deoxyribose

Deoxyribose is a five-carbon sugar that serves as a key component of deoxyribonucleic acid (DNA). It is a missing-oxygen version of ribose, specifically 2'-deoxyribose, with the chemical formula C5H10O4. The name reflects its derivation from ribose by the removal of an oxygen atom at the 2' position.

In solution, deoxyribose can form cyclic structures known as furanose rings, existing mainly in two anomeric forms called alpha and beta. In DNA, the beta-anomer predominates and the sugar is typically in the D-configuration. The sugar adopts different ring puckers depending on the DNA form, commonly described as C2'-endo in B-form DNA and C3'-endo in A-form DNA, which influence the overall geometry of the double helix.

Deoxyribose is the structural backbone of DNA, linking with nucleobases to form deoxynucleotides. Each sugar is attached to a nucleobase (adenine, guanine, cytosine, or thymine) to form a deoxynucleoside (deoxyadenosine, deoxyguanosine, deoxycytidine, or deoxythymidine). Phosphate groups connect the 5' phosphate of one deoxyribose to the 3' hydroxyl of the next, creating the phosphodiester backbone that folds to form the DNA double helix.

Compared with ribose, the absence of the 2'-hydroxyl group in deoxyribose reduces chemical reactivity and makes DNA more chemically stable, contributing to DNA’s role as a long-term storage of genetic information. Deoxyribose is therefore absent from RNA and is distinctive to DNA.

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