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> at the resolution you're working at the RMSD on bond 
> lengths should be ca. 0.012, not 0.02 A.

Interesting statement. I agree that for 
very well determined small molecule structures, the
overall bond length variation is about 0.014 A or so.

That fits quite well with what you say. It just means 
that the structure should be restrained to reflect
reality.

But: What does coordinate rmsd exactly have to do with 
resolution? If the 3.5 A structure has 0.012 A
rmsd, does that mean that a 1.2 A structure
should have 0.005? I have a feeling that would
be a serious case of over-restraining.

Should not all structures reflect the same 
'real world' rmsd (plus minus some minor individuality) 
if the restraint weights are properly selected?

Maybe the small molecule/shelxl fellows may chime in here:
What is the expected rmsd for a high res protein 
structure vs. a low res? I had a feeling that
super low rmsd is partly abused as a sign of crystallographic
prowess, like building fantasy stuff into nonexistent density
just to have no missing residues &c &c &c... 

Thx, br


 

 


 


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