How to solublize bacterial membrane

Mario J. Borgnia mborgnia at welchlink.welch.jhu.edu
Fri Mar 21 10:25:19 EST 1997


On 19 Mar 1997, Alex Chang wrote:

> I am working with a recombinant protein which is expressed in the 
> periplasmic compartment of E. coli. Somehow, most of the expressed and 
> secreted protein is stuck with the bacterial membrane. So, I need to 
> solublized the membrane in order to isolate the recombinant protein.
> 
> I'd like to know if there are any detergent which can solublized the
> bacterial membrane, in the same time does not do much harm to the rProtein
> (I don't want to use guanidium HCl, for example). Will Triton X-100 do the
> job? 
> 
> 
> Alex Chang
> Pathology
> University of British Columbia
> alex at brc.ubc.ca
> 
> 

Several detergents are being used for extraction and functional
reconstitution of membrane proteins from bacteria (among other sources).
Those (mostly) non-ionic detergents are mild and will not affect (ideally)
the function of your protein. 
The selection of a detergent depends on the characteristic of your 
protein and it is usually an empirical process. First, go to the 
literature. Second, use the detergents that you can easily get, beginning 
with the less expensive.
What's the meaning of harming the protein for your purpose? The election 
of the detergent will depend also on the assays that you want to perform 
to your protein.


Here is a short list that may serve you as a guide: 

n-octyl-glucopyranoside (octyl-glucoside or OG): expensive
dodecyl-maltoside (DM): very expensive
CHAPS
CHAPSO
Triton X-100
NP40
deoxycholate
cholate
Sarkosyl (dodecylsarcosine)
Tween 20
Lubrol PX

There is a nice brochure published by CALBIOCHEM: "A Guide to the 
Properties and Uses of Detergents in Biology and BIochemistry".

Finally, how do you know that your protein is in the membrane fraction and 
not in inclusion bodies?


Mario J. Borgnia

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