In fact, if you want the truth, what I now do is to download the sf.cif file, use ccp4i to regenerate the MTZ (with the same Free R-factor flags that the authors have used for structure refinement). Then feed that into Phenix for a few rounds of positional and temperature factor refinement with TLS (very few, I am not really re-refining the structure) and look at the resulting e.d. maps. If the structure is "old" then I get improved model statistics and (I assume) improved electron density maps.
Fred.
> Message du 12/12/09 00:33
> De : "Eric Bennett"
> A : [log in to unmask]
> Copie à :
> Objet : Re: [ccp4bb] FW: pdb-l: Retraction of 12 Structures....
>
>
> Fred V wrote:
>
> >I personally like to visualise the electron density as well,
> >however, I do think that a non-crystallographer will go through the
> >trouble of downloading the structure factors, installing ccp4/coot
> >etc.
> >
> >Fred.
>
> They shouldn't have to go through some of that trouble. Maps should
> be deposited.
>
> Even if you have good crystallography knowledge can you exactly
> reproduce the map the authors were looking at? Software algorithms
> change over the years... the software version the authors used might
> not even be compilable on modern systems... some authors may not
> fully specify all software settings required to get the same map
> (perhaps they used NCS but you have to re-determine the NCS
> yourself)... etc.
>
>
>
>
> --
> Eric Bennett, [log in to unmask]
>
>
|