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Convenient Synthesis of Multifunctional EDTA‐Based Chiral Metal Chelates Substituted with an S ‐Mesylcysteine
Author(s) -
Leonov Andrei,
Voigt Brigitte,
RodriguezCastañeda Fernando,
Sakhaii Peyman,
Griesinger Christian
Publication year - 2005
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200400907
Subject(s) - ethylenediaminetetraacetic acid , lanthanide , chemistry , moiety , chelation , luminescence , ligand (biochemistry) , metal ions in aqueous solution , divalent , paramagnetism , metal , cysteine , inorganic chemistry , biomolecule , ion , crystallography , stereochemistry , organic chemistry , materials science , biochemistry , optoelectronics , quantum mechanics , enzyme , receptor , physics
We describe the synthetic route to ethylenediaminetetraacetic acid (EDTA) derivatives that can be attached to surface‐exposed thiol functional groups of cysteine residues in proteins, via a methylthiosulfonate moiety that is connected in a stereochemically unique way to the C‐1 carbon atom of EDTA. Such compounds can be used to align proteins in solution without the need to add liquid crystalline media, and are, therefore, of great interest for the NMR spectroscopic analysis of biomolecules. The binding constant for the paramagnetic tag to lanthanide ions was determined by measuring luminescence. For the Tb +3 –ligand complex, a K b value of 6.5×10 17 M −1 was obtained. This value is in excellent agreement with literature values for the related EDTA compound. In addition, it could be shown that there is no significant reduction in the luminescence intensity upon addition of a 10 4 excess of Ca 2+ ions, indicating that this paramagnetic tag is compatible with buffers containing high concentrations of divalent alkaline earth ions.