Hi, I have difficulties to comprehend your description. I understand - most crystals grow in P21212, with cell a=140 , b=110, c=44 - some crystals grow in P21212, with cell a=110 , b=140, c=44 Is that correct? If so, can you refine the structures? To what R-values, at which resolution?
The sentence "i wonder if i am doing the correct thing by interchanging the axis" has one answer: as long as you can refine the model, in each case, to satisfactory R-values and get satisfactory maps at a decent resolution, you have done "the correct thing"! In that case, as Phil says, you might simply have two different crystal forms - although it seems unlikely that they share the space group and numerical values of cell parameters. But somehow I suspect also some other source of crystallographic confusion. Are you certain about the 90° rotations? Could it not be 180°? If the latter, it may be a case of alternate origins - try CCP4's csymmatch or phenix.find_alt_orig_sym_mate . best, Kay On Tue, 30 Dec 2014 16:56:03 +0000, <Thii Chand> <[email protected]> wrote: >Dear Dr.Evans, > >Thanks for your reply. > >The unit cell parameters are a=140 , b=110, c=44., Hence i am afraid, the >interchange couldn't have occurred due to similar a and b. I had performed >dehydration using PEG in the said case. I agree that dehydration or soaking >with ligand can hardly lead to the interchange of axis.But, what i find >difficult to understand is how come only in three out of nice >structures,interchange of cell axis occurs, where i had maintained similar >experimental conditions for all the nine cases. Is there any logical >explanation for this or am i doing something wrong? > >The sp group are P21212 in all the cases. > >Thanks in advance > >Regards, >T.chandran
