title: Some amino acids of the Pseudomonas aeruginosa MutL D(Q/M)HA(X)(2)E(X)(4)E conserved motif are essential for the in vivo function of the protein but not for the in vitro endonuclease activity.
abstract: Human and Saccharomyces cerevisiae MutLα, and some bacterial MutL proteins, possess a metal ion-dependent endonuclease activity which is important for the in vivo function of these proteins. Conserved amino acids of the C-terminal region of human PMS2, S. cerevisiae PMS1 and of some bacterial MutL proteins have been implicated in the metal-binding/endonuclease activity. However, the contribution of individual amino acids to these activities has not yet been fully elucidated. In this work we show that Pseudomonas aeruginosa MutL protein possess an in vitro metal ion-dependent endonuclease activity. In agreement with previous published results, we observed that mutation of the aspartic acid, the first histidine or the first glutamic acid of the conserved C-terminal DMHAAHERITYE region results in nonfunctional in vivo proteins. We also determined that the arginine residue is essential for the in vivo function of this protein. However, we unexpectedly observed that although the first glutamic acid mutant derivative is not functional in vivo, its in vitro endonuclease activity is even higher than that of the wild-type protein.
authors: Centro de Investigaciones en Química Biológica de Córdoba, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA, Córdoba, Argentina.
authors: Elisa M E
authors: EM
authors: Correa
authors: Mariana A
authors: MA
authors: Martina
authors: Luisina
authors: L
authors: De Tullio
authors: Carlos E
authors: CE
authors: Argaraña
authors: José L
authors: JL
authors: Barra
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017124:Conserved Sequence; D004720:Endonucleases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D011487:Protein Conformation; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000235:genetics; D016415:Sequence Alignment
chemical_list: D004720:Endonucleases