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14  structures 158  species 0  interactions 314  sequences 1  architecture

Family: Defensin_2 (PF01097)

Summary: Arthropod defensin

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This is the Wikipedia entry entitled "Arthropod defensin". More...

Arthropod defensin Edit Wikipedia article

Arthropod defensin
PDB 1ica EBI.jpg
Structure of insect defensin A.[1]
Identifiers
Symbol Defensin_2
Pfam PF01097
InterPro IPR001542
PROSITE PDOC00356
SCOP 1ica
SUPERFAMILY 1ica
TCDB 1.C.47
OPM superfamily 61
OPM protein 1l4v

Arthropod defensins are a family of insect and scorpion cysteine-rich antibacterial peptides, primarily active against Gram-positive bacteria.[2][3][4][5][6] All these peptides range in length from 38 to 51 amino acids. There are six conserved cysteines all involved in intrachain disulfide bonds. The role of these highly conserved cysteines is not known. Studies have shown that disulfide bonds are not required for antimicrobial activity.[1][7] Mammalian defensins also do not require disulfide bonds to exhibit antimicrobial activity. [2][8] Furthermore, it was also shown that the N-terminal helix region in arthropod or insect defensins is also not required for antimicrobial activity of these peptides.[3][9]

A schematic representation of peptides from the arthropod defensin family is shown below.

           +----------------------------+
           |                            |
         xxCxxxxxxxxxxxxxxCxxxCxxxxxxxxxCxxxxxCxCxx
                          |   |               | |
                          +---|---------------+ |
                              +-----------------+

'C': conserved cysteine involved in a disulfide bond.

Although low level sequence similarities have been reported[2] between the arthropod defensins and mammalian defensins, the topological arrangement of the disulfide bonds as well as the tertiary structure[10] are completely different in the two families.

Notes

  1. ^ Cornet B, Bonmatin JM, Hetru C, Hoffmann JA, Ptak M, Vovelle F (May 1995). "Refined three-dimensional solution structure of insect defensin A". Structure 3 (5): 435–48. doi:10.1016/S0969-2126(01)00177-0. PMID 7663941. 
  2. ^ a b Dunbar B, Lambert J, Keppi E, Wicker C, Lepage P, Hoffmann J, Fothergill J, Dimarcq JL, Reichhart JM, Van Dorsselaer A (1989). "Insect immunity: isolation from immune blood of the dipteran Phormia terranovae of two insect antibacterial peptides with sequence homology to rabbit lung macrophage bactericidal peptides". Proc. Natl. Acad. Sci. U.S.A. 86 (1): 262–266. doi:10.1073/pnas.86.1.262. PMC 286444. PMID 2911573. 
  3. ^ Kobayashi K, Fujiwara S, Imai J, Fujiwara M, Yaeshima T, Kawashima T (1990). "A potent antibacterial protein in royal jelly. Purification and determination of the primary structure of royalisin". J. Biol. Chem. 265 (19): 11333–11337. PMID 2358464. 
  4. ^ Yamada K, Natori S (1993). "Purification, sequence and antibacterial activity of two novel sapecin homologues from Sarcophaga embryonic cells: similarity of sapecin B to charybdotoxin". Biochem. J. 291: 275–279. PMC 1132513. PMID 8471044. 
  5. ^ Cociancich S, Bulet P, Hoffmann JA, Hetru C, Lambert J, Hoffmann D, Dimarcq JL, Reichhart JM (1991). "Insect immunity. Isolation from a coleopteran insect of a novel inducible antibacterial peptide and of new members of the insect defensin family". J. Biol. Chem. 266 (36): 24520–24525. PMID 1761552. 
  6. ^ Cociancich S, Bulet P, Hoffmann JA, Hegy G, Hetru C, Reuland M, Sauber F, Bischoff R, Van Dorsselaer A (1992). "A novel insect defensin mediates the inducible antibacterial activity in larvae of the dragonfly Aeschna cyanea (Paleoptera, Odonata)". Eur. J. Biochem. 209 (3): 977–984. doi:10.1111/j.1432-1033.1992.tb17371.x. PMID 1425705. 
  7. ^ Jobin Varkey, Shashi Singh, Ramakrishnan Nagaraj. Antibacterial activity of linear peptides spanning the carboxy-terminal β-sheet domain of arthropod defensins
  8. ^ Jobin Varkey, Ramakrishnan Nagaraj. Antibacterial Activity of Human Neutrophil Defensin HNP-1 Analogs without Cysteines
  9. ^ Jobin Varkey, Shashi Singh, Ramakrishnan Nagaraj. Antibacterial activity of linear peptides spanning the carboxy-terminal β-sheet domain of arthropod defensins
  10. ^ Natori S, Kohda D, Hanzawa H, Shimada I, Kuzuhara T, Komano H, Inagaki F, Arata Y (1990). "1H nuclear magnetic resonance study of the solution conformation of an antibacterial protein, sapecin". FEBS Lett. 269 (2): 413–420. doi:10.1016/0014-5793(90)81206-4. PMID 2401368. 

