Hi David - I think you have four hurdles to overcome:
1. How good is a SAXS envelope 2. How will you place it in the right place 3. How will you extend from ~15-20 A to around 4 A 4. How will you extend from 4 A to beyond Steps 2 and 4 might be the easiest - albeit far from trivial. Point 1 can be argued... However, I have not seen anyone cracking 3 in a convincing manner... (in the absence of serious NCS) I hope the next emails prove me wrong though! A. On 12 Mar 2012, at 21:10, David Briggs wrote: > Hi CCP4bb, > > I would like to ask about "envelope phasing" - specifically with SAXS data. > > There are papers (1) and tutorials (2) describing how this might be > done, but I have also found comments on the ccp4bb, such as this one > (http://www.proteincrystallography.org/ccp4bb/message11690.html) which > are somewhat less optimistic. > > I get the impression from my reading around that SAXS envelope phasing > is somewhat difficult to do unless you have some NCS you can use to > help the phase extension process. Does anybody have any > opinions/evidence/examples/anecdotes/tips about how SAXS envelope > phasing can be done successfully? > > Cheers, > > Dave > > (1) - eg - http://scripts.iucr.org/cgi-bin/paper?dz5081 > (2) - eg - > http://www.phaser.cimr.cam.ac.uk/index.php/Using_Electron_Density_as_a_Model > > ============================ > David C. Briggs PhD > Father, Structural Biologist and Sceptic > ============================ > University of Manchester E-mail: > david.c.bri...@manchester.ac.uk > ============================ > Webs : http://flavors.me/xtaldave > Twitter: @xtaldave > Skype: DocDCB > ============================
