Deoxyribonucleic acid double helix structure (DNA double helix)

The **deoxyribonucleic acid (DNA) double helix** is the fundamental structural arrangement of genomic material in all living organisms. It consists of two antiparallel strands composed of repeating nucleotide units—each containing a phosphate group, deoxyribose sugar, and one of four nitrogenous bases (adenine [A], thymine [T], cytosine [C], guanine [G])—that wind around each other in a right-handed spiral resembling a twisted ladder[1][2][3][4]. The sugar-phosphate backbones form the sides of this "ladder," while complementary base pairs connect across its center via hydrogen bonds—A pairing with T and C pairing with G[1][2][3][4]. The most common natural conformation is B-DNA, featuring about 10 base pairs per helical turn and distinct major and minor grooves that facilitate protein binding[5][6]. This structure underlies essential biological processes such as **genetic information storage**, **replication**, and **transcription**. While many drugs interact directly with DNA by binding within its grooves or intercalating between bases to disrupt cellular processes—for example in cancer chemotherapy—the "DNA double helix" itself is not considered a specific therapeutic target like an enzyme or receptor[2][5].

Other names

DNA duplexDouble-stranded DNAB-DNA (most common form)Nucleic acid double helix