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![[Figure 1]](kw5130fig1mag.jpg)
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Figure 1
Noncrystallographic symmetries of the P31 crystals. (a) κ = 180° section of the self-rotation map calculated in MOLREP (Vagin & Teplyakov, 2010  ) using a 30 Å integration radius and Fo to 6 Å maximum resolution. There are two sets of κ = 180° peaks in the ab plane of the trigonal crystallographic lattice, one set at φ = −37.1° with 61% of the origin peak height and the other at φ = −59.4° with 50% of the origin peak height, indicating the presence of twofold axes that are approximately mutually perpendicular, hence the approximate 222 rotational symmetry. (b) Native Patterson map calculated to 6 Å maximum resolution. The peak at (2/3, 1/3, 0) with 33.8% of the origin peak height indicates threefold translational NCS (translational pseudo-symmetry) in the [−1, 1, 0] direction. The rotational and translational NCS in combination generate 12 NCS copies per asymmetric unit. (c) and (d) were calculated as (a) and (b) but using Fo after anisotropy correction. The peak positions are unaffected by this correction, but the peak heights of self-rotation in (c) have decreased to 54 and 46% of the origin, respectively, and the peak height of the native Patterson in (d) has decreased to 32.4% of the origin. (e) and (f) were calculated after the re-refinement, using Fc that describe the untwinned model. In (e), the two sets of κ = 180° peaks in the ab plane, at φ = −28.8° with 81% of the origin peak height and φ = −58.11° with 79% of the origin peak height, accounted for the 222 rotational NCS detected in (a). In (f), the native Patterson peak at (2/3, 1/3, 0) with 46.4% of the origin peak height accounted for the threefold translational NCS detected in (b). The peaks in (a)–(d) are broadened by twinning. |
![[Figure 1]](kw5130fig1.jpg)
 | STRUCTURAL BIOLOGY |
ISSN: 2059-7983
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