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Hexahistidine (His6)-tag dependent protein dimerization: a cautionary tale.
1Department of Bacteriology, University of Wisconsin, Madison 53706, USA.
Acta Biochimica Polonica
|March 4, 2000
Summary
Hexahistidine (His6) tags can alter protein properties. This study shows His-tags partially restored dimerization in a mutant pi protein, highlighting potential impacts on protein behavior.
Area of Science:
- Biochemistry
- Molecular Biology
- Protein Engineering
Background:
- Hexahistidine (His6) tagged proteins are widely purified using Ni2+-NTA affinity chromatography.
- It is generally assumed His-tags minimally affect protein activity, efficiency, and specificity.
Purpose of the Study:
- To investigate if His-tags fundamentally alter protein biochemical properties.
- To examine the effect of His-tags on the dimerization and DNA-binding properties of pi(30.5) protein variants.
Main Methods:
- Studied variants of the pi(30.5) protein from plasmid R6K, a DNA-binding protein regulating plasmid replication.
- Assessed dimerization by observing binding to inverted repeats (IRs) in the pir operator.
- Utilized a monomeric mutant, pi200(30.5) (F107S substitution), to test His-tag effects.
Main Results:
- The His-tag partially restored the ability of the monomeric pi200(30.5) mutant to dimerize in solution.
- Dimeric binding of the His-tagged pi200(30.5) to IR sequences was observed, unlike the untagged mutant.
Conclusions:
- The presence of His-tags can fundamentally alter protein biochemical properties, specifically dimerization/oligomerization.
- Researchers should be aware that His-tagged proteins may exhibit different behaviors compared to their wild-type counterparts.