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  2. Nucleosome - Wikipedia

    en.wikipedia.org/wiki/Nucleosome

    Nucleosome core particles are observed when chromatin in interphase is treated to cause the chromatin to unfold partially. The resulting image, via an electron microscope, is "beads on a string". The string is the DNA, while each bead in the nucleosome is a core particle. The nucleosome core particle is composed of DNA and histone proteins. [29]

  3. Nucleic acid quaternary structure - Wikipedia

    en.wikipedia.org/wiki/Nucleic_acid_quaternary...

    DNA quaternary structure is used to refer to the binding of DNA to histones to form nucleosomes, and then their organisation into higher-order chromatin fibres. [2] The quaternary structure of DNA strongly affects how accessible the DNA sequence is to the transcription machinery for expression of genes. DNA quaternary structure varies over time ...

  4. Nuclear organization - Wikipedia

    en.wikipedia.org/wiki/Nuclear_Organization

    Histones: DNA is wrapped around histones to form nucleosomes, which are basic units of chromatin structure. Each nucleosome consists of 8 histone protein subunits, around which roughly 147 DNA base pairs are wrapped in 1.67 left-handed turns. Nucleosomes provide about 7-fold initial linear compaction of DNA. [15]

  5. Solenoid (DNA) - Wikipedia

    en.wikipedia.org/wiki/Solenoid_(DNA)

    Histone H1 protein binds to the site where DNA enters and exits the nucleosome, wrapping 147 base pairs around the histone core and stabilising the nucleosome, [3] this structure is a chromatosome. [4] In the solenoid structure, the nucleosomes fold up and are stacked, forming a helix.

  6. Nucleic acid tertiary structure - Wikipedia

    en.wikipedia.org/wiki/Nucleic_acid_tertiary...

    Three DNA conformations are believed to be found in nature, A-DNA, B-DNA, and Z-DNA. The "B" form described by James D. Watson and Francis Crick is believed to predominate in cells. [ 2 ] James D. Watson and Francis Crick described this structure as a double helix with a radius of 10 Å and pitch of 34 Å , making one complete turn about its ...

  7. Nucleic acid structure - Wikipedia

    en.wikipedia.org/wiki/Nucleic_acid_structure

    In DNA double helix, the two strands of DNA are held together by hydrogen bonds. The nucleotides on one strand base pairs with the nucleotide on the other strand. The secondary structure is responsible for the shape that the nucleic acid assumes. The bases in the DNA are classified as purines and pyrimidines. The purines are adenine and guanine ...

  8. Nucleic acid sequence - Wikipedia

    en.wikipedia.org/wiki/Nucleic_acid_sequence

    DNA sequencing is the process of determining the nucleotide sequence of a given DNA fragment. The sequence of the DNA of a living thing encodes the necessary information for that living thing to survive and reproduce. Therefore, determining the sequence is useful in fundamental research into why and how organisms live, as well as in applied ...

  9. Histone-modifying enzymes - Wikipedia

    en.wikipedia.org/wiki/Histone-modifying_enzymes

    Like PARPs 2 and 3, the catalytic activity of PARP-1 is activated by discontinuous DNA fragments, DNA fragments with single-stranded breaks. PARP-1 binds histones near the axis where DNA enters and exits the nucleosome and additionally interacts with numerous chromatin-associated proteins which allow for indirect association with chromatin. [30]