Dear Smith, I think your question was clear, and the answer you got was clear as well.
However, I think the question you asked was not the right question. You want to use a particular phrase to describe your crystal packing and you want the CCP4BB to endorse this. When the answer was negative, you asked again the same question. The real question, in my eyes, is “What is the best way to describe my P65 crystal packing” since I guess you want to use this in your paper. Here I would use something like “in the crystal, the subunits are related by a 6-fold screw axis”. To be more precise, you could even mention a 65-screw axis. Other board members may even have better descriptions. By the way, 61, 62, 63, 64 and 65 axes are all 6-fold screw axes, but of different types. Best, Herman Von: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] Im Auftrag von Smith Lee Gesendet: Donnerstag, 19. Januar 2017 06:22 An: CCP4BB@JISCMAIL.AC.UK Betreff: Re: [ccp4bb] on space group Dear All, Here may I make my question much clear? For the space group P 65 crystal, it seems we can call it "6-fold packing of subunits around a screw axis in the crystal". Then for the space group P 64 crystal, can it also be called "6-fold packing of subunits around a screw axis in the crystal"? Smith On Thursday, January 19, 2017 11:50 AM, Ethan Merritt <merr...@u.washington.edu<mailto:merr...@u.washington.edu>> wrote: On Thursday, 19 January 2017 02:33:14 AM you wrote: > > Dear All, > In the literature, somebody call space group P65 crystal as "six fold screw > axis crystal packing", then I would not make any mistake if I call P64 space > group crystal also as "six fold screw axis crystal packing",am I right? > I am looking forward to getting a reply from you. > Smith "six-fold screw axis" refers to the symmetry. "crystal packing" refers to the molecule-to-molecule contacts regardless of symmetry. So no, I don't think "six fold screw axis crystal packing" makes any sense. -- Ethan A Merritt, Dept of Biochemistry Biomolecular Structure Center, K-428 Health Sciences Bldg MS 357742, University of Washington, Seattle 98195-7742
