In this article we will discuss about the X-ray crystallographic studies of DNA. In 1920, the basic chemical composition of nucleic acid was elucidated through the efforts of P.A. Levene. In 1940, for the first time W.T. Astbury gave first three dimensional structure of DNA model studied through X-ray crystallography. He concluded that its flat nucleotides get stacked to form [...]
In addition to organization of DNA in prokaryotes and lower eukaryotes, in eukaryotes the DNA helix is highly organised into the well-defined DNA-protein complex termed as nucleosomes. Among the proteins the most prominent are the histones. The histones are small and basic proteins rich in amino acids such as lysine and/or arginine. Almost in all eukaryotic cells there are five [...]
Nucleic acids (DNA and RNA) act as genetic material in all organisms and viruses: 1. Evidences from Bacteria 2. Evidence from Bacteriophages 3. Evidence from Bacterial Conjugation 4. Evidence from RNA Viruses. 1. Evidences from Bacteria: For the first time, an English Health officer, Frederick Griffith (1928) gave an experimental evidence that the DNA was the genetic material. He took [...]