Journal of Biomolecular NMR

, Volume 21, Issue 3, pp 249–261

Amide proton temperature coefficients as hydrogen bond indicators in proteins

  • Tomasz Cierpicki
  • Jacek Otlewski
Article

DOI: 10.1023/A:1012911329730

Cite this article as:
Cierpicki, T. & Otlewski, J. J Biomol NMR (2001) 21: 249. doi:10.1023/A:1012911329730

Abstract

Correlations between amide proton temperature coefficients (ΔσHN/ΔT) and hydrogen bonds were investigated for a data set of 793 amides derived from 14 proteins. For amide protons showing temperature gradients more positive than −4.6 ppb/K there is a hydrogen bond predictivity value exceeding 85%. It increases to over 93% for amides within the range between −4 and −1 ppb/K. Detailed analysis shows an inverse proportionality between amide proton temperature coefficients and hydrogen bond lengths. Furthermore, for hydrogen bonds of similar bond lengths, values of temperature gradients in α-helices are on average 1 ppb/K more negative than in β-sheets. In consequence, a number of amide protons in α-helices involved in hydrogen bonds shorter than 2 Å show ΔσHN/ΔT < −4.6 ppb/K. Due to longer hydrogen bonds, 90% of amides in 310 helices and 98% in β-turns have temperature coefficients more positive than –4.6ppb/K. Ring current effect also significantly influences temperature coefficients of amide protons. In seven out of eight cases non-hydrogen bonded amides strongly deshielded by neighboring aromatic rings show temperature coefficients more positive than −2 ppb/K. In general, amide proton temperature gradients do not change with pH unless they correspond to conformational changes. Three examples of pH dependent equilibrium showing hydrogen bond formation at higher pH were found. In conclusion, amide proton temperature coefficients offer an attractive and simple way to confirm existence of hydrogen bonds in NMR determined structures.

amide proton temperature coefficients chemical shifts hydrogen bonds ring current secondary structures 

Copyright information

© Kluwer Academic Publishers 2001

Authors and Affiliations

  • Tomasz Cierpicki
    • 1
  • Jacek Otlewski
    • 1
  1. 1.Laboratory of Protein Engineering, Institute of Biochemistry and Molecular BiologyUniversity of WrocławPoland

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