Thank you experts for your valuable suggestions. I think Ill try to solve it by proper data collection strategy the next time as i am unable to process my current data even with the tricks that were mentioned here.
Thanks again Mahesh On Fri, Aug 16, 2013 at 2:04 PM, Bosch, Juergen <jubo...@jhsph.edu> wrote: > tilted is what I meant at an angle of e.g. 30 or 60 degrees. Works fine > with most SSRL beamlines except of the 12-2 microfocus - but that might > have been fixed in the meantime. > > Jürgen > > On Aug 16, 2013, at 1:57 PM, Bosch, Juergen wrote: > > for #2) > > I'd suggest get some of those Mitigen loops that are titled. I assume you > have hexagonal plates as crystals and you really want to shoot along the > thin area of the crystal down the sixfold. With normal loops it's an art to > get that crystal to sit upright in the loop but not impossible if you take > smaller loops. > > My longest axis collected was 420 Å to ~2 Å resolution by this method. > > Jürgen > > On Aug 16, 2013, at 1:46 PM, Zbyszek Otwinowski wrote: > > This is clearly a case of a crystal with a very long unit cell; a case > which should be approached mindfully. > > HKL2000 has a default search for indexing solutions such that diffraction > along the longest unit cell will be resolved, with the assumed spot size. > > The problem with such diffraction has 2 aspects: > 1) how to process the already collected data where the spots are close to > each other; > 2) how to collect future data. > > Ad 1) The best solution is to reduce the spot size, so the spots are > resolved. This may require an adjustment of spot size by a single pixel; > one should not only change spot radius, but also change the box size > between even and odd number of pixels in the box dimensions. > > Just changing the spot radius changes the spot diameter by an even number > of pixels, so if one wants to change the spot diameter by one pixel, one > has to change the box size. This is the consequence of the spot being in > the center of the box. > > Just during indexing, there is also a workaround by specifying the command > before indexing: longest vector followed by a number that defines the > upper limit of the cell size. This may help finding indexing, but will > create overlaps between spots during refinement and integration. > > This dataset presents a problem of collecting data by rotating on the axis > perpendicular to the long unit cell. In consequence, the Image 1 has > essentially (barely differing in centroid position) overlapping spots, so > it would be hard to process them meaningfully by any program. > > Ad. 2) What would be a better way to collect data in the future? > > > Hi CCP4 folks > > > I have a data set which is looks twinned ( see the image-1 - I zoomed on > > to the image so that one can spot the twinning. Furthermore, the spots are > > very smeary from ~ 30 - 120 degrees of data collection, see image 2) I > > tried using HKL2000 and mosflm to process this data but i cannot process > > it. I was wondering if anyone has any ideas as to how to process this data > > or comments on whether this data is even useful. Also, I would really > > appreciate if someone could share their experiences on solving twinning > > issues during crystal growth > > > Thanks in advance ! > > > Mahesh[image: Inline image 2][image: Inline image 3] > > > > > Zbyszek Otwinowski > UT Southwestern Medical Center at Dallas > 5323 Harry Hines Blvd. > Dallas, TX 75390-8816 > Tel. 214-645-6385 > Fax. 214-645-6353 > > > ...................... > Jürgen Bosch > Johns Hopkins University > Bloomberg School of Public Health > Department of Biochemistry & Molecular Biology > Johns Hopkins Malaria Research Institute > 615 North Wolfe Street, W8708 > Baltimore, MD 21205 > Office: +1-410-614-4742 > Lab: +1-410-614-4894 > Fax: +1-410-955-2926 > http://lupo.jhsph.edu > > > > > > ...................... > Jürgen Bosch > Johns Hopkins University > Bloomberg School of Public Health > Department of Biochemistry & Molecular Biology > Johns Hopkins Malaria Research Institute > 615 North Wolfe Street, W8708 > Baltimore, MD 21205 > Office: +1-410-614-4742 > Lab: +1-410-614-4894 > Fax: +1-410-955-2926 > http://lupo.jhsph.edu > > > > >
