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Dirk, I'm not sure this is right, the NCS 2-folds clearly occur at phi = 45, 135 ..., not at phi = 30, 150 ... as required by your explanation. Also you haven't explained the very clear peaks near theta = 45, phi = 0. 90 ... . I won't be convinced until I see the results from RFCORR! Cheers -- Ian On Fri, Mar 19, 2010 at 9:47 AM, Dirk Kostrewa <[log in to unmask]> wrote: > ... and here a slightly clearer version where I numbered the NCS-related > positions 1,2,3 and their crystallographic equivalent positions 1',2',3', > which makes the NCS dyads a bit easier to understand ... > > 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: [log in to unmask] > 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: [log in to unmask] > WWW: www.genzentrum.lmu.de > ******************************************************* >