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 ######################################################################## 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/
