Dear All, Electron density picture is attached here.
or https://docs.google.com/leaf?id=0B89uj7DSbtUWNDRmMzZhNTAtMzlkMC00MDllLTgxYmItNDI0NzUwMjdlNTli&hl=en I am working on a structure at 1.45 Ang resolution. I have noticed a density that looks like water. However, it is surrounded by by six other atoms in the hexa-coordinate geometry. In addition to three coordinating waters (2.15 Ang, 2.7 ang, 2.85 Ang), side chain carbonyl oxygen atoms of an asparagine (2.5 Ang) and a glutamine (2.25 ang) and a methionine sulfur is at 3.07 Ang from this central atom. Based on this geometry we assume it is a sodium ion. This atom seems to have an occupancy of 0.8 and all the surrounding atoms are fully occupied. Do you think it is a sodium or a water molecule? I would like your help to understand if a sulfur....sodium interaction is possible. If there are some examples can you kindly suggest me? Thank you Chandan
