I've expressed a protein with a simple 6x His tag in a pET vector. The DNA sequence is correct and if expressed , the protein should give a band of 25KDa. I obtain a messy series of bands on Western blot (anti-His) at around 37KDa and a very faint band at 25KDa. What does this mean?
unexpected protein bandsrecombinant protein expr
Posted 11 December 2014 - 09:51 AM
It doesn't mean anything. Normally you need to purify the tagged protein. Multiple banding on a western blot can be the result of a number of things, the more common of which are: primary and/or secondary antibody concentrations wrong, secondary incubation too long, and not enough washing. Then you can get into things like not denaturing the proteins enough, too much denaturation (causing aggregation), too much protein loaded... etc.