Hi Partha, You can use phaser to choose what is sulfur and what is selenium. Try something like this: phenix.autosol 3 Se data=sad.sca seq_file=seq.dat \ sites_file=shelx.pdb \ mad_ha_add_list="S" \ mad_ha_add_f_prime_list="0.3" \ mad_ha_add_f_double_prime_list="0.3" Phaser will first locate Se atoms (and add any to your shelx list if appropriate), then it will look for S atoms as well. All the best, Tom T

Hiya,

I have a SAD dataset collected at 0.979A to very good completeness and redundancy, upto 2.1A. Two molecules in AU, each containing 2 Se and the solvent content is 40%. The Signal to noise is more than 1 upto 2.1A , however solve resolve and phaser did not work.

I am not an expert but what is getting somewhere is if I use SHELEX (or hyss) to find the sites, pick the best 3 of them, use MLPHARE or so to refine and Addsolve to find the other Se. However, looks like the fourth Se is less ordered. Now, the SHELEX file also finds several others which I guess are Sulphurs. I can see helix like density in the map after Addsolve (& resolve) or SHELEXE but have not been able to place any aromatic residue yet. I guess one problem is lack of proper NCS and low solvent content.

Could someone point me to a method in which I can improve the map by including the Sulphurs? For example, using the already found Se as seeds? I am trying the autosol option anyway.

Cheers, Partha _______________________________________________ phenixbb mailing list [email protected] http://www.phenix-online.org/mailman/listinfo/phenixbb