-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Dear Bernhard,
without ever having looked at an NMR experiment, intuitively the
resolution of an NMR experiment should be given as the magnitude of the
minimal chemical shift that could be observed/distinguished. Beware that
'resolution' does not necessarily mean 'optical resolution', and the
fact that we provide the resolution of diffraction experiments in
Angstrom can surely be confusing, as well. 1/Angstrom, as often cited in
charge density studies, much better reflects that 'resolution' of a data
set refers to the scattering angle at which there were still spots on
the detector.
Concerning your quote: even scientists are not free of emotions even
though sometimes one might get the impression that some pretend they
were, which inevitably leads to tensions that might be released in
phrases like your quote...
Cheers,
Tim
On 01/12/2012 10:30 AM, Bernhard Rupp (Hofkristallrat a.D.) wrote:
> Dear All,
>
> I read an interesting statement in an NMR review:
>
> ".... regions of a protein or
> DNA ⁄ RNA molecule that are flexible in the crystal do
> not provide coherent X-ray scattering and hence do
> not contribute to the final electron density map. Thus,
> for all intents and purposes, they can effectively be
> ignored."
>
> Besides that I was not aware that disorder across molecules implies incoherence
> in scattering, I think this is quite some strong tobacco coming from what is
> primarily a crystallization screening tool ;-)
>
> Cheers, BR
>
> PS: I am grappling with the meaning of resolution in NMR. I can see that it
> could be related to comparable data/parameter ratios, although I am even
> less clear about the weights of NMR restraint weights than in the case of MX...
> some cross-trained person out there who can explain?
>
- --
- --
Dr Tim Gruene
Institut fuer anorganische Chemie
Tammannstr. 4
D-37077 Goettingen
GPG Key ID = A46BEE1A
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.10 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
iD8DBQFPDrboUxlJ7aRr7hoRAqGJAKCRq3y9yeSLiy+e3P3Se9XqDVBLwQCeM921
vt5ADacDA81CNw0us7k+gL8=
=VN3V
-----END PGP SIGNATURE-----
|