The discovery of the double-helix DNA by Watson and Crick in 1953 brought them the Nobel Prize in Physiology and Medicine. Since then, several types of DNA structures have been discovered that all form under the certain conditions.
Now, seven days ago (April 23, 2018), Garvan Institute of Medical Researchers announced that they were able to confirm the presence of another kind of DNA in human cells as the known intercalated motif, i-motif.
(Zeraati et al., Nat Chem, 2018)
The i-motif, “twisted knot”, can form in Cytosine rich sequences such as Centromeres, Telomeres, and promotor regions. In this structure the C letters on the same strand paired with each other. So this is different from a double helix, where Cytosines bind to Guanosines.
The researchers of the new study speculated that i-motif formation can switch On or Off genes. And, any aberration in these structures might have pathological consequences.
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