Increased adsorption of histidine-tagged proteins onto tissue culture polystyrene

In this study we compare histidine-tagged and native proteins with regards to adsorption properties. We observe significantly increased adsorption of proteins with an incorporated polyhistidine amino acid motif (HIS-tag) onto tissue culture polystyrene (TCPS) compared to similar proteins without a HIS-tag. The effect is not observed on polystyrene (PS). Adsorption experiments have been performed at physiological pH (7.4) and the effect was only observed for the investigated proteins that have pI values below or around 7.4. Competitive adsorption experiments with imidazole and ethylenediaminetetraacetic acid (EDTA), as well as adsorption performed at different pH and ionic strength indicates that the high adsorption is caused by electrostatic interaction between negatively charged carboxylate groups on the TCPS surface and positively charged histidine residues in the proteins. Pre-adsorption of bovine serum albumin (BSA) does not decrease the adsorption of HIS-tagged proteins onto TCPS. Our findings identify a potential problem in using HIS-tagged signalling molecule in assays with cells cultured on TCPS, since the concentration of the molecule in solution might be affected and this could critically influence the assay outcome.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Adding a histidine tag to a protein can have a high effect on the adsorption characteristics of the protein. ► Dependent on the pI value of the protein, the protein with a histidine tag shows a higher adsorption on TCPS compared to the protein without the tag. ► Electrostatic interaction between carboxylate groups on TCPS and histidine residues in the protein cause the change in adsorption characteristics.