I have also observed this. In my cases I have also been able to get away
with using less cryoprotectant when freezing in the cryostream.
--paul
Daniel Pomeranz Krummel wrote:
> Dear Sajid,
>
> I have observed a consistent reduction in mosaicity (from approx. 0.95 to
> 0.45) for one case by freezing the crystals in a cryostream (N2 vapour) as
> opposed to submerging in liquid nitrogen.
>
> Have others observed this?
>
> Daniel
>
>> Dear All
>>
>> My protein size is ~30kD and crystallizes with
>> 19%Peg3350, 0.2M Nacl, and 0.1M Na Cacodylate buffer.
>>
>> Please refer the attached crystal image with this. The
>> crystal looks like good enough for home source. These
>> crystals appears in 4-5 days at room temp.
>>
>> Sometimes I'm getting crystals like this, but very few
>> in 24 well tray. Most of the time, I found the drop
>> contains needles. If I reduce the precipitant little
>> bit, I wont find any change in the drop even after
>> long time. Changing pH (or temp)of the buffer does not
>> help me any better. The crystal appears only around
>> 5.5pH.
>>
>> The problem is mosaicity. This crystal diffracted in
>> home source upto 3.2A and the mosaicity is 2.5degree.
>> Almost all the good crystal like this having same
>> mosaicity.
>>
>> Good cryo condition so far that I found was
>> 10%Glycerol with mother liquor. Other conditions
>> weekens the diffraction quality or increase mosaicity.
>>
>> In many crystal I could see some crack in the middle
>> of the crystal, it looks like twin crystal. Or the
>> crystal appears with some sattelite crystals.
>>
>> Can anyone suggest me some good way to overcome these
>> problems.
>>
>> Thankz
>>
>> Sajid
>>
>>
>>
>> From Chandigarh to Chennai - find friends all over India. Go to
>> http://in.promos.yahoo.com/groups/citygroups/
>>
>
>
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