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  2. Z-DNA - Wikipedia

    en.wikipedia.org/wiki/Z-DNA

    Z-DNA is one of the many possible double helical structures of DNA. It is a left-handed double helical structure in which the helix winds to the left in a zigzag pattern, instead of to the right, like the more common B-DNA form. Z-DNA is thought to be one of three biologically active double-helical structures along with A-DNA and B-DNA.

  3. Obsolete models of DNA structure - Wikipedia

    en.wikipedia.org/wiki/Obsolete_models_of_DNA...

    Under torsional stress, a Z-DNA structure can form with opposite twist to B-form DNA, but this is rare within the cellular environment. [24] The discovery of topoisomerases and gyrases , enzymes that can change the linking number of circular nucleic acids and thus "unwind" and "rewind" the replicating bacterial chromosome, solved the ...

  4. Nucleic acid double helix - Wikipedia

    en.wikipedia.org/wiki/Nucleic_acid_double_helix

    The double-helix model of DNA structure was first published in the journal Nature by James Watson and Francis Crick in 1953, [6] (X,Y,Z coordinates in 1954 [7]) based on the work of Rosalind Franklin and her student Raymond Gosling, who took the crucial X-ray diffraction image of DNA labeled as "Photo 51", [8] [9] and Maurice Wilkins, Alexander Stokes, and Herbert Wilson, [10] and base-pairing ...

  5. Timeline of the history of genetics - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_the_history_of...

    1996: Alexander Rich discovered the Z-DNA, a type of DNA which is in a transient state, that is in some cases associated with DNA transcription. [64] The Z-DNA form is more likely to occur in regions of DNA rich in cytosine and guanine with high salt concentrations. [65]

  6. Nucleic acid tertiary structure - Wikipedia

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

    The double helix is the dominant tertiary structure for biological DNA, and is also a possible structure for RNA. 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]

  7. DNA - Wikipedia

    en.wikipedia.org/wiki/DNA

    Deoxyribonucleic acid (/ d iː ˈ ɒ k s ɪ ˌ r aɪ b oʊ nj uː ˌ k l iː ɪ k,-ˌ k l eɪ-/ ⓘ; [1] DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of all known organisms and many ...

  8. Non B-DNA - Wikipedia

    en.wikipedia.org/wiki/Non_B-DNA

    Non-B DNA can have significant implications for DNA biology and human health. For example, Z-DNA has been implicated in immunity and autoimmune diseases, such as lupus and arthritis. [6] H-DNA has been implicated in genomic instability and cancer, and G-quadruplexes have been linked to telomere maintenance, [7] oncogene activation, and cancer. [8]

  9. Chromatin - Wikipedia

    en.wikipedia.org/wiki/Chromatin

    In nature, DNA can form three structures, A-, B-, and Z-DNA. A- and B-DNA are very similar, forming right-handed helices, whereas Z-DNA is a left-handed helix with a zig-zag phosphate backbone. Z-DNA is thought to play a specific role in chromatin structure and transcription because of the properties of the junction between B- and Z-DNA.