The iconic double helix of DNA that James Watson and Francis Crick first published in 1953 was not the end of DNA structure as new Study revealed.The double helix of DNA was just a tiny fraction of a real genome.It consists of 12 DNA base-pairs that later formed building blocks of DNA known as helical ladder.
DNA structure is made up of almost 3 millions base-pairs that must fit into nucleus of a cell which is just 10 micrometers across, thus DNA must really have to coil to fit into nucleus.
To get the bigger picture according to the new research,the researchers recreated DNA molecules in the lab. The researchers forced DNA strands to coil and recoil it at the same for several turns using short circular snippets of DNA that is made up of many base-pairs.
The researchers the discovered a panoply of a breathtaking new shape of DNA.
Supercomputer simulations show how the dynamic motion of the supercoiled DNA causes its shape to change constantly to form a myriad of structures.
Most of which have different shape of DNA like handcuffs or sewing needles.Others through their coiling shape look like rods.
Photo credit: LIVESCIENCE/Thana Sutthibutpong
To make this ‘supercoiled’ DNA strands visible in the human body,researchers inserted an enzyme called human topoisomerase II alpha into the body to show how this ‘supercoiled’ DNA look like in the body.
The enzyme relaxed DNA twisted DNA in human body.This new discovery of ‘SUpercoiled’ DNA was reported today (oct 12) in the Journal Nature Communications posted by livescience that the structural shape of DNA created in the lab resembled the strands of DNA found in the cell nucleus.
The DNA samples were then froze and used a special form of microscopy to capture the first-ever images.
According to James Watson and Francis Crick, DNA helix is formed when complementary base-pairs like adenine and guanine are bound together which is now being contradicted by the new simulation of DNA in the new study that these base-pairs peel apart when the helix is unraveled.
The new discovered has shown us the complexity of the structure of DNA.It is now beyond double helix and it is so interesting to see how ‘supercoiled’ is DNA.
KUOL BIONG
