> On 6 Feb 2026, at 11:12 AM, Catherine Back > <[email protected]> wrote: > > Hi All, > > Thank you so much to everyone for all the suggestions so far. In reply: > > The density appears to form a contiguous gap in the lattice (see image > attached). The channel just looks too big to be real (in my opinion). Why “too” big? If crystal contacts are there, and hold the crystal together, it may be a case of particularly high solvent content (there are several examples reported)
> I didn't loop/freeze the crystals so I can't tell you if they were > soft/fragile, but no one mentioned that to me. > Apologies for not mentioning - the res of the initially solved structure = > 2.3 Å. R factors for the almost complete structure were 0.22/0.27. These numbers, very roughly of course, sound like there’s nothing especially wrong with this model/structure. Not saying that you shouldn’t look for alternative space groups and/or better processing! Other colleagues have suggested very interesting approaches to do that. …but, maybe also keep an open mind as to the fact that your processing is OK, and that you REALLY have huge solvent channels in this crystal. > <…snipped...> > Contour level was probably around 1. ….again, maybe play around lowering this! Just to see whether you can make any sense of those Fo-Fc positive peaks (that seem like connected/continuous density) close to your current model. Do you have extra fragment(s) in your protein sequence that has(ve) not been modeled? Good luck! Alejandro > <…snipped...> ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a mailing list hosted by www.jiscmail.ac.uk, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/
