Figure 2 - full size

Figure 2. Fig. 2. Electrondensityfor a guanidinium133intheribonucleasestruc- ture is shown.The 2F,, ~ F, mapwascontouredatthestandarddeviation ofthemap,andthemodel used togeneratethephasescontained no ua- nidinium. he distancebetweentheoxygenof Tyr 76andtheguanidinium nitrogen is only 2.5 A. Te distancebetweentheclosestnitrogensinGua 133 andGua132 s 3.3 A. The peptidebond of residue 62, whch is shown below Gua 133 inthisfigure, is further away. Thedistancesfor all ofthe proteininteractions with Gua 133areshon in Figure A.

The above figure is reprinted by permission from the Protein Society: Protein Sci (1997, 6, 1727-1733) copyright 1997.