Everything about Deoxyribose totally explained
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Deoxyribose, also known as
D-Deoxyribose and
2-deoxyribose, is an
aldopentose — a
monosaccharide containing five
carbon atoms, and including an
aldehyde functional group in its linear structure. It is a
deoxy sugar derived from the
pentose sugar ribose by the replacement of the
hydroxyl group at the 2 position with
hydrogen, leading to the net loss of an
oxygen atom. Replacement of the hydroxyl group also shifts the conformation of the ring from C3'-endo to C2'-endo. It has a
chemical formula of
5104; it was discovered in
1929 by
Phoebus Levene.
Ribose forms a five-member ring composed of four carbon atoms and one oxygen.
Hydroxyl groups are attached to three of the carbons. The other carbon and a hydroxyl group are attached to one of the carbon atoms adjacent to the oxygen. In deoxyribose, the carbon furthest from the attached carbon is stripped of the oxygen atom in what would be a
hydroxyl group in ribose. Due to the common C3' and C4'
stereochemistry of D-ribose and D-arabinose, D-2-deoxyribose is also D-2-deoxyarabinose.
Deoxyribofuranose is an alternative name for the ring structure of deoxyribose. This alternative name merely refers to the fact that deoxyribose has a five membered ring consisting of four carbons and an oxygen and is more a structural description than a name.
Biological importance of deoxyribose
Ribose and 2-deoxyribose derivatives have an important role in biology. Among the most important derivatives are those with phosphate groups attached at the 5 position. Mono-, di-, and triphosphate forms are important, as well as 3-5 cyclic monophosphates. There are also important diphosphate dimers called coenzymes that
purines and
pyrimidines form an important class of compounds with ribose and deoxyribose. When these purine and pyrimidine derivatives are coupled to a ribose sugar, they're called
nucleosides. In these compounds, the convention is to put a ′ (pronounced "prime") after the carbon numbers of the sugar, so that in nucleoside derivatives a name might include, for instance, the term "5′-monophosphate", meaning that the phosphate group is attached to the fifth carbon of the sugar, and not to the base. The bases are attached to the 1′ ribose carbon in the common nucleosides. Phosphorylated nucleosides are called
nucleotides.
One of the common bases is
adenine (a purine derivative); coupled to ribose it's called
adenosine; coupled to deoxyribose it's called
deoxyadenosine. The 5′-triphosphate derivative of adenosine, commonly called
ATP, for
adenosine
tri
phosphate, is an important energy transport molecule in cells.
See
Nucleic acid nomenclature for a diagram showing the numbered positions in a 5′-monophosphate nucleotide.
2-Deoxyribose and ribose nucleotides are often found in unbranched 5′-3′
polymers. In these structures, the 3′carbon of one
monomer unit is linked to a phosphate that's attached to the 5′carbon of the next unit, and so on. These polymer chains often contain many millions of monomer units. Since long polymers have physical properties distinctly different from those of small molecules, they're called
macromolecules. The sugar-phosphate-sugar chain is called the backbone of the polymer. One end of the backbone has a free 5′phosphate, and the other end has a free 3′OH group. The backbone structure is independent of which particular bases are attached to the individual sugars.
Genetic material in earthly life often contains poly 5′-3′, 2′-deoxyribose nucleotides, in structures called
chromosomes, where each monomer is one of the nucleotides deoxy-
adenine,
thymine,
guanine or
cytosine. This material is commonly called
deoxyribonucleic acid, or simply
DNA for short.
DNA in chromosomes forms very long helical structures containing two molecules with the backbones running in opposite directions on the outside of the helix and held together by hydrogen bonds between complementary nucleotide bases lying between the helical backbones. The lack of the 2′ hydroxyl group in DNA appears to allow the backbone the flexibility to assume the full conformation of the long double-helix, which involves not only the basic helix, but additional coiling necessary to fit these very long molecules into the very small volume of a cell nucleus.
In contrast, very similar molecules, containing ribose instead of deoxyribose, and known generically as
RNA, are known to form only relatively
short double-helical complementary base paired structures. These are well known, for instance, in
ribosomal RNA molecules and in transfer RNA (
tRNA), where so-called
hairpin structures from
palindromic sequences within one molecule. Hi
Further Information
Get more info on 'Deoxyribose'.
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