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The selective coupling of nitrogen base pairs discovered in 1953 and indicated as a phenomenon underlying the transmission of the genetic code does not exclude DNA but occurs spontaneously even among simple nitrogen bases and so might not be the very cause of the DNA. ] the origin of the formation of DNA . This is demonstrated by a recently published study on PNAS by the University Research Group of Milan coordinated by Prof. Tommaso Bellini of BIOMETRA Department and Research Group of the University of Colorado coordinated by Prof. Noel Clark
The Watson-Crick pairing, for which the nitrogenous bases which are the basic constituents of nucleic acids such as DNA and RNA, bind selectively is at the root of not only genetic code transmission, but countless diagnostic and therapeutic methods, biotechnologies and nanotechnologies, and our understanding of the living world and its evolution.
Until now, it was thought that this was a property of the DNA strands, in which the nitrogenous bases are chemically concatenated, but the study shows that this does not occur. is not the case: Watson-Crick pairing is a property of individual nitrogenous bases. This discovery further reinforces a hypothesis about the origin of life that the Bellini-Clark collaboration has been testing for a decade: if stacking nitrate base pairs forms spontaneously, and therefore is not Effect of their chemical bond,
One of the main mysteries around the origin of life is the formation of the first biopolymers, which seem to require a selectivity that can not be attributed to training random chemical bonds. The spontaneous formation of columns of chemically independent base pairs, in which these small molecules are held together by physical forces, may have favored and guided the formation of chemical bonds that transformed these columns into true double strands of DNA or of the RNA, the first to appear on our planet
The study authors observed, by polarized microscopy and by X-ray diffraction, that they dissolve in the &,, [[[[[[[[[[[[[[[[[[[[[[waterfromsimplenitrogenbaseswithtriphosphatetermination(ATPTTPCTPGTP)theyareself-badembledinbase-paircolumnsbutonlyiftheWatson-CrickselectiveruleisrespectedForexampleATPsolutionsormixturesofTTPandCTPremaindisorderedbutmixturesofATPandTTPformveryflexiblestructuresoftheclbadofliquidcrystalsinwhichtheyarestackedtogetherATP-TTPpairs
A mixture of ATP and TTP in which one of the two components is more concentrated than the other, the system splits spontaneously, by means of a phase transition, to expel the excess part.
In the study they participated, in the guided team of prof. Bellini: Tommaso Fraccia, researcher in applied physics at San Raffaele Telematics University, Marco Todisco, PhD student in biology at the State University, Giuliano Zanchetta, researcher in applied physics from the University of San Raffaele State University
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