What is the name of the bond between a sugar and a base in a nucleotide?

The bond between a sugar and a base in a nucleotide is a glycosidic bond. More specifically, DNA and RNA nucleotides contain an N-glycosidic bond, because a nitrogen atom in the nucleobase is linked to the sugar. In DNA, the sugar is deoxyribose; in RNA, it is ribose.

This bond joins the sugar’s anomeric carbon to a nitrogen in the base. Adenine and guanine attach through nitrogen N9, while cytosine, thymine, and uracil attach through nitrogen N1. The sugar and base together form a nucleoside; adding one or more phosphate groups makes it a nucleotide.

A common mix-up is confusing this bond with the bonds holding the DNA backbone together. Phosphodiester bonds connect neighboring sugars and phosphates along each strand, while hydrogen bonds join complementary bases across the double helix. Peptide bonds belong to proteins, not nucleic acids.

Glycosidic bonds are also important in DNA repair. DNA glycosylase enzymes can remove damaged bases by breaking the sugar-base N-glycosidic bond, creating an abasic site that is processed during base-excision repair.