichiu coli. 2. ADP or ATP could change the hydrophobicity of