Further reading

  • Cornet B, Bonmatin JM, Hetru C, Hoffmann JA, Ptak M, Vovelle F (May 1995). "Refined three-dimensional solution structure of insect defensin A". Structure 3 (5): 435–48. doi:10.1016/S0969-2126(01)00177-0. PMID 7663941. 

References


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Literature references

  1. Cornet B, Bonmatin JM, Hetru C, Hoffmann JA, Ptak M, Vovelle F; , Structure 1995;3:435-448.: Refined three-dimensional solution structure of insect defensin A. PUBMED:7663941 EPMC:7663941


External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR001542

Arthropod defensins are a family of insect and scorpion cysteine-rich antibacterial peptides, primarily active against Gram-positive bacteria [PUBMED:2911573, PUBMED:2358464, PUBMED:8471044, PUBMED:1761552, PUBMED:1425705]. All these peptides range in length from 38 to 51 amino acids. There are six conserved cysteines all involved in intrachain disulphide bonds.

A schematic representation of peptides from the arthropod defensin family is shown below.

        +----------------------------+
        |                   | 
       xxCxxxxxxxxxxxxxxCxxxCxxxxxxxxxCxxxxxCxCxx
                  |  |          | |
                  +---|---------------+ |
                     +-----------------+
'C': conserved cysteine involved in a disulphide bond.

Although low level sequence similarities have been reported [PUBMED:2911573] between the arthropod defensins and mammalian defensins, the topological arrangement of the disulphide bonds as well as the tertiary structure [PUBMED:2401368] are completely different in the two families.

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 Knottin_1 (CL0054), which has the following description:

This clan includes a number of toxin families that share the knottin structure. These families come from scorpions, plants and arthropods.

The clan contains the following 11 members:

Defensin_2 DUF2667 Gamma-thionin SCRL SLR1-BP Toxin_17 Toxin_2 Toxin_3 Toxin_37 Toxin_38 Toxin_5

Alignments

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RP35
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  Seed
(15)
Full
(314)
Representative proteomes NCBI
(362)
Meta
(0)
RP15
(23)
RP35
(27)
RP55
(51)
RP75
(58)
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  Seed
(15)
Full
(314)
Representative proteomes NCBI
(362)
Meta
(0)
RP15
(23)
RP35
(27)
RP55
(51)
RP75
(58)
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External links

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Trees

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Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

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Seed source: Prosite
Previous IDs: Defensin; Arthro_defensin;
Type: Domain
Author: Finn RD, Bateman A
Number in seed: 15
Number in full: 314
Average length of the domain: 33.90 aa
Average identity of full alignment: 42 %
Average coverage of the sequence by the domain: 40.60 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 20.4 20.4
Trusted cut-off 20.4 20.4
Noise cut-off 20.2 20.2
Model length: 34
Family (HMM) version: 13
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Species distribution

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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_2 domain has been found. There are 14 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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