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Non‐covalent complexes between DNA‐binding drugs and double‐stranded deoxyoligonucleotides: a study by ionspray mass spectrometry
Author(s) -
Triolo Antonio,
Arcamone Federico M.,
Raffaelli Andrea,
Salvadori Piero
Publication year - 1997
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/(sici)1096-9888(199711)32:11<1186::aid-jms575>3.0.co;2-g
Subject(s) - chemistry , dna , duplex (building) , mass spectrometry , covalent bond , intercalation (chemistry) , ligand (biochemistry) , combinatorial chemistry , competitive binding , stereochemistry , chromatography , organic chemistry , biochemistry , receptor
The non‐covalent complexes between some DNA‐binding drugs and duplex oligodeoxynucleotides were studied by ionspray mass spectrometry, with the aim of evaluating the suitability of this technique to screen rapidly a series of drugs exerting their activity through non‐covalent binding to specific base sequences of DNA. Two classes of drugs were considered, distamycins (which show affinity for the minor groove of DNA) and anthracyclines (which interact through intercalation between bases). For the former, d(CGCGAATTCGCG) 2 was chosen as the model oligodeoxynucleotide. Following optimization of sample preparation and instrumental conditions, the complexes of different distamycins were observed; depending on the ligand considered, 1:1 or 2:1 complexes were formed preferentially. A semi‐quantitative evaluation of the relative affinities was made by measuring the ratio of the complexes signals to those of the duplex, and also by competitive binding with equimolar amounts of distamycin. For anthracyclines, the daunorubicin–d(CGATCG) 2 complex was chosen as the model for a preliminary mass spectrometric study; however, the signals of the duplex and the complex were very low compared with the monomer signal. Since the complex was known to be stable in solution, this was ascribed to gas‐phase instability, probably caused by electrostatic repulsion between negatively charged phosphate groups. © 1997 John Wiley & Sons, Ltd.