Deoxyribose, or more precisely 2-deoxyribose, is a monosaccharide with idealized formula H−(C=O)−(CH2)−(CHOH)3−H. Its name indicates that it is a deoxy sugar, meaning that it is derived from the sugar ribose by loss of a hydroxy group. Discovered in 1929 by Phoebus Levene,
Structure
Several isomers exist with the formula H−(C=O)−(CH
2)−(CHOH)
3−H, but in deoxyribose all the
hydroxyl groups are on the same side in the Fischer projection. The term "2-deoxyribose" may refer to either of two
: the biologically important -2-deoxyribose and to the rarely encountered mirror image
L-Deoxyribose.
[C Bernelot-Moens and B Demple (1989), Multiple DNA repair activities for 3′-deoxyribose fragments in Escherichia coli. Nucleic Acids Research, Volume 17, issue 2, p. 587–600.] -2-deoxyribose is a precursor to the
nucleic acid DNA. 2-deoxyribose is an
aldopentose, that is, a monosaccharide with five
carbon and having an
aldehyde functional group.
In aqueous solution, deoxyribose primarily exists as a mixture of three structures: the linear form H−(C=O)−(CH2)−(CHOH)3−H and two ring forms, deoxyribofuranose ("C3′-endo"), with a five-membered ring, and deoxyribopyranose ("C2′-endo"), with a six-membered ring. The latter form is predominant (whereas the C3′-endo form is favored for ribose).
Biological importance
As a component of DNA, 2-deoxyribose derivatives have an important role in biology.
[C.Michael Hogan. 2010. Deoxyribonucleic acid. Encyclopedia of Earth. National Council for Science and the Environment. eds. S.Draggan and C.Cleveland. Washington DC] The
DNA (deoxyribonucleic acid) molecule, which is the main repository of
genetics information in life, consists of a long chain of deoxyribose-containing units called
nucleotides, linked via
phosphate groups. In the standard nucleic acid nomenclature, a DNA nucleotide consists of a deoxyribose molecule with an organic base (usually
adenine,
thymine,
guanine or
cytosine) attached to the 1′ ribose carbon. The 5′ hydroxyl of each deoxyribose unit is replaced by a
phosphate (forming a
nucleotide) that is attached to the 3′ carbon of the deoxyribose in the preceding unit.
The absence of the 2′ hydroxyl group in deoxyribose is apparently responsible for the increased mechanical flexibility of DNA compared to RNA, which allows it to assume the double-helix conformation, and also (in the ) to be compactly coiled within the small cell nucleus. The double-stranded DNA molecules are also typically much longer than RNA molecules. The backbone of RNA and DNA are structurally similar, but RNA is single stranded, and made from ribose as opposed to deoxyribose.
Other biologically important derivatives of deoxyribose include mono-, di-, and triphosphates, as well as 3′-5′ cyclic monophosphates.
Biosynthesis
Deoxyribose is generated from ribose 5-phosphate by enzymes called ribonucleotide reductases. These enzymes catalyse the deoxygenation process.
Angiogenesis
In one study, deoxyribose was shown to have pro-
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