Dear CCP4BB users: Thanks to Dr. Murshudov's instructions, I can now tie the waters to their original positions. There are 230 water mols in my model. I did:
1. make a file (eg harmonic.key) that says: external harmonic residues from 1 X to 230 X sigma 0.2 2. select harmonic.key in the "include keyword file" interface (after "PDB in", "PDB out" and "LIB in"). A sigma-value of 0.02 tied the waters closer to the original and a value of 2.0 shifted them as much as without the harmonic restraints. I got a slightly lower R-free by using 0.2. Looks like a good strategy, doesn't it? Ping +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ T z u - P i n g K o < [email protected] > Institute of Biological Chemistry Academia Sinica, Nankang, Taipei 11529, Taiwan Tel. +8862 2785 5696 ext 5011 FAX. +8862 2788 9759 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
