0000000000379505

AUTHOR

Thomas R. Ward

showing 2 related works from this author

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

2005

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…

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.proteinStreptavidinAvidin
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An Iron-Based Molecular Redox Switch as a Model for Iron Release from Enterobactin via the Salicylate Binding Mode

2001

The iron release mechanism from protonated ferric enterobactin [Fe(III)(enterobactinH(3))] via the salicylate binding mode was probed. For this purpose, a tripodal dodecadentate ligand incorporating three salicylamide (OO) and three bipyridine (NN) binding sites was synthesized as well as iron complexes thereof. It was shown that a ferric ion coordinates selectively to the hard salicylamides and a ferrous ion binds to the softer bipyridines. Upon reduction or oxidation, the iron translocates reversibly and intramolecularly from one site to the other, thus displaying switchlike properties. Both states were characterized by cyclic voltammetry and visible and Mössbauer spectroscopy. The Mössba…

ChemistryLigandInorganic chemistryProtonationRedoxFerrousInorganic ChemistryBipyridinechemistry.chemical_compoundEnterobactinPolymer chemistrymedicineFerricPhysical and Theoretical ChemistryCyclic voltammetrymedicine.drugInorganic Chemistry
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