6533b7dbfe1ef96bd1270b41
RESEARCH PRODUCT
(Strept)avidin as host for biotinylated coordination complexes: stability, chiral discrimination, and cooperativity
Thomas R. WardSylwester MazurekJulieta GradinaruCarl Wilhelm SchlaepferMarjana NovicUntung E. RusbandiMichel MeyerKlaus BernauerAndreas Looslisubject
StreptavidinCircular dichroismProtein ConformationStereochemistryBiotinchemistry.chemical_elementCooperativity010402 general chemistry01 natural sciencesInorganic ChemistryStructure-Activity RelationshipBipyridinechemistry.chemical_compound22'-DipyridylBacterial ProteinsBiotinCoordination ComplexesBiotinylation[CHIM.COOR]Chemical Sciences/Coordination chemistryPhysical and Theoretical ChemistryComputingMilieux_MISCELLANEOUSMolecular Structurebiology010405 organic chemistry[ CHIM.COOR ] Chemical Sciences/Coordination chemistryAvidinProtein Structure Tertiary0104 chemical sciencesRuthenium[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistryCrystallographychemistryBiotinylation[ CHIM.THEO ] Chemical Sciences/Theoretical and/or physical chemistrybiology.proteinStreptavidinAvidindescription
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.
year | journal | country | edition | language |
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2005-12-24 |