Energetics of echinomycin binding to DNA
AUTOR(ES)
Leng, Fenfei
FONTE
Oxford University Press
RESUMO
Differential scanning calorimetry and UV thermal denaturation have been used to determine a complete thermodynamic profile for the bis-intercalative interaction of the peptide antibiotic echinomycin with DNA. The new calorimetric data are consistent with all previously published binding data, and afford the most rigorous and direct determination of the binding enthalpy possible. For the association of echinomycin with DNA, we found ΔG° = –7.6 kcal mol–1, ΔH = +3.8 kcal mol–1 and ΔS = +38.9 cal mol–1 K–1 at 20°C. The binding reaction is clearly entropically driven, a hallmark of a process that is predominantly stabilized by hydrophobic interactions, though a deeper analysis of the free energy contributions suggests that direct molecular recognition between echinomycin and DNA, mediated by hydrogen bonding and van der Waals contacts, also plays an important role in stabilizing the complex.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=275468Documentos Relacionados
- Echinomycin binding to alternating AT.
- Hoogsteen base pairs proximal and distal to echinomycin binding sites on DNA.
- Sequence-specific binding of echinomycin to DNA: evidence for conformational changes affecting flanking sequences.
- Unstable Hoogsteen base pairs adjacent to echinomycin binding sites within a DNA duplex.
- Kinetic evidence that echinomycin migrates between potential DNA binding sites.