Thanks, Ezra! I have a native dataset.
I'll try what you said, Hope it works in my case. Thanks! Alphar 2009/2/21 Ezra Peisach <epeis...@gmail.com> > Personally, I would try to build into what you see and then do phase > recombination. I had a SeMet crystal in which I could only see part of a > sheet and helix after DM... Things were not connected - until I improved > the phases with my model. Also - do you have a native dataset? You do not > mention it. > > Ezra > > > > Fengyun Ni wrote: > >> Hi everyone! >> I have a question on my poor MIR map. Four datasets (two AU and two HG) >> were used for phasing upto 3 A resolution in my case. I could locate several >> heavy atom sites for each dataset with occupancy finally refined to about >> 0.3 to 0.4, and with B value refined to about 50 to 80. I did not include >> the anomalous data because once I refine against anomalous data, the >> anomalous occupancy was only about 0.02, and even smaller as 0.004 for some >> sites. I guess the anomalous data are not good enough, so I did not use them >> right now (Could I do this? Or must I include them somehow?). >> The FOM I got is about 0.6, the Cullis-R factors were about 0.6 for all >> four data sets, and the phasing power was about 2.5 in each dataset. After I >> did the density modification, the FOM could increas to about 0.8. >> My problem is that the protein should form a long helix structure as >> indicated by other homology protein, but in the map after density >> modification, the densities are not consecutive though the overall shape >> seemed to be a long helix. The good thing is that some short helix-like >> densities could be observed in the current map, but they are not connected >> to each other. >> Right now, I am totally lost whether I should believe in the mir-map I >> have. Could I improve this map with some other method? Or should I re-do the >> phasing? >> BTW, the space group for my crystal is R3 or R32 with a=50, b=50, c=380, >> alpha=90, beta=90 and gamma=120. The c-axis is much longer than a- and >> b-axis, so the reflection data suffered from the anisotroy effect. >> Any suggestion on my phasing problem is welcome. >> -- >> Alphar Ni >> Call me alphar~ >> :) >> > > -- Fengyun Ni Call me alphar~ :)
