Phosphorus-31 NMR spectra of ethidium, quinacrine, and daunomycin complexes with poly(adenylic acid)ter dot poly(uridylic acid) RNA duplex and calf thymus DNA

Journal Article · Tue Apr 04 04:00:00 EDT 1989 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00433a010· OSTI ID:5545542

Gorenstein, D G; Lai, K ^[1]

---

1. Purdue Univ., West Lafayette, IN (USA)

{sup 31}P NMR provides a convenient monitor of the phosphate ester backbone conformational changes upon binding of the intercalating drugs ethidium, quinacrine, and daunomycin to sonicated poly(A){center dot}poly(U) and calf thymus DNA. {sup 31}P chemical shifts can also be used to assess differences in the duplex unwinding angles in the presence of the drug. Thus a new {sup 31}P signal, 1.8-2.2 ppm downfield from the double-stranded helix signals, is observed in the ethidium ion-poly(A){center dot}poly(U) complex. This signal arises from phosphates which are in perturbed environments due to intercalation of the drug. This is in keeping with the hypothesis that the P-O ester torsional angle in phosphates linking the intercalated base pairs is more trans-like. Similar though smaller deshielding of the {sup 31}P signals is observed in sonicated poly(A){center dot}poly(U)-quinacrine complexes as well as in the daunomycin complexes. The effect of added ethidium ion, quinacrine, and daunomycin on the {sup 31}P spectra of sonicated calf thymus DNA is consistent with Wilson and Jones' (1982) earlier study. In these drug-DNA complexes the drug produces a gradual downfield shift in the DNA {sup 31}P signal without the appearance of a separate downfield peak. These differences are attributed to differences in the rate of chemical exchange of the drug between free and bound duplex states. The previous correlation of {sup 31}P chemical shift with drug duplex unwinding angle is confirmed for both the RNA and DNA duplexes.

• OSTI ID: 5545542
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 28:7; 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
ANIMALS
BODY
CALVES
CATTLE
CHEMICAL BONDS
CHEMICAL REACTIONS
CHEMICAL SHIFT
CLATHRATES
CONFORMATIONAL CHANGES
CROSS-LINKING
DNA
DOMESTIC ANIMALS
ISOTOPES
LIGHT NUCLEI
LYMPHATIC SYSTEM
MAGNETIC RESONANCE
MAMMALS
MOLECULAR STRUCTURE
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUCLEIC ACIDS
ODD-EVEN NUCLEI
OLIGONUCLEOTIDES
ORGANIC COMPOUNDS
ORGANS
PHOSPHORUS 31
PHOSPHORUS ISOTOPES
POLYMERIZATION
RESONANCE
RNA
RUMINANTS
SPECTRA
STABLE ISOTOPES
THYMUS
VERTEBRATES