Figure 2
![Figure 2](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1472-6807-8-41/MediaObjects/12900_2008_Article_206_Fig2_HTML.jpg)
Examples of the poor fits of the hydrogen positions to the 2F 0 -F c electron-density map (at 0.5σ contour level) in high-resolution X-ray structures. These conformations are refinement artifacts (A) Thr-A41 [1C75] at χ2 = -120°, (B) Thr-A104 [1JM1] at χ2 = 0°; and (C) Tyr-A3 [1RW1] at χ3 = 60°.