Johann Friedrich Miescher was the first one to introduce us about his finding of an acidic substance which was weak in nature and was present in the nuclei of the WBC present in human beings and the first name given to this substance was “nuclien”. It took few more years for Miescher to research and find out the two components present in the unknown substance and they were “protein” and “nucleic acid”.
As the research on the nucleic acid progressed, it was found that they were the primary components present in chromosomes and a close analysis of the constituents revealed that there is a presence of phosphorus along with Carbon, Hydrogen, Nitrogen and Oxygen but no sulphur. Now a complete hydrolysis of the nucleic acid found in chromosomes was done and the result was in the form of an inorganic phosphate which was 2-Deoxyribose and different types of four heterocyclic bases. (Please refer to the figure on the next page for structure). After this research the naming was done as Deoxyribonucleic Acid (DNA for the chromosomal nucleic acids) with unusual sugar component and ribonucleic acid (RNA for the analogous acids).
Let’s now discuss about the differentiation and the naming done to the components present in the nucleic acid; pyrimidines are the two monocyclic bases and a couple of bicyclic bases present are called as the purines. All the above have N-H structure present which may have an organic substituent attached to it and because of this all of them are polyfunctional bases and there is a possibility that these exist in the form of tautometric form. The DNA and RNA can also be further characterized on the basis of Base-catalyzed hydrolysis, on one hand where the DNA is basically N-glycosides of 2′-deoxyribose and further includes heterocyclic amines, on the other hand the RNA basically have the N-glycosides named to be cytidine, adenosine, uridine and guanosine. Based on the discussion above it can be deduced that the nucleic acids can be inferred to be the copolymers of Nucleosides and Phosphorus (N&P).
Nature of DNA
As we know that the DNA has a structure which is polymeric but actually its description is given through the monomeric units with increasing complexity. The important points to understand from this structure is that post the selective hydrolysis P-OH remains and is very acidic thus getting completely ionized, secondly the polymer chain works in a structural direction and therefore composition is different at different ends, thirdly despite having the structure of a simple polymer the permutations cause the chain to become very lengthy at times and lastly the size of the DNA polymer is too large as initially believed and is mostly 109 or above. The DNA stores information which gets encoded using the pattern in a manner where there is an arrangement of four nucleotides. It is also said that the DNA is like an informational library providing immediate access to information required by the body machinery.
Nature of RNA
RNA has a lower molecular weight as compared but is presence is more. It is well distributed throughout the cells in the shape of minute organelles which are known as Ribosomes. The RNAs are primarily of three types namely Ribosomal, messenger and transfer. These basically play a very important role in the transfer of information and the interpretation of the same which is used for the synthesis as well.
Blackburn, Michael and Royal Society of Chemistry (Great Britain). Nucleic acids in chemistry and biology. London: RSC Publishing, 2006. medterms.com.
Nucleotides and Nucleic Acids. 1 Feburary 2011 <http://www.chem.ucla.edu/harding/notes/notes_14C_nucacids.pdf>.
Westheimer, F. H. Nucleic Acids. 6 March 1987. 2 Feburary 2011 <http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/nucacids.htm>.