If I remember for coefficients with FOM and a precise PHI calculated, A = FOM*cos(phi) B = FOM*sin(phi) C=D=0
If you have a probability curve for PHI. 0 to 360 such as you get from experimental phasing, A B C D mirror this bimodal curve better .. On Fri, 9 Feb 2024 at 09:58, Nitin Kulhar < 00009dfccc771c91-dmarc-requ...@jiscmail.ac.uk> wrote: > Dear sir > > Thank you for clearing that. I checked back to see that HLC/D are > invariably 0 for all reflections, with the non-zero HLA/B supposedly having > been originated from the probability distribution of phases *calculated* > by phaser. Hopefully, I have not misunderstood it. > > Thanks and regards > Nitin Kulhar > > On Thu, Feb 8, 2024 at 9:07 PM Randy John Read <rj...@cam.ac.uk> wrote: > >> Hi, >> >> Hendrickson-Lattman coefficients are just a way of storing phase >> probability information, and they can come from different sources including >> atomic models. Phaser puts in HL coefficients because they could be handy >> under some circumstances for combining the phase information from >> experimental phasing. You might notice that only A and B are non-zero for >> the molecular replacement HL coefficients. That’s because the phase >> probability distribution is unimodal for calculated phases, whereas it’s >> generally bimodal for experimental phases (thus requiring more >> coefficients). >> >> Best wishes, >> >> Randy Read >> >> > On 8 Feb 2024, at 14:32, Nitin Kulhar < >> 00009dfccc771c91-dmarc-requ...@jiscmail.ac.uk> wrote: >> > >> > Dear all >> > >> > Is anomalous diffraction necessary for determining experimental phases >> and the Hendrickson-Lattman coefficients (HLA, HLB, HLC, and HLD)? >> > >> > MR solution from Phaser 2.8.3 (interfaced in ccp4 8.0.000 suite) seems >> to be generating HLA/B/C/D coefficients from an x-ray diffraction dataset. >> > >> > Wavelength: >> > 1.54179 Angstrom. >> > >> > Sample: >> > • >> > Protein-small molecule ligand complex crystal. >> > • No anomalous scatterer in the protein, the ligand, or the >> crystallization condition. >> > >> > Data reduction: >> > Xtriage and aimless analyses did not indicate significant anomalous >> signal. >> > >> > I would appreciate any help in understanding the reasons for these >> observations. >> > >> > Thanks and regards >> > Nitin Kulhar >> > PhD student >> > c/o Dr Rajakumara Eerappa >> > Macromolecular Structural Biology Lab >> > Department of Biotechnology >> > Indian Institute of Technology Hyderabad >> > Kandi, Sangareddy >> > Telangana, India - 502284 >> > >> > Disclaimer:- This footer text is to convey that this email is sent by >> one of the users of IITH. So, do not mark it as SPAM. >> > To unsubscribe from the CCP4BB list, click the following link: >> > https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 >> >> ----- >> Randy J. Read >> Department of Haematology, University of Cambridge >> Cambridge Institute for Medical Research Tel: +44 1223 336500 >> The Keith Peters Building >> Hills Road E-mail: >> rj...@cam.ac.uk >> Cambridge CB2 0XY, U.K. >> www-structmed.cimr.cam.ac.uk >> >> > Disclaimer:- This footer text is to convey that this email is sent by one > of the users of IITH. So, do not mark it as SPAM. > > ------------------------------ > > 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/
