Naive questions

[Axel T. Brunger]

>         I just subscribe to this list two minutes ago. So maybe my
> questions will be very naives, apology in advance.
>                 -  I'd like to select reflections at 3 sigmas cut-off
> between 8 and 3 A resolution, and 5 sigmas cut-off between 3 and 2.7 A
> resolution. How do I achieve that ?
>

resolution 8 3
do (fobs=fobs* heavy(fobs- 2 * sigma ) )

resolution 3 2.7
do (fobs=fobs* heavy(fobs- 2 * sigma ) )

...


>                 - I want to refine my B factors. I got a dimer in my
> asymmetric unit, each consisting in one protein and one tRNA.  I just want
> to refine the proteins atom's B factors. I didn't find a way using '
> optimize bfactor' to select only my protein. How can I do ? (every protein
> and tRNA have got a segid)
>

constraints fix=( select your atoms with fixed Bs) end

xrefin
   optimize B
 ...


Axel Brunger