Mass spectrometric evaluation of the gas phase structure of noncovalent quadruplex DNA obtained by electrospray ionization
- Pacific Northwest Lab., Richland, WA (United States)
- Eastern Oregon State College, LaGrande, OR (United States)
A number of quanine-rich DNA sequences have been recognized which assemble into quadrupole-helical non-Watson/Crick hybridized structures. These sequences have been localized in a number of key regions in chromosomal DNA including telomers and transcriptional promoters. The preservation of this tetrameric association in the gas phase following electrospray ionization (ESI) has been reported in this laboratory. The authors have extended these studies by the preparation of four candidate quadruplex oligomers. Three of these (I, 5{prime}-dCGC GGG GCG-3{prime}; II, 5{prime}dCGC GGGG GCG-3{prime} and III, 5{prime}-dCGC GGGGG GCG-3{prime}) differ in the number of quanine residues available for G-quartet stacking in the quadruplex array and a fourth (HG, 5{prime}-dCGC AGGG GCG03{prime}) is a sequence prominent in human telomeric DNA. During their preparation, the authors observed remarkable stability of the multimeric species in the condensed phase including intact migration in HPLC under apparently {open_quotes}denaturing{close_quotes} conditions. Under standard conditions (aqueous solution of oligonucleotide samples and nozzle-skimmer interface) on a linear quadrupole mass spectrometer oligonucleotide samples showed the typical distribution of charge states for unassociated oligonucleotides. ESI from phosphate-EDTA buffered solutions with the utilization of a capillary/skimmer interface arrangement which provides mild conditions for transfer of ions through the atmosphere/vacuum interface afforded spectra which show prominent contributions from species with quadrupole stoichiometry together monomeric materials.
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 61958
- Report Number(s):
- CONF-9405234-; TRN: 95:003327-0093
- Resource Relation:
- Conference: 42. American Society of Mass Spectrometry (ASMS) conference on mass spectrometry and allied topics, Chicago, IL (United States), 29 May - 3 Jun 1994; Other Information: PBD: 1994; Related Information: Is Part Of Proceedings of the 42nd ASMS conference on mass spectrometry and allied topics; PB: 1233 p.
- Country of Publication:
- United States
- Language:
- English
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