If you open the structures in Chimera, the "measure rotation" command will report the transformation matrix as well as the screw axis and shift/rotation along/around the screw axis needed. There are also options to that command for actually depicting the screw axis and/or rotation.
www.cgl.ucsf.edu/chimera www.cgl.ucsf.edu/chimera/current/docs/UsersGuide/midas/measure.html --Eric Eric Pettersen UCSF Computer Graphics Lab http://www.cgl.ucsf.edu On Jun 22, 2012, at 4:00 PM, Jeremy Tame wrote: > Yes, LSQKAB does, but not the equivalent screw axis (which exists by Chasles > theorem). I think a screw > axis may well be the best way to describe the rigid body movement which began > the thread. A simple > distance and angle (2 numbers) are easier to understand, and often of more > biological relevance, than > RT matrices, for example in the case of relative domain motions. > > On Jun 20, 2012, at 5:20 PM, Mark J van Raaij wrote: > >> LSQKAB ("superpose" in CCP4i GUI) also outputs in its log-file the >> translation parameters and rotation matrix it used to superpose the >> structure. >