Defensins are small cysteine-rich cationic peptides containing three or four disulfide bridges. They are divided into families on the basis of the spatial distribution of their cysteine residues. Three families, the α-, β- and θ-defensins, can be distinguished in mammals. α- and β-defensins are characterized by antiparallel β-sheet structures stabilized by three disulfide bonds. The θ-defensins are found in rhesus monkey and some other non-human primates but not in human, chimpanzee and gorilla. They consist of two nine amino acid peptides derived from different precursor proteins joined by head-to-tail cyclization. Defensins protect human barriers from commensal and pathogenic microorganisms. Human α-defensin 6 (HD-6 with sequence AFTCHCRRSCYSTEYSYGTCTVMGINHRFCCL) is produced exclusively by small intestinal paneth cells. It is an antimicrobial peptide acting via 2 distinct antimicrobial mechanisms: HD-6 kills specific microbes depending on the local reducing environmental conditions, whereas known microbial trapping by extracellular net structures is independent of the reducing milieu.
Size
50 μg
Concentration
Lyophilized product in PBS, containing 50 μg HD-6.