Re: [ccp4bb] non-diffracting xtals

2013-08-20 Thread Mahesh Lingaraju
Hi Evgeny I do have a few free cysteine residues but i am not sure if this is the problem in my case, I say that because i have crystallized this protein with another ligand without any issues and if oxidation of cysteine residues is a problem, i would imagine that it would have happened in the

Re: [ccp4bb] non-diffracting xtals

2013-08-20 Thread Eugene Osipov
Wow! Unexpected advices! Thank you very much, for addon and Fab! Ed, you are right in both cases: about my name and protease. I think it is good idea to try to screen for crystallization conditions with bME. Mahesh, I know nothing about your object, as well as buffer conditions. May be you would

Re: [ccp4bb] non-diffracting xtals

2013-08-19 Thread David Schuller
On 08/19/13 16:49, Mahesh Lingaraju wrote: Hello people I recently obtained hexagonal rod like crystals (150x50x20 um) which turned out to be non diffracting. What is the usual convention for cases like this ? do people usually give up on the condition or still try to optimize it ? It

Re: [ccp4bb] non-diffracting xtals

2013-08-19 Thread Mahesh Lingaraju
Hi Petri They are non-diffracting at the home source and they are cryo cooled. Like david suggested I guess ill try introducing a buffer as my condition does not have a buffer. it is ammonium acetate and PEG 3350. Thanks for the encouragement ! Mahesh On Mon, Aug 19, 2013 at 5:37 PM, Petri

Re: [ccp4bb] non-diffracting xtals

2013-08-19 Thread Bosch, Juergen
Well said Petri, also how much PEG3350 do you have in your conditions ? More than 25% ? I'm going after cryo-conditions at this point, you might want to replace your PEG3350 with smaller PEGs or a mixture of PEG400 and PEG3350. Almost sounds as if no optimization of the original conditions was

Re: [ccp4bb] non-diffracting xtals

2013-08-19 Thread Mahesh Lingaraju
Hi Jürgen you are right, I did not try any major optimization yet. I only tried to vary PEG and protein concentration. That did not really improve things too much. The protein mostly forms spherulites beyond 25% PEG. I am also thinking that these crystals are poorly diffracting/not diffracting as