sup 1 H NMR studies of tris(phenanthroline) metal complexes bound to oligonucleotides: Structural characterizations via selective paramagnetic relaxation

Journal Article · Tue Feb 20 04:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00459a007· OSTI ID:6976491

Rehmann, J P; Barton, J K ^[1]

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1. Columbia Univ., New York, NY (USA)

The selective paramagnetic relaxation of oligonucleotide protons of d(GTGCAC){sub 2} by {Delta}- and {Lambda}-Ni(phen){sub 3}{sup 3+} and {Delta}- and {Lambda}-Cr(phen){sub 3}{sup 3+} has been examined to obtain some structural insight into the noncovalent binding of tris(phenanthroline) metal complexes to DNA. The experiments demonstrate that the relative rate of relaxation of different oligonucleotide protons by the paramagnetic metal complex varies with the chirality of the metal complex and, to a lesser extent, the metal charge. The proton most efficiently relaxed in all cases is the adenosine AH2, which is situated in the minor groove of the oligonucleotide helix. Distances between the metal center and oligonucleotide protons were calculated on the basis of the relaxation data, and these distances were used to generate a set of models to describe the interactions of the rigid metal complex with the helix. For {Lambda}-isomers, the data are consistent with a predominant surface-bound association in the minor groove of the DNA helix. The results for {Delta}-isomers correlate better with models that incorporate also a major groove intercalative mode. Despite the absence of hydrogen-bonding groups in the metal complex, the surface-bound model of the phenanthroline complex in the minor groove of DNA resembles the noncovalent association seen with other DNA groove binding molecules.

• OSTI ID: 6976491
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:7; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
AROMATICS
AZAARENES
BARYONS
CHROMIUM COMPLEXES
COMPLEXES
DNA
ELEMENTARY PARTICLES
FERMIONS
HADRONS
HETEROCYCLIC COMPOUNDS
MAGNETIC RESONANCE
MAGNETISM
NICKEL COMPLEXES
NUCLEAR MAGNETIC RESONANCE
NUCLEIC ACIDS
NUCLEONS
OLIGONUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PARAMAGNETISM
PHENANTHROLINES
PROTONS
RELAXATION
RESONANCE
STRUCTURAL MODELS
TRANSITION ELEMENT COMPLEXES