Journal of Biomolecular NMR

, Volume 58, Issue 2, pp 123–128

The IR-15N-HSQC-AP experiment: a new tool for NMR spectroscopy of paramagnetic molecules

  • Simone Ciofi-Baffoni
  • Angelo Gallo
  • Riccardo Muzzioli
  • Mario Piccioli
Article

DOI: 10.1007/s10858-013-9810-2

Cite this article as:
Ciofi-Baffoni, S., Gallo, A., Muzzioli, R. et al. J Biomol NMR (2014) 58: 123. doi:10.1007/s10858-013-9810-2

Abstract

A crucial factor for the understanding of structure-function relationships in metalloproteins is the identification of NMR signals from residues surrounding the metal cofactor. When the latter is paramagnetic, the NMR information in the proximity of the metal center may be scarce, because fast nuclear relaxation quenches signal intensity and coherence transfer efficiency. To identify residues at a short distance from a paramagnetic center, we developed a modified version of the 15N-HSQC experiment where (1) an inversion recovery filter is added prior to HSQC, (2) the INEPT period has been optimized according to fast relaxation of interested spins, (3) the inverse INEPT has been eliminated and signals acquired as antiphase doublets. The experiment has been successfully tested on a human [Fe2S2] protein which is involved in the biogenesis of iron-sulfur proteins. Thirteen HN resonances, unobserved with conventional HSQC experiments, could be identified. The structural arrangement of the protein scaffold in the proximity of the Fe/S cluster is fundamental to comprehend the molecular processes responsible for the transfer of Fe/S groups in the iron-sulfur protein assembly machineries.

Keywords

Iron-sulfur proteins Paramagnetic NMR 15N-HSQC Pulse sequences Paramagnetic relaxation Anamorsin 

Copyright information

© Springer Science+Business Media Dordrecht 2014

Authors and Affiliations

  • Simone Ciofi-Baffoni
    • 1
  • Angelo Gallo
    • 1
  • Riccardo Muzzioli
    • 1
  • Mario Piccioli
    • 1
  1. 1.Magnetic Resonance Center and Department of ChemistryUniversity of FlorenceSesto FiorentinoItaly

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