Dear onetwo, Coot will open .mrc files. However, different programs often modify the header of the mrc file, which can cause problems. This recent paper gives more information about the standard format for mrc files and proposed extensions to it:
http://www.ncbi.nlm.nih.gov/pubmed/25882513 The sigma level you need to work at is very much map-dependent, and can change considerably within the map depending on local resolution differences. The following website should give you more information about model building and refinement into EM maps using CCP4 tools, and a tutorial is forthcoming: http://www2.mrc-lmb.cam.ac.uk/groups/murshudov/content/em_fitting/em_fitting.html. The ccp-em mailing list (http://www.ccpem.ac.uk/) is also a good place to ask for advice. Best wishes, Alan On 9 Apr 2015, at 19:48, onetwo <[email protected]> wrote: > Dear All, > > This is regarding the protein structure model building using the density > files or the .mrc file obtained by cryo-electron microscopy data. I want to > seek some help on how to visualize these files in COOT. I am working on mac > system and have recently installed CCP4 which has Coot- Dec 2014 version. > When I load mrc file in coot via > open map it gives error: map failed to open. > Then using the em2em program, i have been successful in converting it to > .ccp4 which I am able to open it in the coot. Please let me know if this the > way I am supposed to do it. > > I have one more query that may be very naive but at which sigma level one > should work towards these maps in coot ? > > I have read the paper by Brown et al, in ACTA D, 2015, they have mentioned the > tools for macromolecular model building and refinement into electron > cryo-microscopy and mentioned many useful tools in COOT like jiggle fit > etc for this. > So, if I can use ccp4 also in the same way like we do for crystallography and > do refinement after model building in coot.For information, the protein I am > working on has around 8A resolution. > > > Looking forward for the help and guidance. > > Regards > > Get your own FREE website, FREE domain & FREE mobile app with Company email. > Know More >
