Electron density of MerA
Last update on the 7th of October, 2019Here I study electron density of mercuric reductase (MerA) of Pseudomonas aeruginosa based on 1ZK7 PDB entry at resolution of 1.6 Å.
Electron density around the backbone
The electron density around the backbone was investigated at 3 significance levels: 1σ, 2σ, 3σ.
The following template command was used to produce electron density surfaces at different significance levels:
isomesh surface_name, 1zk7_map, sigma, backbone, 2.5, carve=2
. See fig. 1.
![](surface_grid.png)
Inner parts of protein have an electron density of very good quality whereas the start (left part) and end (right part) have electron density of lower significance. The "free" region of protein in the centre of images is also of lower significance. However, the structure seems to be fitted good into the electron density map.
![](surfaces_change.gif)
The inspection of one of inner alpha-helices has strengthen the conclusion about the quality of structure evaluation (fig. 2).
![](helix.png)
Electron density around residues
I selected 3 residues to investigate electron density around them (fig. 3).
![](residues.png)
Residues seem to be placed in space at the great agreement with electron density map.
Conclusion
The inferred structure seems to reflect electron density decently.