3‐Mercapto‐2,6‐Pyridinedicarboxylic Acid: A Small Lanthanide‐Binding Tag for Protein Studies by NMR Spectroscopy |
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| Authors: | Bradley Man Xun‐Cheng Su Dr Haobo Liang Dr Shane Simonsen Dr Thomas Huber Dr Barbara?A Messerle Prof Gottfried Otting Prof |
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| Institution: | 1. School of Chemistry, University of New South Wales, Sydney NSW 2052 (Australia);2. Research School of Chemistry, Australian National University, Canberra ACT 0200 (Australia), Fax: (+61)?2‐61250750;3. School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane QLD 4072 (Australia) |
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| Abstract: | Paramagnetic effects from lanthanide ions present powerful tools for protein studies by nuclear magnetic resonance (NMR) spectroscopy provided that the lanthanide can be site‐specifically and rigidly attached to the protein. A new, particularly small and rigid lanthanide‐binding tag, 3‐mercapto‐2,6‐pyridinedicarboxylic acid (3MDPA), was synthesized and attached to two different proteins via a disulfide bond. The complexes of the N‐terminal domain of the E. coli arginine repressor (ArgN) with seven different paramagnetic lanthanide ions and Co2+ were analyzed in detail by NMR spectroscopy. The magnetic susceptibility anisotropy (Δχ) tensors and metal position were determined from pseudocontact shifts. The 3MDPA tag generated very different Δχ tensor orientations compared to the previously studied 4‐mercaptomethyl‐DPA tag, making it a highly complementary and useful tool for protein NMR studies. |
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| Keywords: | lanthanides magnetic properties NMR spectroscopy protein labeling pseudocontact shifts |
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