dubbelhelixens

Dubbelhelixens refers to the double helix structures found in nucleic acids, most notably DNA, and to instances where two polynucleotide strands form a single, helical unit. The term is used in Dutch-language scientific writing; in English, the customary term is double helix or double helices.

Structure and composition: A dubbelhelix consists of two long polynucleotide chains that run in opposite directions (antiparallel) and wind around a common axis to form a right-handed spiral in canonical B-DNA. The sugar-phosphate backbones lie on the exterior, while the bases pair internally via hydrogen bonds: adenine with thymine, and guanine with cytosine. The base pairing makes the two strands complementary and thermodynamically stable. The molecule exhibits major and minor grooves that proteins recognize during replication and transcription.

Function and biology: DNA dubbelhelix encodes genetic information through its sequence of bases. During replication, the strands separate and serve as templates for semi-conservative assembly of new complementary strands. DNA repair, recombination, and gene regulation rely on the geometry and chemistry of the helix.

Variants: In nature, DNA can adopt several helix forms, notably B-DNA, A-DNA, and Z-DNA, each with distinct geometries. RNA can form RNA duplexes with similar base pairing under specific conditions, though many RNAs are single-stranded.

Discovery and terminology: The double-helix model was proposed in 1953 by Watson and Crick, based on Rosalind Franklin’s X-ray diffraction data. The Dutch term dubbelhelixens mirrors the English concept of double helices.