title: Stability towards alkaline conditions can be engineered into a protein ligand.
abstract: One of the problems with a proteinaceous affinity ligand is their sensitivity to alkaline conditions. Here, we show that a simple and straightforward strategy consisting in replacing all asparagine residues with other amino acids can dramatically improve the chemical stability of a protein towards alkaline conditions. As a model, a Streptococcal albumin-binding domain (ABD) was used. The engineered variant showed higher stability towards 0.5 M NaOH, as well as higher thermal stability compared to its native counterpart. This protein engineering approach could potentially also be used for other protein ligands to eliminate the sensitivity to alkaline cleaning-in-place (CIP) conditions.
authors.affiliation: Department of Biotechnology, Royal Institute of Technology, SE-100 44, Stockholm, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Gülich
authors.forename: M
authors.initials: M
authors.lastname: Linhult
authors.forename: P
authors.initials: P
authors.lastname: Nygren
authors.forename: M
authors.initials: M
authors.lastname: Uhlén
authors.forename: S
authors.initials: S
authors.lastname: Hober
mesh_terms: D000595:Amino Acid Sequence; D001216:Asparagine / Q000737:chemistry; D001483:Base Sequence; D002942:Circular Dichroism; D017931:DNA Primers; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D015202:Protein Engineering; D011506:Proteins / Q000737:chemistry* / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012972:Sodium Hydroxide / Q000737:chemistry*
chemical_list: D017931:DNA Primers; D011506:Proteins; D012972:Sodium Hydroxide; D001216:Asparagine