The Pharmacology of Defensin

Defensin (DF) is a relatively new cytolytic peptide with molecular weight of 4 kDa and antibacterial activity against a wide range of gram positive and gram negative bacteria. This study describes the development of a method for using recombinant defensin protein with internal standard bovine serum albumin (BSA). Using BSA as an internal standard, using a column, water Enable Q C18 column (internal diameter 250 mm x 6 mm, particle size 300 μm, 300 μm), a simple, accurate and accurate RP-HPLC method Was developed and verified. Quantitative method for defensin protein: acetonitrile (60:40 v / v), 0.1% trifluoroacetic acid mobile phase, flow rate 1 ml / min, d

Human beta defensin is produced by epithelial cells of the respiratory tract and intestinal mucosa. Defensins are small cationic peptides with broad antimicrobial activity against many microbial agents including Gram-positive and Gram-negative bacteria, fungi and enveloped viruses. Defensin is a non-glycosylated peptide containing about 35 amino acid residues while beta defensin has 6 cysteine ​​residues and provides a unique structure. Many bioreactive complement fragments are produced as by-products of cascade activation. Complement fragments can modulate cytokine synthesis and release by directly binding T lymphocytes from the adaptive immune system and bone marrow derived lymphocytes (B lymphocytes) to regulate other parts of the immune system.

Pattern recognition receptors are proteins that are used in almost all organisms to identify molecules associated with pathogens. The antimicrobial peptide known as defensin is an evolutionarily conserved component of the innate immune response seen in all animals and plants and represents the dominant form of systemic immunity in invertebrates. The complement system and phagocytic cells are also used in the life of most invertebrates. Ribonuclease and RNA interference pathways are conserved in all eukaryotes and are thought to play a role in the immune response to the virus.

Defensins are endogenous host defense peptides rich in cysteines expressed in all higher plants. They are believed to play an important role in plant defense against fungal and oomycete pathogens. However, little is known about the antibacterial activity of these peptides. The genome of the model legume plant Medicago truncatula contains 63 genes, each encoding a defensin having a tetrasulfide array. A unique dual domain defensin named MtDef 5 was recently identified as an effective broad spectrum antifungal activity. This 107 amino acid defensin contains 2 domains, each of which is 50 amino acids and is linked by a short peptide APKKVEP. Here we will discuss the bacterial pathogens of two economically important plants, Gram negative wild Xanthomonas campestris and defensin against Gram positive clavalier and its two domains, MtDef 5 A and MtDef 5 B. Antimicrobial activity MtDef 5 inhibits proliferation of X. campestris at micromolar concentration but does not inhibit the growth of C. michiganensis

The mode of action of the dual-domain plant defensin MtDef5 against the bacterial pathogen Xanthomonas campestris