Structure of Duplex Dna Containing the Cisplatin 1,2- {pt(nh3)2}[superscript 2]+-d(gpg) Crosslink at 1.77 [angstrom] Resolution Terms of Use Detailed Terms Structure of Duplex Dna Containing the Cisplatin 1,2-{pt(nh 3 ) 2 } 2+ -d(gpg) Cross- Link at 1.77 Å Resolution

The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Synopsis The structure of a cisplatin-modified DNA dodecamer duplex containing a 1,2-cis-{Pt(NH 3) 2 } 2+-d(GpG) cross-link has been determined at 1.77-Å resolution. Improved electron density reveals new features not seen in the originally published 2.6 Å structure. Abstract We report the 1.77-Å resolution X-ray crystal structure of a dodecamer DNA duplex with the sequence 5'-CCTCTGGTCTCC-3' that has been modified to contained a single engineered 1,2-cis-{Pt(NH 3) 2 } 2+-d(GpG) cross-link, the major DNA adduct of cisplatin. These data represent a significant improvement in resolution over the previously published 2.6-Å structure. The ammine ligands in this structure are clearly resolved, leading to improved geometry of the cross-link. Other new features of this model include the location of four octahedral [Mg(H 2 O) 6 ] 2+ complexes associated with bases in the DNA major groove and the identification of 124 additional ordered water molecules that participate in hydrogen bonding interactions with either the nucleic acid or the diammineplatinum(II) moiety. The global DNA geometry is overall very similar between the current and originally determined structures.