Re: [ccp4bb] pseudotranslation issues
With that translational vector the data set is approximately I centred. If you integrate it in I centred lattice then you must consider space groups I 4 or I41. In point P4 you might need to consider SGs P4, P41, P42, P43 Eleanor On 1 July 2013 11:19, rajakumara eerappa reera...@gmail.com wrote: Dear Fulvio Saccoccia As you suspected it might be I4 instead of P4. Since fractional coordinates are (0.5, 0.5, 0.479) and, 0.479 is almost 0.5. Try to integrate and scale in I4 and see how chi-square behaves. Raj On Fri, Jun 7, 2013 at 11:17 AM, Fulvio Saccoccia fulvio.saccoc...@uniroma1.it wrote: Dear ccp4bb users, I have a data set collected at 2.2A resolution that I can integrate in P4. Aimless, Phaser and Xtriage recognized a pseudotranslation (34.6% of origin peak) at fractional coordinates 0.500 0.500 0.479 (ORTH 46.7 46.7 37.4). However labelit.index run with sublattice_allow=true search did not detect the pseudotranslation vector. So far, any attempts to phase by molecular replacement was unsuccesfull and I suspect that it could be due to incorrect assignement of space group: Now, some questions arise: 1) does the pseudo translation exist or do not? 2) if translational NCS is present, could it mimic a P41/P42/P43 space group? 3) in any case, any advices in order to properly deal with tNCS will be of great help? I thank you in advance Best wishes -- Fulvio Saccoccia, PhD Sapienza University of Rome Dept. of Biochemical Sciences A. Rossi Fanelli Piazzale Aldo Moro, 5 00185 Rome (Italy)
Re: [ccp4bb] pseudotranslation issues
Dear Fulvio Saccoccia As you suspected it might be I4 instead of P4. Since fractional coordinates are (0.5, 0.5, 0.479) and, 0.479 is almost 0.5. Try to integrate and scale in I4 and see how chi-square behaves. Raj On Fri, Jun 7, 2013 at 11:17 AM, Fulvio Saccoccia fulvio.saccoc...@uniroma1.it wrote: Dear ccp4bb users, I have a data set collected at 2.2A resolution that I can integrate in P4. Aimless, Phaser and Xtriage recognized a pseudotranslation (34.6% of origin peak) at fractional coordinates 0.500 0.500 0.479 (ORTH 46.7 46.7 37.4). However labelit.index run with sublattice_allow=true search did not detect the pseudotranslation vector. So far, any attempts to phase by molecular replacement was unsuccesfull and I suspect that it could be due to incorrect assignement of space group: Now, some questions arise: 1) does the pseudo translation exist or do not? 2) if translational NCS is present, could it mimic a P41/P42/P43 space group? 3) in any case, any advices in order to properly deal with tNCS will be of great help? I thank you in advance Best wishes -- Fulvio Saccoccia, PhD Sapienza University of Rome Dept. of Biochemical Sciences A. Rossi Fanelli Piazzale Aldo Moro, 5 00185 Rome (Italy)
[ccp4bb] pseudotranslation issues
Dear ccp4bb users, I have a data set collected at 2.2A resolution that I can integrate in P4. Aimless, Phaser and Xtriage recognized a pseudotranslation (34.6% of origin peak) at fractional coordinates 0.500 0.500 0.479 (ORTH 46.7 46.7 37.4). However labelit.index run with sublattice_allow=true search did not detect the pseudotranslation vector. So far, any attempts to phase by molecular replacement was unsuccesfull and I suspect that it could be due to incorrect assignement of space group: Now, some questions arise: 1) does the pseudo translation exist or do not? 2) if translational NCS is present, could it mimic a P41/P42/P43 space group? 3) in any case, any advices in order to properly deal with tNCS will be of great help? I thank you in advance Best wishes -- Fulvio Saccoccia, PhD Sapienza University of Rome Dept. of Biochemical Sciences A. Rossi Fanelli Piazzale Aldo Moro, 5 00185 Rome (Italy)
