Читать книгу Chemistry and Biology of Non-canonical Nucleic Acids - Naoki Sugimoto - Страница 47

The conformations of nucleotides depend on the torsion angles for rotation around each bonding shown in Figure 3.3. There are seven torsion angles (α, β, γ, δ, ε, ζ, χ) per nucleotide that must be specified to characterize the conformation of ordered structures for the nucleic acids. The duplex formation is favorable for enthalpy. However, the loss of conformational entropy is induced by reduction of degrees of freedom for nucleotides.

Figure 3.3 Torsion angles in a polyribonucleotide chain.