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Figure 3
Quality of the calculated electron density from diffraction data sets of in vivo grown TbCatB crystals collected using serial synchrotron crystallography (3.0 Å resolution; left) and SFX (refined at 3.0 Å resolution; PDB entry 4hwy ; right) techniques. (a, b) Surface representation of the TbCatB–propeptide complexes independently solved by molecular replacement using the mature TbCatB structure (Koopmann et al., 2012BB21) as a search model. The solutions consistently revealed additional electron density (2Fobs − Fcalc, 1σ, blue) of the propeptide (green) that is bound to the V-shaped substrate-binding cleft and of two carbohydrate structures (yellow) N-linked to the propeptide (c, d) and to the mature enzyme (e, f). Considering the difference in maximum resolution, the propeptide, as well as both carbohydrates, are well defined within the electron-density maps, confirming that the phases are not biased by the search model.

IUCrJ
Volume 1| Part 2| February 2014| Pages 87-94
ISSN: 2052-2525
doi:10.1107/S2052252513033939