Dear All,
I may be asking a dumb question and if so I apologize. I have a ~200 amino acid N-terminal 'arm' of a full protein (C-term already solved) that diffracts to ~2.1A. It integrates nicely in C2 and gives good molecular replacement models from Balbes in C121, 1I21, A121, C1211 and I1211 (>90% certain). Phaser gives nice hits in C2 and I2 but I have not been able to get it to accept the C1211 or I1211. It appears from refining the data that my solution is either C1211 or more probably I1211 unfortunately I am having problems using these two groups. In addition to this I also have some evidence of twinning L Molrep and Refmac will accept the I1211 and C1211 groups but the freer and uniquify components after Scala will not. I've used reindex with the space group as is, in brackets, and in the 'I 1 21 1' notation all to no avail. My refinements have been forced to use the mtz files output by the Balbes server which loose 50% completeness in these two cases. My current R and Rfree with this data are 27% and 38% and the overall chain that I have built is in good agreement with one of the SAXS envelopes I have, but the data completeness issue is causing me problems. Has anyone come across this, do I need to add a symm group to the existing groups? I seem to remember some issues with these a few years back but that part of my brain is too dusty at present! Thanks for any help and hopefully I will not be hitting my head against the wall with the obvious. Cheers, Eddie Edward Snell Ph.D. Assistant Prof. Department of Structural Biology, SUNY Buffalo, Hauptman-Woodward Medical Research Institute 700 Ellicott Street, Buffalo, NY 14203-1102 Phone: (716) 898 8631 Fax: (716) 898 8660 Skype: eddie.snell Email: [email protected] Telepathy: 42.2 GHz Heisenberg was probably here!
