Kitabı oku: «DNA Reveals Its Secret», sayfa 3
In thymine (C5H6N2O2 – 66) the total number of electrons in DNA is 65, in the complementary adenine base (C5H5N5 – 70) – 69, in cytosine (C4H5N3O – 58) in the DNA molecule – 57, in guanine (C5H5N5O – 78) in DNA – 77.
Complementary pairs:
adenine + thymine = 69 + 65 = 134
guanine + cytosine = 77 + 57 = 134
The number 134 is the RM number.
Thus, the complementarity of nitrogenous bases in DNA is also determined by the total number of electrons in the planes – the RM number.
This is the secret of DNA, the very key with which we can lift the heavy veil of mystery that surrounds this molecule…
This key also reveals its other secrets. The great Pythagoras said: "Numbers rule the world." And in this case, he was right.
It can be assumed that uracil may have been present in DNA at the early stages of evolution, but later it was methylated, resulting in the formation of thymine. Uracil makes DNA unstable. As we remember, the number RM is 134. The number of electrons of uracil (С4H4N2O2 – 58) is 57 in a molecule, in total with adenine in DNA it is 126. The absence of eight electrons would lead to destabilization of the molecule. The instability of the polymer would increase the number of cells, which was necessary at the dawn of living beings.
The total charge of electrons forms a single field at the complementary bases, which, being in a stack, act repulsively against each other, forcing the base pairs to release the voltage force by rotating the planes about the axis. Thus, a spirally twisted double chain is formed. This DNA construction – the replacement of uracil with thymine – creates stability between complementary bases and determines the stability of the molecule.
B-form DNA parameters.
This form is found in a living cell. There are approximately ten pairs of complementary bases per turn of DNA, the distance between them is 0.34 nm. The angle of rotation between adjacent base pairs, respectively, is 36 degrees, the helix width is 2.0 nm. We will focus on this data, since accuracy is not so important in our calculations. First of all we want to show how the force F acting between the layers changes.
Let's calculate the distance between adjacent complementary nitrogenous bases in an unfolded molecule – if one plane is under the other.
DNA scheme with located complementary nitrogenous bases.
BG, HJ – parallel DNA planes, presented as straight lines, helix diameter (DNA width).
HJ = CE.
DC is the distance between parallel complementary nitrogenous bases in an unfolded DNA molecule. The BAC angle of 36 degrees is the angle of rotation between adjacent base pairs. BAF angle = 36: 2 = 18. ∆BAC is an isosceles triangle; therefore, AF is both a bisector and a median:
BF = FC = Sin <BAF x VA
BG equal to 2.0 nm – helix diameter (DNA width)
BA = 2.0: 2 = 1.0 nm
Point A is the center of the DNA axis
Sin <BAF = 0.309 (according to the table)
BF = 0.309 x 1.0nm = 0.309nm
BC = 0.309nm x 2 = 0.618nm
BD – distance between bases equal to 0.34 nm
DC = √BC2 + BD2 = √0.6182 + 0.342 = √0.381924 + 0.1156 = √0.497524 = 0.7053538 nm.
0.7053538 nm, or 0.705 nm, is the distance between the planes of complementary pairs if the DNA were in the unfolded state, i.e. when adjacent parallel layers were under each other.
Consider the action of the RM number.
As we found out, the distance between the planes is 0.705 nm. The electrons of the complementary nitrogenous bases create electronic fields around the base planes. As we know, the same charges repel each other. The force (F) acting on parallel planes can be represented by Coulomb's law, the total number of electrons in complementary pairs is 134.
