decamer

A decamer is a macromolecular complex composed of ten subunits. The term is used across biochemistry, structural biology, and materials science to describe assemblies with ten repeating units. Decamers can be homodecamers (ten identical subunits) or heterodecamers (two or more distinct subunit types). They commonly adopt ring-like or staggered arrangements with tenfold (C10) symmetry, though other geometries are possible.

Etymology: from Latin deca- meaning ten and -mer meaning part.

In biology and related fields, decamers occur in protein assemblies, nucleic acid binding proteins, and some viral components. The ten-subunit organization can enable cooperative interactions among subunits, allosteric regulation, or the formation of a central channel or cavity. In some systems, decamers assemble from smaller oligomers or disassemble in response to ligands, pH, or ionic strength.

Characterization: Determining decameric stoichiometry and symmetry relies on structural and biophysical methods such as X-ray crystallography, cryo-electron microscopy, analytical ultracentrifugation, and size-exclusion chromatography with multi-angle light scattering.

See also: oligomer, decameric protein, symmetry in biological assemblies.

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