In addition to the familiar duplex DNA, certain G-rich DNA sequences can fold into a variety of four-stranded structures, which are called G-quadruplexes.

CpG ODN plays its anti-HSV role not by the direct suppression of the virus-infected cells but through the stimulation of immune system.

The high-level requirements of guanine nucleotides and high GTP usage in photoreceptor cells may explain the nature of the retinal degeneration.

Mercaptopurine has been a standard component of long-term continuing treatment for childhood lymphoblastic leukaemia, whereas 6-thioguanine has been mainly used for intensification courses.

It plays an important role in maintaining the intracellular balance of A and G nucleotides.