The Institut Laue-Langevin (ILL) scientists have calculated the speed of sound in DNA to ascertain its firmness. These discoveries help researchers to illustrate how DNA coils, folds and denatures.
Researchers at the ILL have utilized neutron scattering to find out DNA’s structural elasticity and elucidate the values acquired from earlier measurements. These research findings, recorded in Physical Review Letters, describe how DNA can fold and split to set up traits in all existing organisms and transmit these traits from one generation to the other.
DNA’s double helix structure is steadily being bent, coiled and stretched within the cell. DNA responds to this pressure according to its basic structural characteristics in order two of its basic biological functions. The first function is replication. This process shows how DNA produces copies of itself for transmitting traits from one generation to the other. The second function is transcription. Through this process genetic data is copied from DNA to RNA and this is the first move towards gene expression.
Measuring DNA elasticity in artificial solutions that strive to simulate conditions within a cell has been realized before and has produced results that signify a flexible DNA structure. But these findings differ by an order of dimension, between 0.3 to 3 N/m. The ILL team utilized neutron scattering to calculate the structural elasticity of the molecule and confirmed a force constant of 83 N/m which is coherent with the stiffer sound velocity determination. This value is approximately equal to that of nylon normally used in textiles.
The ILL researchers made these recent measurements on a ‘wet-spun’ collection of DNA, coiled onto a bobbin. The ‘wet-spun’ samples of DNA were then fixed in a new IN5 neutron scattering spectrometer of the Institute. By placing the DNA within the instrument, the team calculated the frequency of sound waves moving along the double helix structure replaced with their wavelength. Mark Johnson and his team also used computer models of DNA stretching to understand previously reported values.
Source: http://www.ill.fr/