Hi, as I understand your question, you're asking whether the EM density
values in a cryo-EM map ('MRC' format) would be expected to be comparable
with the corresponding electron density values in a CCP4 XRD map obtained
by FT of the map coefficients from an MTZ X-ray reflexion file at the same
nominal resolution, if all else is equal. Of course that's a very big 'if'
because the observed densities will depend on a whole host of factors, such
as the atomic displacement parameters, which are unlikely to be equal under
all circumstances.
Assuming for the sake of argument that all else is equal, the densities
would still not be expected to be equal for the simple reason that X-ray
scattering factors (FT of atomic electron density) are obviously not the
same as electron scattering factors and also have a different energy
dependency.
Hope this helps.
-- Ian
On 3 May 2015 at 12:15, Smith Liu <[email protected]> wrote:
> If for both a mtz density and mrc map I set the contour level as 0.15,
> does the 015 has the comparable significance for the mtz density and mrc
> map?
>
> Smith
>
>
>
