I agree with Phil. A P2 crystal with nearly perfect noncrystallographic translational symmetry (~1/2,~1/2,0) will look like a C2 cell with twice the length along a and b and weak spots between the indexed spots. Look for those spots on your "C2" images.
Dale Tronrud On 11/9/2017 3:06 AM, Phil Evans wrote: > You should look critically at the indexing of the images for both cases. Does > the lattice interpret all spots, or are half of them missing > > >> On 9 Nov 2017, at 10:02, Markus Heckmann <[email protected]> wrote: >> >> Dear all, >>> From a small protein, gives crystals P2 with cell >> Cell 53.16 65.73 72.89 90 110.94 90 >> (has 3 molecules in the asymmetric unit). Tested with pointless. Does >> not give any other possibility. >> >> Another crystal if the same protein, similar conditions: >> C2 >> Cell 109.14 124.37 73.42 90 111.75 90. This has 6 >> molecules in the a.s.u. Tested with pointless. Does not give any other >> possibility. >> The cell length a, b of C2 is twice that of P2. >> >> Is it usual to get such crystals from similar conditions or am I >> missing something? >> >> Many thanks, >> Mark >
