Dear Kai,
What Artem refers to as "Bricogne's phasing suite" is the same
thing as the SHARP/autoSHARP package that Pietro Roversi was pointing
you towards (thank you Pietro and Artem :-) ).
If things don't work out, the problem is more likely to reside in
the SAD data themselves rather than in choosing the right program.
There are many ways of doing bad SAD experiments. We would be happy to
help you (off-line) determine whether this is the case, and to advise
you on how to do a better experiment.
With best wishes,
Gerard.
--
On Sat, Jul 11, 2026 at 08:59:15AM -0400, Artem Evdokimov wrote:
> I assume modeling with AF or Boltz does not provide useful model?
>
> You can try cross mapping Met residue positions from model on to your xray,
> first.
>
> Then try Bricogne's phasing suite and Solve, sometimes Shelx is not the
> best :)
>
> Artem
>
> - Cosmic Cats approve of this message
>
> On Sat, Jul 11, 2026, 08:55 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
> > <https://www.google.com/maps/search/Via+Bassini+15,+20133+Milano,+Italy?entry=gmail&source=g>
> > (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
> >
> >
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