Hi all, Thanks a lot for the valuable suggestions.I have tried detwinning it but the detwinning program in CCP4 takes care of only merohedral data( if I am not wrong) and the other program( I guess Cell-now in Apex 2 by Bruker?) which takes care of non-merohedral twinning is not accessible to it( as I can't buy it). Also, the anomalous signal in the home source data is pretty weak. So, I was thinking about trying to get a better result by trying to merge the two data sets, though I am aware of the problem posed by twinning. But since we were not being able to get crystals of size mountable at home source, I thought why not try whatever is possible!
Thanking you, Regards, ARKO On Thu, Jan 19, 2012 at 10:13 PM, James Holton <[email protected]> wrote: > > Oh dear. > > You definitely cannot de-twin a dataset by mergeing it with a non-twinned > dataset! And if the twin fraction of your synchrotron set is much greater > than 0.3 then it is unlikely that you will be able to use the anomalous > differences to solve the phase problem. > > If I were you, I would focus on the non-twinned crystal system. You CAN > average anomalous differences across different crystals, provided they are > reasonably isomorphous. http://dx.doi.org/10.1107/S0907444910046573 > > And I should add the caveat that twinning is equivalent to > "non-isomorphism" until after you have solved the structure because it > dramatically changes the intensity you have available for any given hkl > index. > > -James Holton > MAD Scientist > > > On 1/19/2012 8:20 AM, arka chakraborty wrote: > > Hi all, > > Thanks for providing multiple solutions to my problem. Prof . Tim Gruene > and Prof. James Holton provided some nice solutions. However since the data > are collected from different crystals, I am not sure whether I can do MAD > phasing. My aim is to merge the two data-sets to circumvent the problem > posed by the fact that the synchroton data is twinned. So maybe merging the > data sets will provide better phases from SAD phasing? My main concern was > how to do scaling adjustments before using the data-sets together. > > Thanking you, > > Regards, > > ARKO > > On Thu, Jan 19, 2012 at 1:46 AM, Soisson, Stephen M < > [email protected]> wrote: > >> But if we were to follow that convention we would have been stuck with >> Multi-wavelength Resonant Diffraction Experimental Results, or, quite >> simply, MuRDER. >> >> >> >> -----Original Message----- >> From: CCP4 bulletin board [mailto:[email protected]] On Behalf Of >> Jacob Keller >> Sent: Wednesday, January 18, 2012 3:13 PM >> To: [email protected] >> Subject: Re: [ccp4bb] Merging data collected at two different wavelength >> >> This begs the question* whether you want the lemmings to understand >> you. One theory of language, gotten more or less from Strunk and >> White's Elements of Style, is that the most important feature of >> language is its transparency to the underlying thoughts. Bad language >> breaks the transparency, reminds you that you are reading and not >> simply thinking the thoughts of the author, who should also usually be >> invisible. Bad writing calls attention to itself and to the author, >> whereas good writing guides the thoughts of the reader unnoticeably. >> For Strunk and White, it seems that all rules of writing follow this >> principle, and it seems to be the right way to think about language. >> So, conventions, even when somewhat inaccurate, are important in that >> they are often more transparent, and the reader does not get stuck on >> them. >> >> Anyway, a case in point of lemmings is that once Wayne Hendrickson >> himself suggested that the term anomalous be decommissioned in favor >> of "resonant." I don't hear any non-lemmings jumping on that >> bandwagon... >> >> JPK >> >> *Is this the right use of "beg the question?" >> >> >> >> >> >> On Wed, Jan 18, 2012 at 1:57 PM, Phoebe Rice <[email protected]> wrote: >> >> >> >>> Can I be dogmatic about this ? >> >> >> >>I wish you could, but I don't think so, because even though those >> >>sources call it that, others don't. I agree with your thinking, but >> >>usage is usage. >> > >> > And 10,000 lemmings can't be wrong? >> >> >> >> -- >> ******************************************* >> Jacob Pearson Keller >> Northwestern University >> Medical Scientist Training Program >> email: [email protected] >> ******************************************* >> Notice: This e-mail message, together with any attachments, contains >> information of Merck & Co., Inc. (One Merck Drive, Whitehouse Station, >> New Jersey, USA 08889), and/or its affiliates Direct contact information >> for affiliates is available at >> http://www.merck.com/contact/contacts.html) that may be confidential, >> proprietary copyrighted and/or legally privileged. It is intended solely >> for the use of the individual or entity named on this message. If you are >> not the intended recipient, and have received this message in error, >> please notify us immediately by reply e-mail and then delete it from >> your system. >> > > > > -- > > *ARKA CHAKRABORTY* > *CAS in Crystallography and Biophysics* > *University of Madras* > *Chennai,India* > > > -- *ARKA CHAKRABORTY* *CAS in Crystallography and Biophysics* *University of Madras* *Chennai,India*
