Vanadate inhibits the ATPase activity and DNA binding capability of bacterial MutS. A structural model for the vanadate-MutS interaction at the Walker A motif.
MutS, a member of the ABC ATPases superfamily, is a mismatch DNA-binding protein constituent of the DNA post-replicative mismatch repair system (MMRS). In this work, it is shown that the ATPase activity of Pseudomonas aeruginosa and Escherichia coli MutS is inhibited by ortho- and decavanadate. Structural comparison of the region involved in the ATP binding of E.coli MutS with the corresponding region of other ABC ATPases inhibited by vanadate, including the myosin- orthovanadate-Mg complex, showed that they are highly similar. From these results it is proposed that the orthovanadate inhibition of MutS ATPase can take place by a similar mechanism to that described for other ATPases. Docking of decavanadate on the ATP-binding region of MutS showed that the energetically more favorable interaction of this compound would take place with the complex MutS- ADP-Mg, suggesting that the inhibitory effect could be produced by a steric impediment of the protein ATP/ADP exchange. Besides the effect observed on the ATPase activity, vanadate also affects the DNA-binding capability of the protein, and partially inhibits the oligomerization of MutS and the temperature-induced inactivation of the protein. From the results obtained, and considering that vanadate is an intracellular trace component, this compound could be considered as a new modulator of the MMRS.
Pezza
Roberto J
RJ
Centro de Investigaciones en Química Biológica de Córdoba, UNC-CONICET, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina.
Villarreal
Marcos A
MA
Montich
Guillermo G
GG
Argaraña
Carlos E
CE
D000244:Adenosine Diphosphate / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D051719:MutS DNA Mismatch-Binding Protein; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D011550:Pseudomonas aeruginosa / Q000201:enzymology; D012542:Scattering, Radiation; D013696:Temperature; D014638:Vanadates / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D008024:Ligands; D009838:Oligodeoxyribonucleotides; D014638:Vanadates; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D004247:DNA; D000251:Adenosine Triphosphatases; D051719:MutS DNA Mismatch-Binding Protein; C497175:MutS protein, E coli