Sorry for sending two pictures.
Best regards, Dirk. Am 19.03.10 10:31, schrieb Dirk Kostrewa:
Dear Francis Reyes,from the self-rotation function at kappa=120 degrees, you can see that one threefold NCS axis is perpendicular to a crystallographic twofold axis. I haven't worked this out for your particular case, but the combination of a threefold (n-fold) NCS axis perpendicular to a crystallographic twofold axis creates three (n) NCS twofold axes (that can be viewed from both directions and in case of an uneven NCS axis appear "twice"). I've appended a schematic stereographic projection to make this a bit clearer (full dyad symbol crystallographic, open dyad and triangle symbols NCS, green circles positions above plane, red circles positions below plane created by crystallographic dyad, dashed lines help to visualize the NCS threefold, thick solid line crystallographic twofold, thin solid lines NCS twofolds).Good luck, Dirk. Am 18.03.10 16:03, schrieb Francis E Reyes:Hi all I have a solved structure that crystallizes as a trimer to a reasonable R/Rfree, but I'm trying to rationalize the peaks in my self rotation. The space group is P212121, calculating my self rotations from 50-3A, integration radius of 22 (the radius of my molecule is about 44). I can see the three fold NCS from my structure on the 120 slice, but I'm trying to rationalize apparent two folds in my kappa=180. A picture of both slices is enclosed. The non crystallographic peaks for kappa=180, P222 begin to appear at kappa=150 and are strongest on the 180 slice. My molecule looks close to a bagel (44A wide and 28A tall). The three fold NCS is down the axis of looking down on the bagel hole. I'm trying to find the two fold. I imagine it could be slicing the bagel in half (like to eat it for yourself) or slicing it vertically (like to share amongst kids) but I'm not exactly sure what's the best way to visualize this. Is there something easier than correlation maps with getax (since I have the rotation (polarrfn) and translation?). If you have an eye for spotting symmetry, Ill send the pdb in confidence. Thanks! FR--------------------------------------------- Francis Reyes M.Sc. 215 UCB University of Colorado at Boulder gpg --keyserver pgp.mit.edu --recv-keys 67BA8D5D 8AE2 F2F4 90F7 9640 28BC 686F 78FD 6669 67BA 8D5D-- ******************************************************* Dirk Kostrewa Gene Center, A 5.07 Ludwig-Maximilians-University Feodor-Lynen-Str. 25 81377 Munich Germany Phone: +49-89-2180-76845 Fax: +49-89-2180-76999 E-mail: kostr...@genzentrum.lmu.de WWW: www.genzentrum.lmu.de *******************************************************
-- ******************************************************* Dirk Kostrewa Gene Center, A 5.07 Ludwig-Maximilians-University Feodor-Lynen-Str. 25 81377 Munich Germany Phone: +49-89-2180-76845 Fax: +49-89-2180-76999 E-mail: kostr...@genzentrum.lmu.de WWW: www.genzentrum.lmu.de *******************************************************
Combination-Crystallographic-NCS.pdf
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