Francis, It can happened We have (not yet published) P1 with 24 molecules. When we cut His-tag we get P1 with 32 molecules. In our case we believe it is dictated by very strong interaction between two monomers, and strong interaction between dimers with build a flattish tetramer. Probably such formations is more difficult to oaks than globular oligomers. In this moment I do not recall what we see in solution, I have to check. Relating to structure solution, P1 is very convenient space group. I would go for determination this structure by SAD (SHELXC/D/E pipe, PHENIX or SHARP). For the native - molecular replacement. In our time after tremendous developments in Refmac and Phenix and development o DM refinement is 3-3.4 Ang. Is not very difficult. I would use in addition to NCS restraints in refinement also multi crystal averaging. Roumors say it is the most strongest phasing method (attributed to Eleanor Dodson, myself never used it).
FF Dr Felix Frolow Professor of Structural Biology and Biotechnology, Department of Molecular Microbiology and Biotechnology Tel Aviv University 69978, Israel Acta Crystallographica F, co-editor e-mail: [email protected] Tel: ++972-3640-8723 Fax: ++972-3640-9407 Cellular: 0547 459 608 On Jan 19, 2014, at 08:48 , Francis Reyes <[email protected]> wrote: > You sure about this space group? 24 monomers in P1 is unusual (at least to me) > > F > >> On Jan 18, 2014, at 9:14 AM, Chris Fage <[email protected]> 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>
