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69  structures 40  species 1  interaction 260  sequences 4  architectures

Family: Defensin_beta (PF00711)

Summary: Beta defensin

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Beta defensin Provide feedback

The beta defensins are antimicrobial peptides implicated in the resistance of epithelial surfaces to microbial colonisation [1].

Literature references

  1. Bensch KW, Raida M, Magert HJ, Schulz-Knappe P, Forssmann WG; , FEBS Lett 1995;368:331-335.: hBD-1: a novel beta-defensin from human plasma. PUBMED:7628632 EPMC:7628632

  2. Liu L, Zhao C, Heng HH, Ganz T; , Genomics 1997;43:316-320.: The human beta-defensin-1 and alpha-defensins are encoded by adjacent genes: two peptide families with differing disulfide topology share a common ancestry. PUBMED:9268634 EPMC:9268634


External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR001855

Defensins are 2-6 kDa, 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.

This entry represents a range of Beta defensins.

Gene Ontology

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Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Pfam Clan

This family is a member of clan Defensin (CL0075), which has the following description:

This clan includes diverse defensins as well as myotoxins.

The clan contains the following 9 members:

Defensin_1 Defensin_3 Defensin_4 Defensin_beta Defensin_beta_2 Defensin_big Inhibitor_I68 Myotoxins Toxin_4

Alignments

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(47)
Full
(260)
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(812)
NCBI
(1188)
Meta
(1)
RP15
(59)
RP35
(80)
RP55
(161)
RP75
(233)
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  Seed
(47)
Full
(260)
Representative proteomes UniProt
(812)
NCBI
(1188)
Meta
(1)
RP15
(59)
RP35
(80)
RP55
(161)
RP75
(233)
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  Seed
(47)
Full
(260)
Representative proteomes UniProt
(812)
NCBI
(1188)
Meta
(1)
RP15
(59)
RP35
(80)
RP55
(161)
RP75
(233)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download   Download   Download  
Gzipped Download   Download   Download   Download   Download   Download   Download   Download   Download  

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

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Trees

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Curation and family details

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Curation View help on the curation process

Seed source: Pfam-B_675 (release 2.1)
Previous IDs: none
Type: Domain
Author: Bateman A
Number in seed: 47
Number in full: 260
Average length of the domain: 35.20 aa
Average identity of full alignment: 33 %
Average coverage of the sequence by the domain: 46.68 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 17690987 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 21.0 21.0
Trusted cut-off 21.1 21.0
Noise cut-off 20.8 20.8
Model length: 36
Family (HMM) version: 17
Download: download the raw HMM for this family

Species distribution

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Interactions

There is 1 interaction for this family. More...

Defensin_beta

Structures

For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Defensin_beta domain has been found. There are 69 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

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