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The term intrinsic DNA fluorescence refers to the fluorescence emitted directly by DNA when it absorbs ultraviolet (UV) radiation. It contrasts to that stemming from fluorescent labels that are either simply bound to DNA or covalently attached to it, [1] [2] widely used in biological applications; such labels may be chemically modified, not naturally occurring, nucleobases.
From the very early stages of structural studies of DNA by X-ray diffraction and biochemical means, molecular models such as the Watson-Crick nucleic acid double helix model were successfully employed to solve the 'puzzle' of DNA structure, and also find how the latter relates to its key functions in living cells.
This method is one of the most widespread [6] [7] methods for isolating nucleic acids from biological samples and is known as a simple, rapid, and reliable [2] method for the small-scale purification of nucleic acid from biological sample. This method is said to have been developed and invented by Willem R. Boom et al. around 1990.
Deoxyribonucleic acid (DNA) is a nucleic acid containing the genetic instructions used in the development and functioning of all known living organisms. The chemical DNA was discovered in 1869, but its role in genetic inheritance was not demonstrated until 1943. The DNA segments that carry this genetic information are called genes.
Contamination by phenol, which is commonly used in nucleic acid purification, can significantly throw off quantification estimates. Phenol absorbs with a peak at 270 nm and a A 260/280 of 1.2. Nucleic acid preparations uncontaminated by phenol should have a A 260/280 of around 2. [2]
CryoEM of nucleic acid has been done on ribosomes, [7] viral RNA, [8] and single-stranded RNA structures within viruses. [9] [10] These studies have resolved structural features at different resolutions from the nucleobase level (2-3 angstroms) up to tertiary structure motifs (greater than a nanometer).
The primary amine on the aminoallyl nucleotide reacts with amino-reactive dyes [9] such as a cyanine and patented dyes [10] [11] which contain a reactive leaving group, such as a succinimidyl ester .The amine groups directly attached to the ring of the base are not affected. These nucleotides are used for labeling DNA. [4] [6] [10] [11] [12]
The nucleic acid notation currently in use was first formalized by the International Union of Pure and Applied Chemistry (IUPAC) in 1970. [1] This universally accepted notation uses the Roman characters G, C, A, and T, to represent the four nucleotides commonly found in deoxyribonucleic acids (DNA).