Zakia Bayguzhina
The Number RM in DNA. Non-coding DNA
Perhaps there are still unknown sources?
An interesting feature of DNA has recently been discovered. This is “number RMˮ. How is it related to energy?
To do this, consider the scheme of the structure of DNA.
Scheme of arrangement of complementary nitrogenous bases in DNA.
You can see some numbers on the scheme. These numbers show the sum of the electrons of each nitrogenous base included in the DNA. In adenine, the total number of electrons is 69, in thymine – 65, in the other pair guanine contains 77 electrons, cytosine – 57.
Complementary pairs:
Adenine + Thymine = 69 + 65 = 134
Guanine + Cytosine = 77 + 57 = 134
The number 134 is the number RM.
The number RM is the total number of electrons in complementary pairs of nitrogenous bases in DNA and is equal to 134.
What does this number give?
Based on the data obtained, it can be concluded that equal electrostatic repulsive forces act between complementary pairs of nitrogenous bases in the DNA molecule. Therefore, the complementarity of nitrogenous bases in DNA is also determined by the total number of electrons in the planes – the number RM.
Now back to the “junkˮ DNA.
It is known that in the non-coding part of the molecule, so called CpG islands are found, as well as complementary pairs of nitrogenous bases: C -G.
CpG islands are regions of DNA where the cytosine nucleotide follows the guanine nucleotide in a linear sequence. CpG islands are often located near structural genes that contain regulatory sequences characteristic of promoters. CpG islands are present in these regions in approximately 60% of genes.
So we came to the main point. What is the unknown function of “junkˮ DNA?
This function is the formation of energy, which is released in the form of heat during the unwinding of DNA in the process of demethylation.
But first, let's recall what DNA methylation is.
DNA methylation is the addition of a methyl group (—CH₃) to cytosine from the S-adenosylmethionine acceptor and is catalyzed by an enzyme.
In this case, a stronger twisting of DNA occurs as a result of an increase in the electrostatic repulsive forces between neighboring complementary pairs of nitrogenous bases.
