Hi Humberto, I suggest that you try to use TLS in combination with group isotropic B (one B per residue). In my experience this almost always improves the model. It is important that you make a thoughtful decision about the TLS groups rather than refine the whole molecule as one TLS group (which is default). Pavel. On 4/29/2008 10:30 AM, Humberto Pereira wrote:

Dear all I was trying to refining a low resolution structure with Phenix. The crystal belongs to the SG P6122 with one monomer per ASU. The monomer contains approximately 270 residues. There isn't any NCS operators. The crystal diffracts up to 4.0 Angstrons, with good statistics, however I have only 4204 unique reflections. I solved the structure by MR by Phaser and the solution was quite reasonably. Initially I performed a phenix refining cicle with SA + rigid body, however the Rs values is very divergent (43 and 59%), so I decided to use the key xray_data.r_free_flags.ignore_r_free_flags=true in order to save my precious reflections with and without SA, and I also use the group_adp., in those cases the R is about 39-40%. I want a help to decide the best refinement strategies for low resolution refinement with phenix. BTW I'm trying to produce some different constructions of the gene, expecting improve the resolution.

Thanks Humberto

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