Chiral Recognition between Dissymmetric Tb- and Eu(pyridine-2,6-dicarboxylate)33- Complexes and Fe(III) Proteins in Aqueous Solution. Luminescence Quenching by Cytochrome c from Horse Heart and Cytochrome c-550 from Thiobacillus versutus and Its Lys14 → Glu and Lys99 → Glu Mutants
| Autor: | and Gerard W. Canters, Stefan C.J. Meskers, Marcellus Ubbink, Harry P.J.M. Dekkers |
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| Rok vydání: | 1996 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry. 100:17957-17969 |
| ISSN: | 1541-5740 0022-3654 |
| DOI: | 10.1021/jp961381z |
| Popis: | The enantioselective quenching of the luminescence of racemic Ln(DPA)33- (Ln = Tb, Eu; DPA = 2,6-pyridinedicarboxylate) by ferricytochrome c proteins in aqueous solution has been studied by time-resolved luminescence and circular-polarization-of-luminescence spectroscopy. All title proteins appear to be very efficient quenchers with quenching rate constants on the order of 107−109 M-1 s-1 depending on the nature of the protein and Ln, on the absolute configuration of the Ln complex (Δ or Λ), and on the solution's ionic strength I. The ratio of the individual diastereomeric quenching rate constants, kqΔ/kqΛ, ranges from 1.2 up to 3 depending on the nature of the protein and Ln ion, but hardly on I. The average quenching rate, kqav (=(kqΔ + kqΛ)/2), also depends on the ground state lanthanide concentration, which allows for an estimate of the binding constant of ground state Ln complex to the active site of the protein: 7 × 102 (cytc) and 4 × 102 M-1 (cytc-550) at I = 0.022 M. The quenching process is mode... |
| Databáze: | OpenAIRE |
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