Fengxia,
To me the diffraction appears as if the crystals did not freeze well.
So the best option seems to be annealing (as already suggested) or to
try different cryo-protectants.
Did you perform a room-temperature mount? If so, were the spots nice
and round (suggesting the cryo is the cause of the smears)?
I would suggest growing your crystals in the presence of cryo as well.
Glycerol, PEG 400, all the usual suspects.
May I suggest 2-methyl-2,4-pentanediol (MPD). I have had success
adding to well (10 - 20 %) but not in crystal drop, then using 20% as
a cryo (MPD acting to slow diffusion to give better ordered crystals).
Kelly Daughtry
*******************************************************
Kelly Daughtry
PhD Candidate
Department of Physiology and Biophysics
Boston University School of Medicine
590 Commonwealth Ave
R 390
Boston MA, 02215
(P) 617-358-5548
*******************************************************
On Thu, Jan 21, 2010 at 9:07 AM, Brad Bennett <[log in to unmask]> wrote:
> Hi Fengxia-
> How about increasing the PEG% so you don't have to add as much "other"
> cryoprotectant?
>
> Also, have you tried annealing the crystals? I've had success with this when
> I've had samples diffract similarly. The simplest way is by blocking the
> cryostream for 2-3 seconds (repeat 1-2 times) and then shoot. More involved
> way is by actually dismounting your crystals back into cryo buffer for 20-30
> seconds, then remounting and shooting.
>
> HTH-
> Brad
>
> On Thu, Jan 21, 2010 at 1:54 AM, Fengxia Liu <[log in to unmask]> wrote:
>>
>> Dear all,
>>
>> I am trying to diffract one semet-protein, it gave me some clear spots and
>> some smeared spots in one diffration, you can find maps attached.
>> Mother liquor condition is 0.1MTris-HCL pH8.5+10% PEG4k + 0.2M Li2SO4, I
>> have tried mother liquor+25%glycerol, paratone, paratone+ mineral oil, but
>> they all gave me such pattern.
>> Does anyone know how to solve this? I appreciate any advice.
>>
>> Thank you in advance.
>>
>> Best wishes,
>> Fengxia
>>
>>
>
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