In my experience translational NCS also can a part when one has many molecules in the a.u. If MR is an option, modern packages are rather good in dealing with TNCS. We used Molrep + Refmac at 3.x A (still unpublished) for a case with 18 complexes (36 monomers) in the a.u. and things weren't as bad as I originally thought.
BTW, we later made the construct 3 aa longer and we got 1 dimer in the a.u. with xtals diffracting to 2 A. I would consider playing a bit with your construct (not only the tag). Good luck! R On 18 Jan 2014, at 17:14, Chris Fage <cdf...@gmail.com<mailto:cdf...@gmail.com>> wrote: Hello Everyone, I am currently trying to phase a structure with an asymmetric unit predicted to contain 20-24 monomers (space group P1). The native crystals, while beautiful in appearance (see attached), only diffract to ~3.4-3.0 angstroms at best, and SeMet-derived crystals grow with poor morphology (small needles). Also, based a fluorescence scan, I know that mercury does not bind appreciably. Other than screening for a new space group, what options might I have for phasing this many monomers at lower resolution? Is there any real chance of solving the structure in this space group? Thank you in advance for any suggestions! Regards, Chris <Crystals.jpg> Roberto A. Steiner Group Leader Randall Division of Cell and Molecular Biophysics King's College London roberto.stei...@kcl.ac.uk<mailto:roberto.stei...@kcl.ac.uk> Room 3.10A New Hunt's House Guy's Campus SE1 1UL London Phone 0044 20 78488216 Fax 0044 20 78486435
