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 they might be growing from sub-microscopic spherulites ? Thanks for the insights
Mahesh On Mon, Aug 19, 2013 at 8:00 PM, Bosch, Juergen <jubo...@jhsph.edu> wrote: > 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 > performed yet. > > Plenty to do for you, also since you have some crystal use them for > seeding into your new screens. > > Jürgen > > On Aug 19, 2013, at 5:46 PM, Mahesh Lingaraju wrote: > > 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 Kursula <petri.kurs...@gmail.com>wrote: > >> Hi, >> >> non-diffracting on the home source or state-of-the-art synchrotron? >> Cryocooled or room-temperature? What happens if you change the buffer but >> keep your pH? etc etc... >> >> For an important project, one should never ever give up. >> >> Petri >> >> >> --- >> Petri Kursula, PhD >> project leader, adjunct professor >> Department of Biochemistry & Biocenter Oulu, University of Oulu, Finland >> Department of Chemistry, University of Hamburg/DESY, Germany >> www.biochem.oulu.fi/kursula >> www.desy.de/~petri/research >> petri.kurs...@oulu.fi >> --- >> >> >> >> >> >> On Aug 19, 2013, at 11:49 PM, Mahesh Lingaraju <mxl1...@psu.edu> 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 ? >> >> The crystals are also not very reproducible. I believe it is because of >> ammonium acetate in the condition causing fluctuations in the pH because of >> its volatility. Is there any way to work around such a problem ? >> >> Thanks >> >> Mahesh >> >> >> >> > > ...................... > 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 > > > > >
