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Clustering of nucleobases with alkali metals studied by electrospray ionization tandem mass spectrometry: implications for mechanisms of multistrand DNA stabilization
Author(s) -
Koch Kim J.,
Aggerholm Tenna,
Nanita Sergio C.,
Graham Cooks R.
Publication year - 2002
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.326
Subject(s) - chemistry , nucleobase , thymine , pentamer , uracil , electrospray ionization , guanine , tandem mass spectrometry , mass spectrometry , crystallography , dna , nucleotide , chromatography , biochemistry , gene
Self‐clustering of the five common nucleobases was investigated by electrospray ionization tandem mass spectrometry and shown to provide insight into the non‐covalent interactions between identical bases. Alkali and ammonium cations significantly increase self‐aggregation of the nucleobases and lead to the formation of uniquely stable magic number clusters. Sodium adducts of guanine, thymine and uracil preferentially take the form of tetrameric (quartet) clusters. This gas‐phase result correlates with previously reported solution‐phase data on sodium cation stabilized guanosine, thymine and uracil quartet structures believed to be responsible for telomere stabilization. In the presence of potassium, cesium or ammonium cations, pentameric magic number clusters are formed from thymine and uracil, while in solution the nucleoside isoguanosine yields clusters of this favored size. The formation of magic number metaclusters occurs for thymine and uracil in the presence of ammonium cations. These doubly charged 10‐ and 15‐mers are tentatively attributed to the formation of pentamer/ammonium cation/ pentamer sandwich structures. Copyright © 2002 John Wiley & Sons, Ltd.