title: Modulation of MutS ATP-dependent functional activities by DNA containing a cisplatin compound lesion (base damage and mismatch).
abstract: DNA damage-dependent signaling by the DNA mismatch repair (MMR) system is thought to mediate cytotoxicity of the anti-tumor drug cisplatin through molecular mechanisms that could differ from those required for normal mismatch repair. The present study investigated whether ATP-dependent biochemical properties of Escherichia coli MutS protein differ when the protein interacts with a DNA oligonucleotide containing a GT mismatch versus a unique site specifically placed cisplatin compound lesion, a cisplatin 1,2-d(GpG) intrastrand cross-link with a mispaired thymine opposite the 3' platinated guanine. MutS exhibited substantial affinity for this compound lesion in hydrolytic and in non-hydrolytic conditions of ATP, contrasting with the normal nucleotide inhibition effect of mispair binding. The cisplatin compound lesion was also shown to stimulate poorly MutS ATPase activity to approach the hydrolysis rate induced by nonspecific DNA. Moreover, MutS undergoes distinct conformation changes in the presence of the compound lesion and ATP under hydrolytic conditions as shown by limited proteolysis. In the absence of MutS, the cisplatin compound lesion was shown to induce a 39 degrees rigid bending of the DNA double helix contrasting with an unbent state for DNA containing a GT mispair. Furthermore, an unbent DNA substrate containing a monofunctional adduct mimicking a cisplatin residue failed to form a persistent nucleoprotein complex with MutS in the presence of adenine nucleotide. We propose that DNA bending could play a role in MutS biochemical modulations induced by a compound lesion and that cisplatin DNA damage signaling by the MMR system could be modulated in a direct mode.
authors.affiliation: Centre de Biophysique Moléculaire, CNRS, Rue Charles Sadron, 45071 Orléans Cedex 02, France.
authors.forename: Yuliya
authors.initials: Y
authors.lastname: Sedletska
authors.forename: Laurence
authors.initials: L
authors.lastname: Fourrier
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Malinge
mesh_terms: D000225:Adenine / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D000266:Adenylyl Imidodiphosphate / Q000494:pharmacology; D020137:Base Pair Mismatch / Q000187:drug effects*; D001483:Base Sequence; D002945:Cisplatin / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology*; D004247:DNA / Q000378:metabolism*; D018736:DNA Adducts / Q000378:metabolism; D004249:DNA Damage; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology*; D006868:Hydrolysis / Q000187:drug effects; D008969:Molecular Sequence Data; D051719:MutS DNA Mismatch-Binding Protein / Q000737:chemistry / Q000378:metabolism*; D009692:Nucleic Acid Heteroduplexes / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D011487:Protein Conformation / Q000187:drug effects; D013379:Substrate Specificity / Q000187:drug effects; D020349:Surface Plasmon Resonance; D013941:Thymine / Q000378:metabolism
chemical_list: D018736:DNA Adducts; D009692:Nucleic Acid Heteroduplexes; C032799:chlorodiethylenetriamine platinum; D000266:Adenylyl Imidodiphosphate; D000255:Adenosine Triphosphate; D004247:DNA; D051719:MutS DNA Mismatch-Binding Protein; D000225:Adenine; D002945:Cisplatin; D013941:Thymine