Antimicrobial · Self-assembling, disulphide-stabilised α-defensin
Human alpha-defensin 6 (HD-6)
Also known as HD6; DEFA6
A Paneth-cell α-defensin whose surface-triggered self-assembly forms microbial-trapping nanonets in experimental systems.
- Length
- 32 amino acids
- Half-life
- Not well characterised
- Mechanism
- Oxidised HD-6 binds microbial surface features and self-assembles into fibrillar networks termed nanonets, which can entrap microorganisms and restrict epithelial access in experimental models. This predominantly receptor-independent mechanism differs from conventional membrane-lytic activity, although redox state can alter its antimicrobial properties.
- Studied in
- Bacterial entrapment assays, epithelial invasion systems, electron microscopy and transgenic mouse models investigate HD-6 assembly and intestinal barrier interactions.
About Human alpha-defensin 6 (HD-6)
Encoded by DEFA6, human α-defensin 6 is a Paneth-cell peptide identified during molecular characterisation of intestinal defensins. The 100-residue precursor contains a signal peptide and prosegment, while the canonical mature product comprises 32 amino acids. Like HD-5, it contains six cysteines arranged in three α-defensin disulphide bonds. Despite this shared scaffold and neighbouring intestinal expression pattern, its oxidised mature form behaves quite differently from strongly membrane-active defensins in many conventional bacterial assays.
A defining feature of HD-6 is its capacity for hierarchical self-assembly after association with microbial surfaces. Structural and microscopy studies describe oligomers, fibrils and extended nanonets rather than a mechanism requiring a specific cell-surface receptor. These assemblies can entangle bacteria and impede their contact with cultured epithelial cells. Experiments using reduced peptide have revealed additional antimicrobial behaviour, making redox state an important distinction when comparing publications, preparations or functional readouts across laboratory systems.
Laboratory notes
- Record oxidation state and avoid unplanned exposure to reducing agents; reduced and oxidised HD-6 are not functionally interchangeable.
- Pair growth-based assays with microscopy or epithelial invasion measurements, because entrapment may occur without strong growth inhibition.
- Standardise mixing, incubation time and peptide concentration when studying assembly, and distinguish peptide networks from nonspecific precipitation.
Storage and reconstitution basics: storage guide.
Questions about Human alpha-defensin 6 (HD-6)
What are HD-6 nanonets?
They are extended peptide assemblies that form through HD-6 self-association, often around microbial surfaces, and can physically entrap microorganisms.
Does a weak growth-inhibition result mean HD-6 is inactive?
Not necessarily. Conventional growth assays may miss entrapment or reduced epithelial invasion, so the readout must match the proposed mechanism.
Can reduced HD-6 be compared directly with oxidised HD-6?
Only with explicit qualification. Disulphide reduction changes the structural state and can reveal antimicrobial properties distinct from those of the oxidised peptide.
Is Human alpha-defensin 6 (HD-6) for human use?
No. It is supplied strictly for in-vitro laboratory research and is not for human or animal consumption.
Related research peptides
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