Synthesis and spectroscopic studies of the aminoglycoside (neomycin)--perylene conjugate binding to human telomeric DNA

Biochemistry. 2011 Apr 12;50(14):2838-49. doi: 10.1021/bi1017304. Epub 2011 Mar 17.

Abstract

Synthesis of a novel perylene-neomycin conjugate (3) and the properties of its binding to human telomeric G-quadruplex DNA, 5'-d[AG3(T2AG3)3] (4), are reported. Various spectroscopic techniques were employed to characterize the binding of conjugate 3 to 4. A competition dialysis assay revealed that 3 preferentially binds to 4, in the presence of other nucleic acids, including DNA, RNA, DNA-RNA hybrids, and other higher-order structures (single strands, duplexes, triplexes, other G-quadruplexes, and the i-motif). UV thermal denaturation studies showed that thermal stabilization of 4 increases as a function of the increasing concentration of 3. The fluorescence intercalator displacement (FID) assay displayed a significantly tighter binding of 3 with 4 as compared to its parent constituents [220-fold stronger than neomycin (1) and 4.5-fold stronger than perylene diamine (2), respectively]. The binding of 3 with 4 resulted in pronounced changes in the molar ellipticity of the DNA absorption region as confirmed by circular dichroism. The UV-vis absorption studies of the binding of 3 to 4 resulted in a red shift in the spectrum of 3 as well as a marked hypochromic change in the perylene absorption region, suggesting that the ligand-quadruplex interaction involves stacking of the perylene moiety. Docking studies suggest that the perylene moiety serves as a bridge that end stacks on 4, making contacts with two thymine bases in the loop, while the two neomycin moieties branch into the grooves of 4.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Base Sequence
  • Binding Sites
  • DNA / chemistry*
  • DNA / genetics
  • DNA / metabolism
  • G-Quadruplexes
  • Humans
  • Hydrogen Bonding
  • Models, Molecular
  • Neomycin / chemistry*
  • Neomycin / metabolism
  • Nucleic Acid Denaturation
  • Perylene / chemistry*
  • Perylene / metabolism
  • Spectrophotometry / methods*
  • Telomere / genetics
  • Temperature

Substances

  • Perylene
  • DNA
  • Neomycin