Installation of a Rigid EDTA-Like Motif into a Protein α-Helix for Paramagnetic NMR Spectroscopy with Cobalt(II) Ions.

ABSTRACT

Coupling two copies of an iminodiacetic acid-cysteine hybrid ligand to a pair of cysteine residues positioned in an i, i+4 arrangement within a protein α-helix leads to generation of an EDTA-like metal ion-binding motif. Rigid binding of a Co(II) ion by this motif produces pseudo-contact shifts suitable for paramagnetic NMR structural studies.