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Thank you for the clarification. So you have two independent crystal forms from the 'same' condition and one of them does not grow in space. Sounds like there is some basis to the theory that lack of gravity caused the first form to disappear. Unfortunately it can also be the subtle changes in apparatus, differences for example how the temperature *varied* during incubation (yes, averaging on 20 but with what fluctuation and duty cycle, etc.) or the slightly different (differently aged even) batches of solution used for crystallization. When you say that you've not found any 'major' structural changes - did you find some 'minor' ones that are truly there (i.e. not artefacts of refinement with different resolution and data quality)? Are they interesting in any way? Otherwise it sounds like you've got the 'too many variables, but something is different enough to change the outcome' scenario that is oh so typical of crystallization, with a side note that space flight was one of the variables. In this case, I would avoid the term 'explain' and use 'rationalize' or 'speculate' instead :) Artem On Sun, Jul 10, 2011 at 2:56 PM, ferrol shariff <[log in to unmask]>wrote: > Thank you very much everyone for the replies. > > Ok. Here are more details on the work: > > 1) Crystallization was done using counter diffusion method- in a capillary > (for both Space and Ground experiments) > > 2) Vapor diffusion method was done only for Ground experiments, and > produced both Shape 1 and Shape 2 > > 3) The ground crystals usually grow in two forms- as nice single crystal > (Shape 1) and another one as needle-like long rods (Shape 2). > > 4) In space, only Shape 1 crystal was formed > > 5) Both Ground and Space experiments- temperature was fixed at 20 deg. > Space experiment- temperature was reported to us once a week. > > 6) Shape 2 crystals (the rods) diffracted much better, with much lower > mosaicity range, produced good data processing as compared to Shape 1 (Shape > 1 Space crystal's mosaicity range= 0.5-0.96! ) > > 7) Both Shape 1 and Shape 2 have different cell dimensions, with different > volumes (Shape 1= ~ 2X of Shape 2) > > 8) Both structures from Shape 1 and Shape 2- solved by molecular > replacement methods- no major structural changes between them > > Thank you. > > Regards, > > Fairolniza > > > p/s: And thank you, Dr. Snell for the paper. I already have the paper and > it has been one of my favorite references :) > > > > > On Sun, Jul 10, 2011 at 10:58 PM, Artem Evdokimov < > [log in to unmask]> wrote: > >> I would not rule out pure chance. Crystals of the same protein can and >> often do grow in two (or more!) different forms, from 'the same conditions' >> and often in the very same drop. In this case it's the same space group, but >> presumably different cell dimensions? Until a significant number of crystals >> from each condition (lab vs space) are analyzed, there's no reason not to >> believe that it was just luck :) >> >> Arten >> >> On Sun, Jul 10, 2011 at 9:53 AM, Jim Pflugrath <[log in to unmask]>wrote: >> >>> ** >>> OK, same space group, but you didn't indicate what the unit cells were. >>> They are different, right? >>> >>> ------------------------------ >>> *From:* CCP4 bulletin board [mailto:[log in to unmask]] *On Behalf Of >>> *ferrol shariff >>> >>> *Sent:* Sunday, July 10, 2011 3:10 AM >>> *To:* [log in to unmask] >>> *Subject:* [ccp4bb] Same protein, different molecule numbers per ASU >>> >>> Hello and good day to everyone! :) >>> >>> I have some general questions on crystallography work. I hope you don't >>> mind giving me some ideas. >>> >>> I have solved my lipase protein both ground-grown crystals and >>> space-grown crystals with good resolutions (1.4A and 2.2A). They are the >>> same protein from the same source, same purification methods, and produced >>> crystals from the same crystallization conditions (except the gravity >>> part). >>> >>> From the data, it shows that both of them belong to the same space group >>> P212121. But they have different number of molecule per asymmetric unit. >>> Ground crystal= 1 molecule/ASU, Space crystal= 2 molecules/ASU. At the >>> moment i have problem explaining this issue. Is it normal to have such >>> results? Same protein with different number of molecule/ASU? >>> >>> I've been trying to get some references on this matter but so far i don't >>> really get anything that can directly explain it. Furthermore, do i need to >>> relate this with the gravity effect? >>> >>> I hope you don't mind sharing some experiences on crystallography >>> especially regarding this matter. >>> >>> Thank you very much >>> >>> -- >>> FAIROLNIZA >>> >>> "The advantage of the emotions is that they lead us astray, and the >>> advantage of science is that it is not emotional" >>> -Oscar Wilde, The Picture of Dorian Gray, 1891 >>> >> >> > > > -- > FAIROLNIZA > > "The advantage of the emotions is that they lead us astray, and the > advantage of science is that it is not emotional" > -Oscar Wilde, The Picture of Dorian Gray, 1891 >