title: The β1 domain of protein G can replace the chorismate mutase domain of the T-protein.
abstract: T-protein is composed of chorismate mutase (AroQ(T)) fused to the N-terminus of prephenate dehydrogenase (TyrA). Here, we report the replacement of AroQ(T) with the β1-domain of protein G (Gβ1). The TyrA domain shows a strong dehydrogenase activity within the context of this fusion, and our data indicate that Gβ1-TyrA folds into a dimeric conformation. Amino acid substitutions in the Gβ1 domain of Gβ1-TyrA identified residues involved in stabilizing the TyrA dimeric conformation. Gβ1 substitutions in the N-terminal β-hairpin eliminated Gβ1-TyrA expression, whereas Gβ1-TyrA tolerated Gβ1 substitutions in the C-terminal β-hairpin and in the α-helix. All of the characterized variants folded into a dimeric conformation. The importance of the β2-strand in forming a Gβ1 homo-dimerization interface explains the relevance of the first-β-hairpin in stabilizing the dimeric TyrA protein.
authors.affiliation: Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico. joel@ibt.unam.mx
authors.forename: Joel
authors.initials: J
authors.lastname: Osuna
authors.forename: Humberto
authors.initials: H
authors.lastname: Flores
authors.forename: Gloria
authors.initials: G
authors.lastname: Saab-Rincón
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D002826:Chorismate Mutase / Q000737:chemistry* / Q000235:genetics; D019281:Dimerization; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000235:genetics; D011303:Prephenate Dehydrogenase / Q000737:chemistry* / Q000235:genetics; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C034284:IgG Fc-binding protein, Streptococcus; D009097:Multienzyme Complexes; D011993:Recombinant Fusion Proteins; C076398:TyrA protein, Bacteria; D011303:Prephenate Dehydrogenase; D002826:Chorismate Mutase