title: The C-terminal region of Escherichia coli MutS and protein oligomerization.
abstract: Escherichia coli MutS, an 853 amino acids oligomeric protein, is involved in the postreplicative DNA mismatch repair and avoidance of homeologous recombination. By constructing MutS mutated versions of the C-terminal region, we determined that deletion of the last 7 C-terminal amino acids is enough to abolish tetramer formation and that the K850A substitution destabilize the tetramer structure. It is proposed that the C-terminal extreme alpha helix (residues 839-850) of the protein may play an important role in protein oligomerization. We also show that the C-terminal region or the C-terminal plus the HTH domain of MutS, fused to the monomeric Maltose Binding Protein promote oligomerization of the chimeric protein. However, chemical cross-linking experiments indicate that the HTH domain improves the oligomerization properties of the fused protein. Escherichia coli cells expressing the fused proteins become hypermutator suggesting that the C-terminal region of MutS plays an important role in vivo.
authors.affiliation: Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina.
authors.forename: Virginia
authors.initials: V
authors.lastname: Miguel
authors.forename: Roberto J
authors.initials: RJ
authors.lastname: Pezza
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Argaraña
mesh_terms: D019281:Dimerization; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000648:ultrastructure*; D046912:Multiprotein Complexes / Q000737:chemistry / Q000648:ultrastructure; D051719:MutS DNA Mismatch-Binding Protein / Q000737:chemistry* / Q000648:ultrastructure*; D013329:Structure-Activity Relationship
chemical_list: D029968:Escherichia coli Proteins; D046912:Multiprotein Complexes; D051719:MutS DNA Mismatch-Binding Protein; C497175:MutS protein, E coli