Introduction of a C-terminal hexa-lysine tag increases thermal stability of the LacDiNac binding adhesin (LabA) exodomain from Helicobacter pylori

Publication date: Available online 1 July 2019Source: Protein Expression and PurificationAuthor(s): Vasiliki Paraskevopoulou, Verónica García Artiaga, Rachel Rowlinson, G. Sebastiaan Winkler, Paul Gellert, Snow Stolnik, Ross Overman, Franco H. FalconeAbstractHelicobacter pylori is a pathogenic microorganism infecting approximately 50% of the global population, and establishes life-long colonization despite the hostile stomach environment. H. pylori employs a wide range of outer membrane proteins (adhesins) for epithelial attachment, which specifically bind to glycans or non-carbohydrate structures expressed on the gastric epithelium. A recently described adhesin from H. pylori is LabA, named after its ability to bind to a disaccharide present in gastric mucus (LacdiNAc-specific adhesin). Here, we describe the recombinant expression of LabA from H. pylori strains J99 and 26695 in E. coli. High yields of recombinant LabA were obtained using periplasmic expression. We found that the addition of a C-terminal hexalysine (6K) tag enhanced the thermal stability of LabA without affecting its secondary structure, using differential scanning fluorimetry and circular dichroism spectroscopy, respectively. In contrast to our previous report for another H. pylori adhesin (BabA), the 6K tag did not enhance recombinant protein yield or solubility. Both versions of LabA, with or without the 6K tag, were expressed and isolated from the periplasmic space of Escherichia coli, with a surprising...
Source: Protein Expression and Purification - Category: Biochemistry Source Type: research