Specific Metal-Oligonucleotide Binding Studied by High Resolution Tandem Mass Spectrometry

✍ Scribed by Wu, Qinyuan; Cheng, Xueheng; Hofstadler, Steven A.; Smith, Richard D.

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 687 KB
• Volume: 31
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/(sici)1096-9888(199606)31:6<669::aid-jms340>3.0.co;2-5

✦ Synopsis

Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) was used to study the binding of metal ions to two oligonucleotides, d(pGCTTGCATp) and d(TTGGCCCTCCTT). Collision-induced dissociation (CID) of the metahligonucleotide complex revealed that metal ions preferentially bound to the central thymine region of the sequence. The most probable binding sites were the phosphodiester backbone since the sum of the maximum number of charge addition from the metal ions and the charge state of the whole complex was found to be equal to the number of ionizable protons on the DNA backbone. Although sitespecific and sequence-specific binding was observed for all three of the metal ions studied, the binding specificity of UO;' ions was significantly greater than €or Mg2+ and Na+. These experiments demonstrate that ESI-MS/MS can be applied to study the binding of metal ions and their complexes to oligonucleotides, providing not only information on the number of metal ions binding to the oligonucleotide, but also information related to the binding site(s) and binding specificity.