view article

Figure 7
Fourier difference density maps of the active site of XI calculated using FFT (Ten Eyck, 1973BB70) through the RIDL pipeline (Bury & Garman, 2018BB14). Here, each Fobs,nFobs,1 map has been calculated using the observed structure factor amplitudes |Fobs,n| and |Fobs,1| associated with data sets n and 1, respectively, using the calculated phase set corresponding to the 0.13 MGy low-dose refined coordinate model. The Fobs,nFobs,1 maps represent the electron density loss between the lowest-dose data set and each higher-dose data set n > 1. (a, b) Difference density maps for Fobs,2Fobs,1 contoured at ±3σ (0.07 e Å−3), (c, d) for Fobs,7Fobs,1 (negative/positive difference densities in red/green, respectively). The increase in damage with increasing dose, especially at the active site and the surroundings of the catalytic metals, is clear. The difference density maps also reflect visually how the electron density around the catalytic metal ion changes. The conformation with the highest occupancy, A, is used by RIDL but, as mentioned in the text, the RIDL analysis is not sensitive enough to detect the radiation damage associated with the small structural changes seen between A and B conformations.

Journal logoJOURNAL OF
ISSN: 1600-5775
Follow J. Synchrotron Rad.
Sign up for e-alerts
Follow J. Synchrotron Rad. on Twitter
Follow us on facebook
Sign up for RSS feeds