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![[Figure 3]](gm5052fig3mag.jpg)
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Figure 3
Bromine phasing experiments with 3,5-dibromosalicilic acid using STD and HS scans. (a) Snapshot of the crystal with the position 1 of the STD and traces of the HS scans between position 2 and 3 and between position 4 and 5. (b) Chemical structure of 3,5-dibromosalicilic acid showing the weak bond (dotted grey) between the bromine atoms (brown), the phenyl ring to which they are covalently bound. These bonds are susceptible to X-rays. (c, d) Plots of σano and CC1/2, respectively, showing better statistics for the HS scans. (e, f) Contrast versus cycle plots from SHELXE phasing (Sheldrick, 2002  ) displayed in HKL2MAP (Pape & Schneider, 2004) for the STD data (left) and the HS data (right), showing successful phasing for the HS data but failing for the STD data. (g–h) Untraced phased maps contoured at 1.5 standard deviations for STD (g) and HS (h). Only the HS map is easily traceable (model placed into electron density manually). The separation between the identified bromine atoms in the STD data is correct. However, using these atoms, to superimpose the TTR model into the density, shows the inferior quality of the STD data phasing with numerous breaks in the β strands and false connections. |
![[Figure 3]](gm5052fig3.jpg)
 | JOURNAL OF SYNCHROTRON RADIATION |
ISSN: 1600-5775
