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 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/
