Emma, You need to provide more information. Luckily, I222 is orthorhombic, so a* is along a, b* is along b, and c* is along c. This makes things so much easier to interpret. I hope the plotting conventions you used are typical: b along +y (North pole), a along +x (to the right), and c perpendicular to the page. Let us also assume that you have contours at every 10% of the origin peak height.
If so, my quick assessment is that there is not much. At each of the crystallographic axes in the chi=180 map, you see an origin peak arising from the crystallographic 2-fold symmetry; the mirror symmetry is expected with orthorhombic space groups. At ~45 degrees in the ac-plane there is a small peak that is ~40% of the origin peak. An interpretation is that there may be 2-fold NCS, with the axis ~45 away from the crystallographic a- and c-axes, but the noise across the map is kind of high. However, without more details about how you set the SRF up (data completeness, resolution, etc.), matthew's coefficient, and what you expect to see, little more can be done. Good luck, Michael **************************************************************** R. Michael Garavito, Ph.D. Professor of Biochemistry & Molecular Biology 603 Wilson Rd., Rm. 513 Michigan State University East Lansing, MI 48824-1319 Office: (517) 355-9724 Lab: (517) 353-9125 FAX: (517) 353-9334 Email: rmgarav...@gmail.com **************************************************************** On Feb 9, 2013, at 11:00 PM, Emma Littlejohn wrote: > Hi all, > > I have generated a self rotation function using MOLREP for a low res data set > which indexed in space group I222 (attached). I am hoping it may provide some > information on the oligomeric state of the protein. I am new to analysing SF > and was wondering if anyone can help with the interpretation or has any tips > that might be able to help me shed some light on what the SF is revealing? > > Thanks in advance. > Emma > > > <SF.jpg>
