Site-specific tagging proteins with a rigid, small and stable transition metal chelator, 8-hydroxyquinoline, for paramagnetic NMR analysis.
 

Site-specific tagging proteins with a rigid, small and stable transition metal chelator, 8-hydroxyquinoline, for paramagnetic NMR analysis.

Related Articles Site-specific tagging proteins with a rigid, small and stable transition metal chelator, 8-hydroxyquinoline, for paramagnetic NMR analysis.

J Biomol NMR. 2016 Jan 6;

Authors: Yang Y, Huang F, Huber T, Su XC

Abstract
Design of a paramagnetic metal binding motif in a protein is a valuable way for understanding the function, dynamics and interactions of a protein by paramagnetic NMR spectroscopy. Several strategies have been proposed to site-specifically tag proteins with paramagnetic lanthanide ions. Here we report a simple approach of engineering a transition metal binding motif via site-specific labelling of a protein with 2-vinyl-8-hydroxyquinoline (2V-8HQ). The protein-2V-8HQ adduct forms a stable complex with transition metal ions, Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). The paramagnetic effects generated by these transition metal ions were evaluated by NMR spectroscopy. We show that 2V-8HQ is a rigid and stable transition metal binding tag. The coordination of the metal ion can be assisted by protein sidechains. More importantly, tunable paramagnetic tensors are simply obtained in an ?-helix that possesses solvent exposed residues in positions i and i*+*3, where i is the residue to be mutated to cysteine, i*+*3 is Gln or Glu or i*-*4 is His. The coordination of a sidechain carboxylate/amide or imidazole to cobalt(II) results in different structural geometries, leading to different paramagnetic tensors as shown by experimental data.


PMID: 26732873 [PubMed - as supplied by publisher]



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