Melody,
While Joe addressed the possible effects of detergents on the
crystallization of proteins, the possible effects (both negative and
positive) of detergents on proteins are quite variable. Often there
are no general rules except to avoid ionic detergents (from anionic
detergents like SDS or sarcoyl or cationic detergents like cetylamine-
Br). Also some zwitterionic detergents can become ionic at pH
extremes (<5 and >9).
As the effects are protein dependent, few general rules have
emerged. Sometimes nonionic detergents reduce aggregation or the
proteins are stable at high detergent concentrations (>1% w/w). For
others, they interfere with activity in the presence of small amounts
of detergents. For example, maltose binding protein, which is often
used as a fusion protein to aid in purification and to enhance
solubility, loses its capacity to bind to amylose columns in the
presence of many nonionic detergents. While one might suspect that
only glycoside detergents (like octyl glucoside or dodecyl maltoside)
might do this, the effect is more general. Hence, when we purify a
MBP fusion protein in the presence of nonionic detergents, we often
add a His-tag to circumvent this problem, if it arises.
The bottom line is that the solution effects of detergents are
protein dependent, and few general rules have emerged
Cheers,
Michael
****************************************************************
R. Michael Garavito, Ph.D.
Professor of Biochemistry & Molecular Biology
513 Biochemistry Bldg.
Michigan State University
East Lansing, MI 48824-1319
Office: (517) 355-9724 Lab: (517) 353-9125
FAX: (517) 353-9334 Email: [EMAIL PROTECTED]
****************************************************************
On Mar 14, 2008, at 9:59 AM, Becker, Joseph W wrote:
Helps sometimes, Start with:
A. McPherson, S. Koszelak, H. Axelrod, J. Day, R. Williams, L.
Robinson, M. McGrath and D. Cascio (1986) An experiment regarding
crystallization of soluble proteins in the presence of beta-octyl
glucoside. J Biol Chem 261:1969-1975.
Twenty-one soluble proteins, five tRNAs, and three protein-nucleic
acid complexes were studied in a systematic manner with regard to
their crystallization behavior from polyethylene glycol and
ammonium sulfate solutions in the presence of 0 to 1.5% beta-octyl
glucoside. Our observations suggest that this neutral detergent
does influence in a very positive way the growth characteristics of
the macromolecules included in this experiment. In general, more
reproducible and rapid growth was noted with an increased number of
large individual crystals at the expense of microcrystals. In
several cases, new crystal forms were discovered. Selected x-ray
diffraction analyses imply that crystals grown in the presence of
beta-octyl glucoside diffract as well or better than those grown in
its absence. In addition, a screen of two proteins grown in the
presence of 14 different common detergents suggested that a general
detergent effect may be beneficial for the growth of crystals of
biological macromolecules.
Then check out the detergent screens from Hampton and others
Joe Becker - Merck Research Labs
From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf
Of Melody Lin
Sent: Friday, March 14, 2008 9:40 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] normal protein in detergent?
Dear all,
sorry for the off-topic and possibly very naive question- but does
anyone know what happens if normal protein is put in detergent-
containing aqueous solution? how much detergent can a regular
protein tolerate? I was trying to search literature but couldn't
find any...
Thank you greatly for your attention and inputs.
Best,
Melody
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