I would try placing waters in the positive difference Fourier peaks
(waters could make hydrogen bonds, if you follow the standard colour
coding for the atoms), refine and see how the density looks like then.
Kadhirvel Saraboji wrote:
> Hi all,
>
> In one of my 1.6Ang resolution structure, I came across a strange
> density. I tried to model this with PEG but after refinement still
> peaks appear around PEG at ~1.45-1.7 Ang.
>
> The images before and after PEG insertion is at:
> http://mole.mbfys.lu.se/~saraboji/peg_density.jpg
> (Fo-Fc and 2Fo-Fc is at 3 and 1sigma)
>
> I feel this to be a PEG modification, which I could not resolve. My
> crystallization condition contains PEG, Sodium acetate, and Zinc
> chloride. Does anyone have experience in resolving such a density?
>
> Thanks in advance
>
> With best regards
> Saraboji
>
>
>
> ---------------------------------
> Dr. SARABOJI KADHIRVEL
> Post-Doctoral Researcher, Molecular Biophysics
> Center for Molecular Protein Science, Kemicentrum,
> Lund University, Box 124, SE-221 00 Lund, Sweden
> Tel: +46-46-2221448 (off); +46-76-2374172 (mob),
> Fax: +46-46-2224692; e-mail: [log in to unmask]
>
>
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