Nucleic Acid Stability in Acidic and Basic Solutions

Nucleic acids are one of the big macromolecules that can be found in all cells, including viruses. Its purpose is to store genetic information and express it. Nucleotides are the monomers of nucleic acid that combine to form a nucleic acid. Nucleic acids are divided into two categories. The following are some examples of nucleic acids:

• DNA stands for deoxyribonucleic acid.
• RNA stands for ribonucleic acid.

DNA stands for deoxyribonucleic acid, which contains the genetic information for each person. Ribonucleic acid, or RNA, is a type of nucleic acid that aids in protein production and a variety of other cellular functions.

Nucleic acid varieties

In some species, nucleic acids such as DNA and RNA can be employed as genetic material.

DNA

All living species, including prokaryotes and eukaryotes, contain deoxyribonucleic acid (DNA). It is the repository for all creatures’ genetic information. It is the sole way for parents to pass on their traits to their children. Scientists James Watson and Francis Crick were the first to discover its structure.

Purines, such as guanine and adenine, and pyrimidines, such as thymine and cytosine, are the two forms of nitrogenous bases involved in this. Both strands of DNA are antiparallel to one another.

RNA

When compared to DNA, RNA is single-stranded. Friedrich Meischer discovered it in 1869. It has a sugar-phosphate backbone, just like DNA. It’s also a nucleotide polymer that contains a pentose sugar called ribose sugar, as well as a base and phosphate group. The nucleotides are held together by covalent bonds.

RNA can be divided into three categories:

• mRNA is essential for protein synthesis since it contains all of the information or message needed for translation.
• ribosomal RNA (rRNA) is an essential component of the ribosome.
• Transfer RNA is referred to as tRNA. It is in charge of the amino acid transfer during translation.

The process of transcription produces RNA, which is generated with the help of DNA strands.

Stability of nucleic acid in acidic and basic solutions

Nucleic acids are acidic because of the presence of phosphate groups. Nucleic acids are acidic because they contain a proton that is easily lost. In other terms, nucleic acids are made up of nucleotides due to the acidic phosphate group obtained from phosphoric acid.

Due to contaminating nucleases and inherent chemical instability, nucleic acids are found not to be structurally stable in an aqueous solution at room temperatures standing for a long period of time. The advancement of nucleic acid-based nanotechnology is hampered by this instability.

DNA is sensitive to alkaline denaturation at pH 9 or higher because there are hydroxide ions present These negatively charged ions denature DNA strands by disrupting hydrogen bonds between them.

The stability of the DNA is majorly governed by two factors namely, the two strands double helix along with the presence of  base pairing among complementary strands as well as the stacking present in between neighbouring nucleotides. It can be estimated by examining the temperature along with the salt dependency of the stacking free energy of the double helical DNA molecule with the solitary nicks and gaps.

Non-physiological temperatures, pH, and ionic strength break the DNA helix and cause conformational changes, even though DNA is relatively stable in aqueous solution.

DNA molecules are quite stable in a neutral pH range of 5 to 9. DNA molecules are susceptible to instability if the pH is too acidic or alkaline. DNA is susceptible to depurination at pH 5 or lower i.e. the loss of purine bases from DNA.

G-quartets are produced by nucleic acids with G-rich motifs and are stabilised by Hoogsteen base pairs under particular circumstances. Nucleic acids naturally create secondary or higher-order structures such as duplexes, triplexes, and G-quadruplexes due to particular interactions among the bases.

Unlike RNA, each sugar group in DNA lacks a hydroxyl group at the 2′ position. Because of this difference, DNA is substantially more stable in an alkaline solution.

Acidic pH stabilises crucial intramolecular and intermolecular RNA bonds, including those important for protein synthesis evolution, and promotes extra protonated base interactions, allowing RNA to behave under these settings without being bound by traditional base-pairing constraints.

Conclusion

Nucleic acids are found in all cells, even in viruses also. These can be of two types namely DNA and RNA. Both of these are genetic materials on organisms depending upon their nature. The presence of phosphate groups in nucleic acids makes them acidic. Because they include a proton that is quickly lost, nucleic acids are acidic. In other words, because of the acidic phosphate group derived from phosphoric acid, nucleic acids are made up of nucleotides.

The DNA helix is kept stable by Van der Waals forces, hydrogen bonding between complementary organic bases (a base pair), and hydrophobic interactions between nitrogenous bases and the surrounding sheath of water. DNA molecules are extremely stable in the pH range of 5 to 9. DNA molecules become unstable when the pH is too acidic or alkaline.

Acidic pH stabilises critical intramolecular and intermolecular RNA bonds, including those required for protein synthesis evolution, and encourages additional protonated base interactions, allowing RNA to behave under these conditions without being constrained by typical base-pairing limitations.