Fifteen years of the Protein Crystallography Station: the coming of age of macromolecular neutron crystallography

Chen, J.C.-H.; Unkefer, C.J.

doi:10.1107/S205225251601664X

Figure 2
Nuclear density map showing protonation of His57 in trypsin. Left, difference density map showing protonation of N^δ of His57. Center, 2F_o − F_c nuclear density map with double protonation of His57 and negative density peaks for the unexchanged H atoms. Right, difference density map with the proton modeled on Asp102. The contour shows that the proton belongs on His57 (solid lines) and not Asp102 (dotted lines). Reprinted with permission from Kossiakoff & Spencer (1981