(Strept)avidin as host for biotinylated coordination complexes: stability, chiral discrimination, and cooperativity

Loosli, Andreas; Rusbandi, Untung Edy; Gradinaru, Julieta; Bernauer, Klaus; Schläpfer, Carl-Wilhelm; Meyer, Michel; Mazurek, Sylwester; Novic, Marjana; Ward, Thomas R.

doi:10.1021/ic051405t

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Journal article

(Strept)avidin as host for biotinylated coordination complexes: stability, chiral discrimination, and cooperativity

Loosli, Andreas Institute of Chemistry, University of Neuchâtel, Switzerland
Rusbandi, Untung Edy Institute of Chemistry, University of Neuchâtel, Switzerland
Gradinaru, Julieta Institute of Chemistry, University of Neuchâtel, Switzerland
Bernauer, Klaus Institute of Chemistry, University of Neuchâtel, Switzerland
Schläpfer, Carl-Wilhelm Institute of Inorganic Chemistry, University of Fribourg, Switzerland
Meyer, Michel Laboratoire d'Ingénierie Moléculaire pour la Séparation et les Applications des Gaz, Université de Bourgogne, Faculté des Sciences, France
Mazurek, Sylwester Institute of Chemistry, University of Neuchâtel, Switzerland - Laboratory of Chemometrics, National Institute of Chemistry, Ljubljana, Slovenia
Novic, Marjana Laboratory of Chemometrics, National Institute of Chemistry, Ljubljana, Slovenia
Ward, Thomas R. Institute of Chemistry, University of Neuchâtel, Switzerland

24.12.2005

Published in:

Inorganic Chemistry. - 2006, vol. 45, no. 2, p. 660-668

English Incorporation of a biotinylated ruthenium tris(bipyridine) [Ru(bpy)₂(Biot-bpy)]²⁺ (1) in either avidin or streptavidin-(strept)avidin-can be conveniently followed by circular dichroism spectroscopy. To determine the stepwise association constants, cooperativity, and chiral discrimination properties, diastereopure (Λ and δ)-1 species were synthesized and incorporated in tetrameric (strept)avidin to afford (δ-[Ru(bpy)₂(Biot-bpy)]²⁺)_x⊂avidin, (Λ- [Ru(bpy)₂(Biot-bpy)]²⁺)_x⊂avidin, (δ-[Ru(bpy)₂(Biot- bpy)]²⁺)_x⊂streptavidin, and (Λ-[Ru(bpy)₂(Biot-bpy)]²⁺) _x⊂streptavidin (x = 1-4) For these four systems, the overall stability constants are log β₄ = 28.6, 30.3, 36.2, and 36.4, respectively. Critical analysis of the CD titrations data suggests a strong cooperativity between the first and the second binding event (x = 1, 2) and a pronounced difference in affinity between avidin and streptavidin for the dicationic guest 1 as well as modest enantiodiscrimination properties with avidin as host.

Faculty

Faculté des sciences et de médecine

Department

Département de Chimie

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