Figure 2: Minor conformations are obscured in conventional maps but are revealed by background correction. | Nature Communications

Figure 2: Minor conformations are obscured in conventional maps but are revealed by background correction.

From: A multi-crystal method for extracting obscured crystallographic states from conventionally uninterpretable electron density

Figure 2

1D simulations are used to illustrate 3D electron density. (a) The actual crystal contains 80% major (black) and 20% minor (orange) states, which are largely dissimilar (correlation: 0.42). (b) Conventional (2mFo–DFc) maps (blue) show only the superposition, which resembles the major far more than the interesting minor state (correlations: 0.98 and 0.59; in practice, the scale is arbitrary). Isomorphous difference (Fo–Fo) maps (green) show the subtraction of the full-occupancy major state from the observed data set, and do not resemble the minor state either, except where the major state has low density (right side). (c) ‘Event maps’ (scaled for comparison), generated as in equation (1) for different values of BDC, reveal the minor state optimally for only one value of BDC (0.8, indicated in red). BDC=0.0 corresponds to the observed density, and BDC=1.0 to a Fo–Fo map.

Back to article page