The design and applications of a chiral probe for A-form nucleic acids tris(3,4,7,8-tetramethyl-1,10-phenanthroline) ruthenium (II) complex
A chiral metal complex and its interactions with various forms of nucleic acids were characterized in order to probe a specific for the A-conformation. Tris(3,4,7,8-tetramethyl-1,10-phenanthroline) ruthenium(II), Ru(TMP){sub 3}{sup 2+}, was synthesized and used to investigate both the global secondary structure and the local variations in conformation of polynucleotides. The metal complex binds cooperatively to A-form helices of various base sequences under conditions where little or no binding was found to analogous B- or Z-form DNAs. The binding is accompanied by an enantiomeric selectivity for the {Lambda}-isomer, which is favored in surface binding. Photoactivated DNA cleavage may be coupled to this conformation-specific binding by taking advantage of the photophysical properties of ruthenium(II) complexes. {Lambda}-Ru(TMP){sub 3}{sup 2+} cleaves preferentially {sup 3}H-labeled {Lambda}-form polymers upon irradiation with visible light. Comparative mapping of cleavage sites on a linear pBR322 fragments for tris(phenanthroline)ruthenium(II), which binds to B-DNA and cleaves also by sensitization of singlet oxygen, and for Ru(TMP){sub 3}{sup 2+} shows the selective bonding of {Lambda}-Ru(TMP){sub 3}{sup 2+} to conformationally distinct sites along the fragment. Ru(TMP){sub 3}{sup 2+} was applied to investigate the structures of the promoter regions of Xenopus 5S RNA gene and Simian Virus 40 DNA. Specific sites for Ru(TMP){sub 3}{sup 2+} were found in these two promoter sequences and conformational heterogeneity were thus proposed in these important control regions.
- Research Organization:
- Columbia Univ., New York, NY (USA)
- OSTI ID:
- 6940437
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
AMPHIBIANS
ANIMALS
AQUATIC ORGANISMS
BIOASSAY
BIOCHEMICAL REACTION KINETICS
CHEMICAL COMPOSITION
CLEAVAGE
COMPLEXES
CRYSTAL STRUCTURE
DNA
ELECTROMAGNETIC RADIATION
FROGS
GENES
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
KINETICS
MICROORGANISMS
MICROSTRUCTURE
MOLECULAR STRUCTURE
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PARASITES
RADIATIONS
REACTION KINETICS
RNA
RUTHENIUM COMPLEXES
SIMIAN VIRUS
TRACER TECHNIQUES
TRANSITION ELEMENT COMPLEXES
TRITIUM COMPOUNDS
VERTEBRATES
VIRUSES
VISIBLE RADIATION