China
Africa
Explore chapters and articles related to this topic
UV Light Microbial Inactivation in Foods
Published in Tatiana Koutchma, Ultraviolet Light in Food Technology, 2019
DNA and RNA are long polymers composed of combinations of four nucleotides. In DNA, the nucleotides are the purines, adenine and guanine, and the pyrimidines, thymine and cytosine. In RNA, the nucleotides are the purines, adenine and guanine, and the pyrimidines, uracil and cytosine. The nucleic acid is double-stranded; nucleotides on one strand will complement those on the other strand. Adenine pairs with thymine in DNA and uracil in RNA while guanine pairs with cytosine. Hydrogen bonds form between each pair. Each nucleotide can be broken into two parts – a sugar-phosphate and a nitrogenous base (Figure 4.1).
+
Published in Jean-Louis Burgot, Thermodynamics in Bioenergetics, 2019
ATPH4 is comprised of several kinds of building blocks. A first block has the structure of adenine which is a derivative of the aromatic nucleus named purine. Adenine is the 6-amino purine (Figure 58). Structure of adenosine triphosphoric acid ATPH4.Structures of adenine and adenosine.
Comparison of the stability of thymine tautomers and the interaction of its tautomers with Na+, K+, Mg2+ and Ca2+ in gas and solvent phases
Published in Molecular Physics, 2020
Marzyeh Mohammadi, Shapour Ramazani
In DNA, thymine binds to adenine via two hydrogen bonds, hence stabilising the nucleic acid structures, while in RNA, adenine binds to uracil. Under the influence of ultraviolet light, the normal structure of DNA is interrupted and unintentional mutations occur in the pairing of thymine with other bases and other thymine molecules. Metalation of thymine can cause inconformity in the base pairing. Metal cations can stabilise the rare nucleobase tautomers and increase the probability of gene mutations [9–11]. The present authors also considered the tautomerism of thymine [12], where 18 structures were reported (T1–T18). Further investigated were three types of interaction between sodium ion and tautomers. In that article, the stability rate of thymine tautomers and their complexes were determined, and it was shown that thymine is much more stable than other tautomers. Stability was caused by the interaction of metal cations with tautomers in all complexes and was more tangible for tautomers than for thymine.