Identification of histidine tautomers in proteins by 2D 1H/13C(delta2) one-bond correlated NMR.

@article{Sudmeier2003IdentificationOH,
  title={Identification of histidine tautomers in proteins by 2D 1H/13C(delta2) one-bond correlated NMR.},
  author={James L. Sudmeier and Elizabeth M Bradshaw and Kristin E Coffman Haddad and Regina M Day and Craig J. Thalhauser and Peter A. Bullock and William W. Bachovchin},
  journal={Journal of the American Chemical Society},
  year={2003},
  volume={125 28},
  pages={8430-1}
}
If the 13Cdelta2 chemical shift of neutral ("high pH") histidine is >122 ppm, primarily Ndelta1-H tautomer (2) is indicated; if it is <122 ppm, primarily Nepsilon2-H tautomer (1) is indicated. His resonances from the catalytic triad of active serine proteases, for example, are readily distinguished from those of denatured enzyme. The 13Cdelta2 chemical shifts increased by 6.2 ppm for the catalytic histidines in both alpha-lytic protease and subtilisin BPN' in raising the pH from that of… CONTINUE READING