Hi Pavel,

I am very lucky to see 2 maps of the same protein, at roughly the same resolution, one by Xray and the other by EM (it's not that common). The details from the 2 maps are however different...

Here is my procedure, please let me know what you think:
- convert .mrc map to .mtz ; I get F, PHIF.
- supperpose the maps:
map1: labels 2FOFCWT, PH2FOFCWT
map2: F, PHIF.
I also provided the 2 PDBs as it is clearly stated on the input files definitions.

It worked, with the 2 maps superposed that I can look and compare.

However, for some reason, the superposition has been done on chain C and D of the crystallograhic model instead of chain AB (4 chains in the asymmetric unit, making 2 dimers). Is there a reason there, choosing the closest structure, best fit? (I see that it is possible to define a superposition)
Another thing is that it creates a "supperposition in the middle", meaning neither on model1 nor model2 from the input, and not a crystallographic symmetric of model1. So I can't use the full crystallographic maps, I have a "simplified" version of it.
 
Please let me know if I'm doing something wrong as haven't yet invested into understanding map formats.
Thanks
Vincent

ps: Zhijie, thanks for the Chimera tip. I'll have a look into it later.



On 04/10/2018 12:00, Pavel Afonine wrote:
Hi Vincent,

I am trying to superpose a CryoEM map onto a Xray map.
I tried the "superpose maps" under the map section of phenix 1.14 but it only takes "reflections" and not the .mrc format  of the CryoEM map.
should I transform the CryoEM map into structure factors using "Map to structure factors" or is there a better way to do this?

you can try.. Yes, convert both maps into Fourier space equivalents and feed into the program. Note, you need  two models that fit two maps. The way it works is that it superposes models first, then applies corresponding operators (that superpose models) to maps. I can't remember anyone asking this questions before on this list or myself directly.

Share your experience!

Good luck,
Pavel


--

Vincent Chaptal, PhD

MMSB -UMR5086

Drug Resistance and Membrane Proteins Laboratory

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