Re: protein solution

[Laurence Pearl <l.pearl@icr.ac.uk>]

***  For details on how to be removed from this list visit the  ***
***    CCP4 home page http://www.dl.ac.uk/CCP/CCP4/main.html    ***



Have you checked whether the 'cloudiness' is crystalline ?

In my experience reversible 'precipitation' is a very good sign, and
temperature shifting a concentrated but dissolved protein solution is a damn
good way of crystallising it.


Lan Zhou wrote:

> ***  For details on how to be removed from this list visit the  ***
> ***    CCP4 home page http://www.dl.ac.uk/CCP/CCP4/main.html    ***
>
> Dear Experts:
>
> Pardon me for asking a non-CCP4 related question here.  But, I really feel
> somebody out there can help me solve my problem.
>
> I have a very-well expressed protein.  It is fine at both 4c and room
> temperature (rt) as long as its concentration is below 1 mg/ml.  If I
> concentrate the protein to 4 mg/ml or even 20 mg/ml or so, they are still
> fine at 4c.  However, the protein solutions become very cloudy if I
> transfer them to rt or 16c.  The protein solutions will turn to clear
> again after they are put back to 4c for a while.
>
> Is there anyone who has experience this before ?  What could be the
> problem ?  Does it mean something wrong with the protein folding ? Is
> there any suggestion ?
>
> Your help is really appreciated.  Thanks in advance.
>
> Lan Zhou

--

---------------------------------------------------------------------------
  Laurence H. Pearl

  Section of Structural Biology, Institute of Cancer Research
  Chester Beatty Laboratories,  237 Fulham Road
  London SW3 6JB, UK

  Phone +44-207-970 6045 : Secretary +44-207-970 6046
  FAX   +44-207-970 6051 : E-Mail l.pearl@icr.ac.uk
---------------------------------------------------------------------------
  " Live Simply and do Serious Things .. " - Dorothy Crowfoot Hodgkin
---------------------------------------------------------------------------