Selenium

Paul Carr pdc at rsc.anu.edu.au
Sun Feb 25 21:32:44 EST 2001


G'day CNS/X-PLORers,

I am refining a seleno-methionine substituted protein structure using 
CNS.  We obtained good MAD phases and the refinement has not been 
problematic.  However when I calculate (mFo - DFc, phi-calc) maps the 
Se atoms have negative density around them.  I am using the default 
scatter.lib file distributed with the program.

Do other people see this phenomenon?  Do I need to put in different 
scattering terms for Se when working at the absorbtion edge? If so 
does someone have them available?

Thanks in advance.
Paul

  __________________________________________________________________________
|                                                 |                        |
|       __  L                                     |                        |
|    ,~'  L_|\    Dr Paul D. Carr                 | tel: +61 26-125-3766   |
| ,-'         \   Research School of Chemistry,   | fax: +61 26-125-0750   |
| (            \  Australian National University, |                        |
| \    ___   + /  Canberra, ACT 0200              | e-mail:                |
|  L,~'   "\_,/   AUSTRALIA                       |   pdc at rsc.anu.edu.au   |
|            u                                    |                        |
|_________________________________________________|________________________|


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