Dodecameric

Dodecameric refers to molecular assemblies composed of twelve subunits. The term is used across chemistry and biology to describe proteins, nucleic acids, and protein complexes that assemble into twelve-unit structures. The subunits may be identical (homododecamer) or non-identical (heterododecamer) and can arrange in symmetry modes such as a cyclic twelvefold ring (C12) or a dihedral assembly formed by two hexameric rings (D6).

Such assemblies can enhance stability and create large, specialized interfaces for binding ligands, substrates, or nucleic acids. They may display cooperative or allosteric regulation, where binding at one subunit affects others, and can generate enclosed cavities or channels that influence catalysis or transport.

Occurrence and examples: Dodecameric arrangements appear in various biological contexts. In tailed bacteriophages, portal proteins frequently assemble as dodecameric rings at the capsid vertex, enabling genome entry and exit. In archaea and bacteria, small proteins such as dodecin form dodecameric complexes that bind small molecules and participate in regulatory processes.

See also: oligomer, multimer.