sa sa 2255
Scientists have discovered a new DNA structure, which is not the double helix + Photo May 11, 2018 | 10:06 / Interesting information

In 1953, American biologist James Watson and English physicist Francis Crick published a scientific paper that revealed their discovery: the double helix structure of DNA. Now, scientists have identified another structure of DNA. In a paper published in Nature Chemistry, researchers from Australia describe the first-ever sighting of a DNA component—called the intercalated motif  (i-motif)—within living human cells. The shape of the structure has been likened to a “twisted knot”. The i-motif is a four-stranded “knot” of DNA. In the knot structure, C (cytosine) letters on the same strand of DNA bind to each other—so this is very different from a double helix, where “letters” on opposite strands recognize each other, and where Cs bind to Gs (guanines). The i-motif had been previously identified in vitro but never in living cells. I-motifs are appearing and disappearing over time, so they are forming, dissolving and forming again. I-motifs were found to appear mainly in the regions named promotor and telomere, which is probably related to their functions. Though the function of the i-motif is not clear yet, based on the obtained data, i-motif appears at the end of “the living phase of the cell”, especially in G1 phase when DNA is actively read. Therefore, the formation of these structures might be of utmost importance for the cell to function normally and any aberration in these structures might have pathological consequences.