The use of noncrystallographic symmetry averaging to solve structures from data affected by perfect hemihedral twinning

Sabin, C.; Plevka, P.

doi:10.1107/S2053230X16000923

Figure 3
Comparison of (2|F_obs^detwinned| − |F_calc|), φ_calc electron-density maps at various stages of AiV1 structure determination. (a) Electron-density map calculated using the phases and twinning portions derived from the BEV model converted to a polyalanine chain. The BEV model converted to polyalanine is shown in stick representation with the C atoms coloured green. (b) Electron-density map calculated using the phases and twinning portions from the BEV model converted to polyalanine and refined by ten cycles of NCS averaging using the BEV-derived mask. The BEV model converted to polyalanine is shown in stick representation with the C atoms coloured green. (c) Electron-density map calculated using the phases and twinning portions from the BEV model converted to polyalanine and refined by 30 cycles of NCS averaging using the correlation map-derived mask. See §

3.6 for details of the mask preparation. The BEV model converted to polyalanine is shown in stick representation with the C atoms coloured green. (d) The same electron-density map as in (c) with the final AiV1 model shown in stick representation with the C atoms coloured red. (e) An electron-density map calculated using the phases and the twinning portions derived from the final AiV1 model. The final AiV1 model is shown in stick representation with the C atoms coloured red. (f) Electron-density map calculated using the phases and twinning portions derived from the final AiV1 structure and refined by ten cycles of NCS averaging. The final AiV1 model is shown in stick representation with the C atoms coloured red. (g) Electron-density map calculated using the phases and twinning portions derived from the φCb5 structure. The model of φCb5 is shown in stick representation with the C atoms coloured green. (h) Electron-density map calculated using the phases and twinning portions from the φCb5 structure and refined by ten cycles of NCS averaging. The model of φCb5 is shown in stick representation with the C atoms coloured green.

STRUCTURAL BIOLOGY
COMMUNICATIONS

ISSN: 2053-230X

Volume 72| Part 3| March 2016| Pages 188-197

doi:10.1107/S2053230X16000923

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