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 <jim.pflugr...@rigaku.com>wrote: > ** > OK, same space group, but you didn't indicate what the unit cells were. > They are different, right? > > ------------------------------ > *From:* CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] *On Behalf Of > *ferrol > shariff > > *Sent:* Sunday, July 10, 2011 3:10 AM > *To:* CCP4BB@JISCMAIL.AC.UK > *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 >
