Fengxia,
From the images it is clear that the degree of smearing is variable. From
this you can
deduce that you should be able to get sharp images by finding better
cryo-conditions.
There is no magic involved. Your crystallization conditions have little
precipitant
and a lot of water. Hence your problem. Increasing just the PEG
concentration may
induce a cell shrinkage and worsen the problem. On the other hand
replacing some of the
high molecular weight PEG 4K with a mixture of PEG10K + PEG200 + ethylene
glycol (EG) might
work. The higher MW PEG10K would better stabilize the crystals and the
PEG200/EG should provide
good cryoprotection.
Enrico.
>
> 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
>>
>>
>>
--
Enrico A. Stura D.Phil. (Oxon) , Tel: 33 (0)1 69 08 4302 Office
Room 19, Bat.152, Tel: 33 (0)1 69 08 9449 Lab
LTMB, SIMOPRO, IBiTec-S, CEA Saclay, 91191 Gif-sur-Yvette
Cedex FRANCE http://www-dsv.cea.fr/en/ibitecs/82
http://www.chem.gla.ac.uk/protein/mirror/stura/index2.html
e-mail: [log in to unmask] Fax: 33 (0)1 69 08 90 71
