Roberto,

The reviewer's request is complete nonsense. The problem is how to best and politely respond so as not to prevent the paper from being accepted. Best would be to have educated editors who could simply tell you to ignore that request.

Since this issue comes up quite often still, I think we all should come up with a canned response to such a request.

One way to approach this issue is to avoid saying something like "the structure has been refined to 2.2Å resolution", but instead say "has been refined using data to a resolution of 2.2Å.", or even ""has been refined using data with an I/sigmaI > 1.5 (or whatever)". Next could be to point out that even data with an I/sigmaI of 1 can contain information (I actually don't have a good reference for this, but I'm sure someone else can provide one'), and inclusion of such data can improve refinement stability and speed of convergence (not really important in a scientific sense, though).

The point is that all of your data combined result in a structure with a certain resolution, pretty much no matter what high-resolution limits you choose (I/sigmaI of 0.5, 1.0, or 1.5). As long as you don't portrait your structure of having a resolution corresponding to the resolution of the high-resolution limit of your data, you should be fine.

Now, requesting to toss out data with I/sigmaI of <3 simply reduces the resolution of your structure. You could calculate two electron density maps and show that your structure does indeed improve when including data with /sigmaI of <3. One criterion could be to use the optical resolution of the structure.

Hope that helps.

Best,
MM

On Mar 3, 2011, at 6:29 AM, Roberto Battistutta wrote:

> Dear all,
> I got a reviewer comment that indicate the "need to refine the structures at an appropriate resolution (I/sigmaI of >3.0), and re-submit the revised coordinate files to the PDB for validation.". In the manuscript I present some crystal structures determined by molecular replacement using the same protein in a different space group as search model. Does anyone know the origin or the theoretical basis of this "I/sigmaI >3.0" rule for an appropriate resolution?
> Thanks,
> Bye,
> Roberto.
> 
> 
> Roberto Battistutta
> Associate Professor
> Department of Chemistry
> University of Padua
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