 | Acta Crystallographica Section D Acta Crystallographica Section D BIOLOGICAL CRYSTALLOGRAPHY |
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![[Figure 2]](dz5158fig2mag.jpg)
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Figure 2
Analysis of a 1° rotation photograph from the 2qyv data set. Twofold pseudotranslational symmetry produces a main lattice of bright reflections (yellow boxes) and a coset of weak reflections (magenta boxes) that is identified incorrectly and correctly in (a) and (c), respectively. The correct cell-doubling transformation can be selected by measuring the intensities I at predicted coset spot positions, but a potential pitfall of this calculation is illustrated by the single outlier that heavily biases the average intensity 〈I〉 in (a). The difficulties are resolved by modeling the entire population as either a Gaussian distribution indicative of measurement noise (b) or an approximate exponential distribution indicative of real Bragg diffraction (d). Red dots in (b) and (d) are intensity observations from the cosets depicted in (a) and (c) respectively, in the 8–3 Å resolution range, plotted against sequence number k, where the set of intensities has been re-sorted by increasing value. Blue curves show the best-fit expected intensities, after outlier rejection, for Gaussian or exponential distributions as in (8) ![[link]](../../../../../../logos/arrows/d_arr.gif) and (11). |
![[Figure 2]](dz5158fig2.jpg)
| BIOLOGICAL CRYSTALLOGRAPHY |
ISSN: 1399-0047
