Hi Kai, I think you may ask Dr. Qingping Xu at GM/CA at APS. He wrote a program to solve this kind of problem before.
Best regards, Kevin Jin On Sat, Jul 11, 2026 at 5:55 AM PIETRO ROVERSI < [email protected]> wrote: > Dear Kai, > > How many KDaltons in the asymmetric unit? > > P > > Dr. Pietro Roversi, PhD > Italian National Research Council (CNR) > Institute of agricultural biology and biotechnology (IBBA-CNR) > Via Bassini 15, 20133 Milano, Italy (ma: ingresso, visite e merci: Alfonso > Corti 12) > > Tel. +39 02 23699428 > Mobile +39 351 6800096 > Fax: +39 02 23699411 > https://ibba.cnr.it/en/staff/pietro-roversi/ > > Honorary Lecturer at LISCB - Department of Molecular and Cell Biology > Leicester University, Lancaster Rd. > Leicester LE1 7HB, England, UK > Tel. +44 7927 952047 > Email: [email protected] > URL: > https://le.ac.uk/research/institutes/structural-chemical-biology/people > ------------------------------ > *Da:* CCP4 bulletin board <[email protected]> per conto di > [email protected] <[email protected]> > *Inviato:* sabato 11 luglio 2026 13:40 > *A:* [email protected] <[email protected]> > *Oggetto:* [ccp4bb] SAD > > Dear all, > I am currently processing a SAD dataset collected from a Se-Met > derivative. According to the matthews_coef calculation in CCP4, there > should be 20 heavy atom sites in the asymmetric unit. > However, due to the very weak anomalous signal, the occupancy refinement > in SHELX shows only one site with an occupancy above 1.0, one site around > 0.4, and the remaining 15 sites all converging to approximately 0.3. > Given this situation, I would be very grateful for any suggestions on how > to obtain reliable initial phases. Are there any specific strategies, > software settings, or alternative approaches (e.g., density modification or > partial structure refinement) that you would recommend to make the most of > this weak signal? > Thank you in advance for your time and insights. > Best regards, > Kai Zhang > > > ------------------------------ > > To unsubscribe from the CCP4BB list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 > > ------------------------------ > > To unsubscribe from the CCP4BB list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 > ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a mailing list hosted by www.jiscmail.ac.uk, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/
