Cornelius Krasel krasel at
Thu Apr 28 05:34:00 EST 1994

Laura Levy (levyl at wrote:
: i have a protein expressed in baculovirus and e. coli. although the protein 
: itself is the same size in both systems, the series and sizes of western 
: reactive smaller bands are different. i assume these are inherent differences
: in the way the protein is procesed in mammalian vs procaryotic systems.

E. coli is for example not able to glycosylate proteins. Therefore e.g.
membrane proteins expressed in E. coli are smaller than their eukaryotic
counterparts. Generally, proteins expressed in eukaryotes may be modified
in more different ways than in E. coli.

Another possibility for the protein to be smaller could be that the
protein is not correctly folded in E.coli and therefore more susceptible
to proteases. I wouldn't refer to this as processing, though :-)

You should probably check for the functionality of your protein in both
expression systems. If it is similar, proteolysis seems quite unlikely to


/* Cornelius Krasel, Abt. Lohse, Genzentrum, D-82152 Martinsried, Germany */
/* email: krasel at                 fax: +49 89 8578 3795 */
/* "People are DNA's way of making more DNA." (Edward O. Wilson, 1975)    */

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