The domain within your query sequence starts at position 52 and ends at position 81; the E-value for the Defensin_beta_2 domain shown below is 2.7e-7.

TCRLGRGKCRRTCIESEKIAGWCKLNFFCC

Defensin_beta_2

Defensin_beta_2
PFAM accession number:PF13841
Interpro abstract (IPR025933):

Defensins are 2-6kDa, cationic, microbicidal peptides active against many Gram-negative and Gram-positive bacteria, fungi, and enveloped viruses [ (PUBMED:8528769) ], containing three pairs of intramolecular disulphide bonds. On the basis of their size and pattern of disulphide bonding, mammalian defensins are classified into alpha, beta and theta categories. Every mammalian species explored thus far has beta-defensins. In cows, as many as 13 beta-defensins exist in neutrophils. However, in other species, beta-defensins are more often produced by epithelial cells lining various organs (e.g. the epidermis, bronchial tree and genitourinary tract).

Defensins are produced constitutively and/or in response to microbial products or proinflammatory cytokines. Some defensins are also called corticostatins (CS) because they inhibit corticotropin-stimulated corticosteroid production. The mechanism(s) by which microorganisms are killed and/or inactivated by defensins is not understood completely. However, it is generally believed that killing is a consequence of disruption of the microbial membrane. The polar topology of defensins, with spatially separated charged and hydrophobic regions, allows them to insert themselves into the phospholipid membranes so that their hydrophobic regions are buried within the lipid membrane interior and their charged (mostly cationic) regions interact with anionic phospholipid head groups and water. Subsequently, some defensins can aggregate to form `channel-like' pores; others might bind to and cover the microbial membrane in a `carpet-like' manner. The net outcome is the disruption of membrane integrity and function, which ultimately leads to the lysis of microorganisms. Some defensins are synthesised as propeptides which may be relevant to this process.

Human, rabbit and guinea-pig beta-defensins, as well as human beta-defensin-2 (hBD2), induce the activation and degranulation of mast cells, resulting in the release of histamine and prostaglandin D2.

The beta defensins are antimicrobial peptides implicated in the resistance of epithelial surfaces to microbial colonisation [ (PUBMED:7628632) ].

GO process:innate immune response (GO:0045087)
GO component:extracellular region (GO:0005576)

This is a PFAM domain. For full annotation and more information, please see the PFAM entry Defensin_beta_2