Re: [ccp4bb] bigger size - > better diffraction?

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: bigger size - > better diffraction?
From: Jenny ruisher {- at -} GMAIL {- dot -} COM
Date: 2007-04-04

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Subject: POSTDOCTORAL POSITION IN PROTEIN COMPLEX CRISTALLOGRAPHY
From: Vanessa Llobet vllobet {- at -} IBMB {- dot -} CSIC {- dot -} ES
Date: 2007-04-04

Subject: Re: bigger size - > better diffraction?
From: Jenny ruisher {- at -} GMAIL {- dot -} COM
Date: 2007-04-04

oh, One thing forgot to mention is that I actually collected data in
house ( about 70 frames ), the completness is high ( 98%) but the
Rmerge is high ( 0.2 ), what does this suggest?

On 4/4/07, Jenny wrote:
> Hi, All,
>
> I got a crystal that diffracts at 3.3A in house.The crystal size is
> about 0.2mm* 0.1mm * 0.2mm. At first I thought the size is fine,but it
> turns out the smaller ones diffract worse.I guess the reason is that
> the cell unit is really big (126.292 126.292 134.904 p4212,
> pretty big for a 10kD protein, isn't it?)
>
> So looks like I need to grow bigger crystals in order to get better
> diffractions.The problems is ,every time when I set up trays, the
> growing conditions is not exactly the same, so I have to set up a
> whole tray or maybe even 2 trays , then 2 or 3 conditions will jump
> out with good crystals ( 2 or 3 nucleation site ) and some of the
> others will show lots lots of small crystals.I used NaCl as the salt,
> in a 4*6 tray, the [NaCl] is going from
> 2.0,2.05,2.1,2.15,....something like that and 0.05M does make big
> difference.I used Urea as the additive in this case ( 25 m ~ 100 mM)
> and tried 2+2,3+1,3+2, 3+1 ( 3 uL protein and 1 uL buffer ) is better
> than the other two cases.Right now it's growing in room temp in about
> a week.And crystals that not fresh got some bubbles around the edge
> and didn't diffract well.
>
> Does anyone have any suggestions that what I could do to improve the
> diffraction?
>
> Thanks a lot.
>
> Jenny
>

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: bigger size - > better diffraction?
From: Jenny ruisher {- at -} GMAIL {- dot -} COM
Date: 2007-04-04

Next message:
Subject: POSTDOCTORAL POSITION IN PROTEIN COMPLEX CRISTALLOGRAPHY
From: Vanessa Llobet vllobet {- at -} IBMB {- dot -} CSIC {- dot -} ES
Date: 2007-04-04