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After realizing the structural similarity of the A:T and C:G pairs, Watson and Crick soon produced their double helix model of DNA with the hydrogen bonds at the core of the helix providing a way to unzip the two complementary strands for easy replication: the last key requirement for a likely model of the genetic molecule.
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 ...
The first reports of a double helix molecular model of B-DNA structure were made by James Watson and Francis Crick in 1953. [ 5 ] [ 6 ] That same year, Maurice F. Wilkins, A. Stokes and H.R. Wilson, reported the first X-ray patterns of in vivo B-DNA in partially oriented salmon sperm heads.
The double helix is an important tertiary structure in nucleic acid molecules which is intimately connected with the molecule's secondary structure. A double helix is formed by regions of many consecutive base pairs. The nucleic acid double helix is a spiral polymer, usually right-handed, containing two nucleotide strands which base pair together.
Z-DNA is a relatively rare left-handed double-helix. Given the proper sequence and superhelical tension, it can be formed in vivo but its function is unclear. It has a more narrow, more elongated helix than A or B. Z-DNA's major groove is not really a groove, and it has a narrow minor groove.
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]
By convention, if the base sequence of a single strand of DNA is given, the left end of the sequence is the 5′ end, while the right end of the sequence is the 3′ end. The strands of the double helix are anti-parallel, with one being 5′ to 3′, and the opposite strand 3′ to 5′.
Double helix, the structure of DNA; Double helix (geometry), two helices with the same axis differing by a translation along the axis; Double Helix Nebula, a gaseous nebula in the Milky Way Galaxy; Double helical gear, also known as a herringbone gear; The Helix Bridge, a bridge shaped as the double helix located at the Marina Bay, Singapore ...