Use of protonated rather than neutral histidine, and proline-effect correction, enhances the accuracy of CheShift-computed 13C(alpha); chemical shifts.

MARTIN O.A.; VILA, J.A.; SCHERAGA H.A.

Córdoba

Workshop; I Workshop argentino de biofisicoquímica de proteínas; 2011

A server (CheShift) is available to predict the 13C(alpha) chemical shifts of protein structures fast and accurately. Analysis of 367 histidines from 97 X-ray-determined protein structures, for which there is also a complete set of observed 13C(alpha) chemical shifts obtained at pH’s between 3.5 to 7.6, indicates that CheShift 13C(alpha) chemical shifts, computed by using the protonated form for the imidazole ring of His, H+, rather than the neutral N(delta)1-H or N(epsilon)2-H tautomers, lead to better agreement with the observed values. In addition, the presence of 950 residues preceding proline in the protein set confirms the importance of considering the proline-effect correction on the CheShift computed 13C(alpha) chemical shifts. Consequently use of the protonated form of histidine and the proline-effect correction will enhance the accuracy of the predictions of the CheShift server.