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Dear all,
Recently we have collected one set of data which is processed to 2.9A and 3.0A and the Wilson-B values are 50.1 and 59.1, respectively. As for the completeness of the highest shell is only 66% in 2.9A (80% in 3.0A), we use the dataset with 3.0A for phasing and refinement.
Everything is OK during phasing. Routinely, we use CNS (rigid, minimize and bgroup) for primary refinement and the R and freeR values go to 31.1 and 34.1. Surprisingly, the B-factor is 137.2. I have modified the B-factor to a fixed value (59.1 A^2) in the searching model coordinate file, however it changed to 127.6 after 'rigid' and subsequently to 131.9 after 'minimize'. In all the scripts above I used the default option "anisotrpic" at "overall B-factor correction". I don't know whether it is right to use this option at low resolution, so I have tried the other two options "no" and "isotropic". In the 1st choice, the B-factor is seemingly reasonable (55~59) but the R and freeR are very high (45.9 and 51.9). In the 2nd choice, the B-factor, R and freeR values are between those of the other two options (111.3, 40.6, and 45.3). I want to know what cause these surprising changes especially for B-factor value.
Any suggestion is appreciated.
Jian Wu
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Jian Wu
Ph.D. Student
Institute of Biochemistry and Cell Biology
Shanghai Institutes for Biological Sciences
Chinese Academy of Sciences (CAS)
Tel: 0086-21-54921117
Email: [log in to unmask]