Hi Anita,
I do not have much experience with detergents, but spherulites like you
showed often occur with proteins. Unfortunately, these things usually do
not diffract. On the other hand, they occur often in conditions close to
good crystallization conditions, so in your case I would try to optimize
the conditions (fine pH, precipitant screen, additives etc.). It does
not always work though.
I would also wash a number of shperulites and put them on a gel to see
if they contain protein.
Best,
Herman
________________________________
From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On
Behalf Of anita p
Sent: Sunday, May 06, 2012 1:46 PM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] detergent or protein
Hi All,
Thanks for your advices. I tried staining with izit dye, please
have a look at the attached image. The granules are all stained.
The detergent used here is Chaps (as an additive to
crystallization condition)
Does it look like protein ??
If yes, please do advice on methods to improve this.
I found granules in some other conditions as well and they
didn't stain with izit. So probably they were of detergent... Plz
suggest
Thanks in advance for suggestions
regards
Anita
On Fri, May 4, 2012 at 11:43 PM, John K Lee <kw...@msg.ucsf.edu>
wrote:
Hi Anita,
One question that comes up immediately is why you are
using DDM @ 5% concentration. If it's a typo, understandable. I figure
most of us use DDM at 0.05-0.1% concentration, and I've used as low as
0.015%.
Also, as others have pointed out, until you shoot it,
you don't know. But if it's hexaganol with very smooth/non-sharp edges,
many of us have seen it using DDM.
-john
On May 4, 2012, at 7:48 AM, anita p wrote:
> Hi All,
> I would like to have your expert advice on crystals.
> I am using detergents as 5% (w/v) of DDM 0.4ul in a
4ul (protein + condition + detergent). The precipitant is 28% peg 20K
> After 1 day I am able to see little plates of
irregular shape .
>
> I am able to see some needles if I change into
MEGA-10.
>
> I am able to see some hexagonal 3D crystals when I
change the precipitant to Ammonium sulphate and the detergent to
Anapoe-C10E6
>
> Is there a possibility to check whether this crystals
are protein or of detergent, even before shooting it ?
> Does the control drop test help ??
>
> awaiting for feedback
> Anita
