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Re: SnB & SeMet

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Dear All, and especially Dirk,

Well, Dirk, you should have gone to the SnB workshop in Buffalo!

First off, I hope you are using the latest SnB 2.0 beta from the ftp site:
Ftp nexus.hwi.buffalo.edu, login anonymous, cd pub, and get either
snb2.sgi.tar.gz or snb2.linux.tar.gz or snb2.alpha.tar.gz. Unzip, untar,
and follow the installation instructions.

Second, make sure you choose an appropriate interpeak  and symmetry
distance so that you don't have problems with the symmetry mates. At least
5 Angstroms- think about how big a Se is and how close they are likely to
be. The program assigns scattering factors for you.

For n seleniums, use:
20-40 n phases
200-400n triplets
search for n peaks
do 2n cycles, at least
use 2 90 degree parameter shifts.

Given good complete data it should work. The example that comes with the
program has 2.8 Angstrom data. The most important parameter for success is
probably the interpeak distance.

Good luck,


Lisa Edberg (205)934-1611 FAX:(205)934-0480
Center for Macromol. Cryst., Univ. Alabama-Birmingham
"Mathematics is a way to see structures that are there-
all ready to help you if only you can see them." Gerard Bricogne