Nucleoside antibiotics: Conformation and biological activity

Abstract

Minor modifications in pyrimidine and purine nucleosides have a profound effect on their biological activity. These modified nucleosides which exhibit a wide variety of antiviral, antibacterial, antitumor or cancerostatic properties are collectively called as nucleoside antibiotics. Conformational properties of these antibiotics have been investigated by quantum mechanical PCILO method. The results indicate that the nucleoside antibiotics and their parent nucleosides have very similar conformational preferences and this is specially so in the situations that occur in aqueous media. This result has important biological implications; these antibiotics can easily get incorporated in growing chains of RNA or DNA by mimicking their parent nucleosides and then bring about the inhibition of RNA or DNA or protein synthesis.