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Improved measurement of (15)N-[(1)H] NOEs in the presence of H(N)-water proton chemical exchange. | LitMetric

Improved measurement of (15)N-[(1)H] NOEs in the presence of H(N)-water proton chemical exchange.

J Magn Reson

Department of Biochemistry, Molecular Biology, & Biophysics, University of Minnesota Health Sciences Center, 6-155 Jackson Hall, 321 Church Street, Minneapolis, MN 55455, USA.

Published: November 2001

AI Article Synopsis

  • A novel method is introduced to accurately measure (15)N-[(1)H] NOEs in biomolecules while accounting for H(N)-water proton chemical exchange.
  • The technique requires three specific measurements: one with nonselective proton saturation and two under varying water saturation conditions to ascertain the (15)N signal's equilibrium value.
  • Results from studies on two peptides show that traditional methods using short recycle times may produce incorrect NOE values, especially when chemical exchange is rapid, suggesting the new method offers improved accuracy.

Article Abstract

A simple method is presented to accurately determine (15)N-[(1)H] NOEs in biomolecules in the presence of H(N)-water proton chemical exchange. Three measurements are required: one with nonselective proton saturation and two with different water saturation conditions to determine the equilibrium value of the (15)N signal. This approach is exemplified with data on two peptides, one helix-forming 17-mer and one compactly folded 56-mer. Results indicate that (15)N-[(1)H] NOEs determined using the standard approach with short recycle times (3 to 4 s) can be significantly in error when H(N)-water proton chemical exchange is relatively rapid, water proton relaxation is relatively slow, and (15)N-[(1)H] NOEs are away from the value of -1. This new method avoids such inaccuracies resulting from the use of short recycle times.

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Source
http://dx.doi.org/10.1006/jmre.2001.2412DOI Listing

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