Stylonychia lemnae

The natural occurrence of G-quadmplex in human telomeric sequences remains unproven, although a recent report provides convincing evidence of their occurrence in Stylonychia lemnae telomeres (80). Nevertheless, the existence of... 

C. Schaffitzel, I. Berger, J. Postberg, J. Hanes, H.J. Lipps and A. Pluckt-hun, In vitro generated antibodies specific for telomeric guanine-quadru-plex DNA react with Stylonychia lemnae macronuclei, Proc. Natl. Acad. Sci. USA, 2001, 98, 8572-8577. 

Quadruplexes can be uni-, bi- or tetramolecular. Since under physiological conditions the strand concentration of DNA is relatively low (order nM), except in rare exceptions such as Stylonychia lemnae macronuclei,interstrand quadruplexes will be strongly disfavoured. Therefore, only sequences that can from intramolecular quadruplexes were considered. 

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