(g-quartets) G-quadruplexes are multi-stranded structures held together by square planes of four guanines ('G-quartets') interacting by forming Hoogsteen hydrogen bonds. G-quartet structures has been developed as novel anti-HIV agents. Several critical structure-activity relationships between HIV-1 integrase and G-quartet oligonucleotides have been demonstrated.

Higher-order DNA and RNA structures formed from guanine-rich sequences. They are formed around a core of at least 2 stacked tetrads of hydrogen-bonded GUANINE bases. They can be formed from one two or four separate strands of DNA (or RNA) and can display a wide variety of topologies, which are a consequence of various combinations of strand direction, length, and sequence. (From Nucleic Acids Res. 2006;34(19):5402-15)