Dear Vito, The I3C isn't like the platins as a challenge to the 2Fo-Fc map. It maybe is more akin to the situation we described here:- https://onlinelibrary.wiley.com/doi/abs/10.1107/S0907444903004219 ie what does your Fo-Fc map, with three iodines placed, at the correct occupancy, look like? Best wishes, John
Emeritus Professor John R Helliwell DSc > On 10 Jun 2020, at 09:34, Vito Calderone <[email protected]> wrote: > > Dear Pierre, > I was in particular talking of 2FoFc refinement maps. > In the attached picture for example you can see the 2FoFc map contoured at 1 > sigma level of an I3C molecule bound to a protein where for I3C the only > visible density is that of iodines whereas the density of the other atoms of > the ligand is insignificant. > Best regards > > Vito > > -----Messaggio originale----- > Da: CCP4 bulletin board <[email protected]> Per conto di LEGRAND Pierre > Inviato: mercoledì 10 giugno 2020 09:31 > A: [email protected] > Oggetto: Re: [ccp4bb] Heavy atom vs light atoms density > > Dear Vito, > Could you precise in what kind of maps are you experiencing these effects: > 2FoFc refinement maps or experimental phasing ? > I had this kind of effects long ago in experiemental phasing due to Fourier > transform ripple effects. This could be due to scaling problems, low > resolution truncation or incompletness (maybe intensity overloads). > Another source condition could be local X-ray dose degradation due to the > high absoption of the metals. > Best regards, > Pierre Legrand > PROXIMA-1, SOLEIL > ________________________________________ > De : CCP4 bulletin board [[email protected]] de la part de Vito > Calderone [[email protected]] Envoyé : mercredi 10 juin 2020 08:42 À : > [email protected] Objet : [ccp4bb] Heavy atom vs light atoms density > > Dear All, > many of us have probably experienced that, in the diffraction > of protein ligands containing heavy atoms (cisPt, I3C, etc), the > overwhelming electron density of the metal can totally flatten that of the > light atoms around (or rather make it look insignificant). > Is anyone aware of an article/review (to use as a reference) in which this > is clearly stated/pointed out? > Best regards > > Vito Calderone > > > > ________________________________ > > To unsubscribe from the CCP4BB list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1 > > ######################################################################## > > To unsubscribe from the CCP4BB list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/webadmin?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/ > > ######################################################################## > > To unsubscribe from the CCP4BB list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/webadmin?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/ > <I3C_3.png> ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?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/
