Dear community,

I would like to know the community opinion in a topicregarding the deposition 
of Pandda events maps as part of SF factors of thehits on deposition.

In a recent deposition, I was required by PDB to add to my SFfile a block 
containing ‘data for ligand evidence map’, aka Pandda event map,as this would 
be crucial for people to ‘reproduce my results’.

I found out in the hard way that converting .ccp4 to a .mtzis not a trivial 
task, as the first lack many crucial crystallographic information(such as 
symmetry and I/sig). Eventually, I found a way to do it (thanksTobias), by 
expanding original symmetry to P1, realign origin of the map and convertingwith 
phenix.map_to_structure_factors, which is quite a lot of work if you havemany 
hits. I’m sure this people in this BB would have better ways to do it (Iwill be 
happy to hear them), but this is not the goal of this post.

The goal is to bring to discussion the relevance of havingthe event map block 
added to the SF files in PDB. As I understand, this astatistical map calculated 
from averages of several datasets from your eventsearch, with the only goal of 
highlighting weak signals. The way I see it, thereis no crystallographic 
information at an event map that can be anyhow used forvalidation a structure 
(at least with our standard tools). Moreover, as this mapis calculated from a 
large set of datasets (mostly apo structures notdeposited), there is no way 
anyone would reproduce a given map without having accessto all the used files 
from pandda input (mostly apo structures that are not deposited).

On the other hand, there is of course the fact thatsometimes week events are 
hard to be proved only by the SF, and visualizationof the event map is keen for 
its confirmation.

So, my question is, is it worth it to having this informationattached to the SF 
files of the deposited ligand-bound structures? Maybe thereis a better way to 
do it. I though maybe if PDB allowed us to upload event mapsas ‘auxiliary 
files’, same way they do with cryoEM files (like masks, modifiedmaps, etc), so 
we can have our visual confirmation of the events if we wish,and at the same 
time not polluting our xray files with information that is notxray. 

I will be glad to hear about that from the communitie,

Thank you so much


Andre S. Godoy, PhD 

Universidade de São Paulo
Instituto de Física de São Carlos
Av. João Dagnone, 1100, Jd. Santa Angelina13563-120 - São Carlos, SP, Brazil 

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