A simple method for non-denaturing purification of biotin-tagged proteins through competitive elution with free biotin

Abstract

The use of avidin or streptavidin in the purification of biotinylated proteins has been highly restricted due to the harsh and denaturing elution conditions. Here, we use biotinylated bovine serum albumin as a working model to demonstrate a simple and rapid method for biotin-tagged protein purification under non-denaturing conditions. The biotinylated bovine serum albumin is specifically bound to the anti-biotin antibody agarose beads and competitively eluted with free biotin under near-neutral conditions. The optimized elution conditions include using 4 mg/ml biotin (pH 8.5) as the elution buffer and allowing the buffer to incubate with agarose beads for 30 min prior to elution. The elution recovery rate is over 85% without apparent protein denaturation. The method is applicable for both immunoprecipitation and column chromatography.

METHOD SUMMARY

We describe a method for the purification of biotin-tagged proteins under non-denaturing conditions with no change in protein natural structure or function. Anti-biotin antibody agarose is employed to specifically bind the biotinylated proteins, followed by competitive elution with free biotin at near-neutral conditions. This approach is applicable for both immunoprecipitation and column chromatography.