Summary: Sea anemone cytotoxic protein

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Wikipedia: Sea anemone cytotoxic protein
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This is the Wikipedia entry entitled "Sea anemone cytotoxic protein". More...

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Sea anemone cytotoxic protein Edit Wikipedia article

Anemone_cytotox

crystal structure of the water-soluble state of the pore-forming cytolysin sticholysin ii complexed with phosphorylcholine

Identifiers

Symbol

Anemone_cytotox

Available protein structures:
Pfam	structures
PDB	RCSB PDB; PDBe
PDBsum	structure summary

In molecular biology, the sea anemone cytotoxic proteins are lethal pore-forming peptides and proteins, known collectively as cytolysins or actinoporins. There are several different groups of cytolysins based on their structure and function.^[1] This entry represents the most numerous group, the 20kDa highly basic peptides. These cytolysins form cation-selective pores in sphingomyelin-containing membranes. Examples include equinatoxins (from Actinia equina), sticholysins (from Stichodactyla helianthus), magnificalysins (from Heteractis magnifica), and tenebrosins (from Actinia tenebrosa), which exhibit pore-forming, haemolytic, cytotoxic, and heart stimulatory activities.

Cytolysins adopt a stable soluble structure, which undergoes a conformational change when brought in contact with a membrane, leading to an active, membrane-bound form that inserts spontaneously into the membrane. They often oligomerise on the membrane surface, before puncturing the lipid bilayers, causing the cell to lyse. The 20kDa sea anemone cytolysins require a phosphocholine lipid headgroup for binding, however sphingomyelin is required for the toxin to promote membrane permeability.^[2] The crystal structures of equinotoxin II ^[3] and sticholysin II ^[4] both revealed a compact beta-sandwich consisting of ten strands in two sheets flanked on each side by two short alpha-helices, which is a similar topology to osmotin. It is believed that the beta sandwich structure attaches to the membrane, while a three-turn alpha helix lying on the surface of the beta sheet may be involved in membrane pore formation, possibly by the penetration of the membrane by the helix.

[edit] References

^ Anderluh G, Macek P (February 2002). "Cytolytic peptide and protein toxins from sea anemones (Anthozoa: Actiniaria)". Toxicon 40 (2): 111–24. doi:10.1016/S0041-0101(01)00191-X. PMID 11689232.
^ Anderluh G, Macek P (November 2003). "Dissecting the actinoporin pore-forming mechanism". Structure 11 (11): 1312–3. doi:10.1016/j.str.2003.10.007. PMID 14604518.
^ Hinds MG, Zhang W, Anderluh G, Hansen PE, Norton RS (February 2002). "Solution structure of the eukaryotic pore-forming cytolysin equinatoxin II: implications for pore formation". J. Mol. Biol. 315 (5): 1219–29. doi:10.1006/jmbi.2001.5321. PMID 11827489.
^ Mancheno JM, Martin-Benito J, Martinez-Ripoll M, Gavilanes JG, Hermoso JA (November 2003). "Crystal and electron microscopy structures of sticholysin II actinoporin reveal insights into the mechanism of membrane pore formation". Structure 11 (11): 1319–28. doi:10.1016/j.str.2003.09.019. PMID 14604522.

This article incorporates text from the public domain Pfam and InterPro IPR009104

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Sea anemone cytotoxic protein Provide feedback

Sea anemones are a rich source of cytotoxic proteins. Cytolysins comprise a group of more than 30 highly basic proteins with molecular masses of about 20 kDa. Cytolysins isolated from the sea anemone, Heteractis magnifica, include magnificalysin I (HMg I), magnificalysin II (HMg II) and Heteractis magnifica toxin (HMgtxn). These are highly homologous at their N-terminals. HMg I and II have molecular masses of approximately 19 kDa, and pI values of 9.4 and 10.0, respectively. Cytolysins isolated from other sea anemones Actinia tenebrosa (Tenebrosin-C, TN-C), Actinia equina (Equinatoxin, EqT) and Stichodactyla helianthus (ShC) exhibit pore-forming, haemolytic, cytotoxic, and heart stimulatory activities [1].

Literature references

Wang Y, Chua KL, Khoo HE; , Biochim Biophys Acta 2000;1478:9-18.: A new cytolysin from the sea anemone, Heteractis magnifica: isolation, cDNA cloning and functional expression. PUBMED:10719170 EPMC:10719170

External database links

PANDIT:	PF06369
Pseudofam:	PF06369
SCOP:	1kd6
SYSTERS:	Anemone_cytotox
Transporter classification:	1.C.38

This tab holds annotation information from the InterPro database.

InterPro entry IPR009104

Sea anemones are a rich source of lethal pore-forming peptides and proteins, known collectively as cytolysins or actinoporins. There are several different groups of cytolysins based on their structure and function [PUBMED:11689232]. This entry represents the most numerous group, the 20kDa highly basic peptides. These cytolysins form cation-selective pores in sphingomyelin-containing membranes. Examples include equinatoxins (from Actinia equina), sticholysins (from Stichodactyla helianthus), magnificalysins (from Heteractis magnifica), and tenebrosins (from Actinia tenebrosa), which exhibit pore-forming, haemolytic, cytotoxic, and heart stimulatory activities.

Cytolysins adopt a stable soluble structure, which undergoes a conformational change when brought in contact with a membrane, leading to an active, membrane-bound form that inserts spontaneously into the membrane. They often oligomerise on the membrane surface, before puncturing the lipid bilayers, causing the cell to lyse. The 20kDa sea anemone cytolysins require a phosphocholine lipid headgroup for binding, however sphingomyelin is required for the toxin to promote membrane permeability [PUBMED:14604518]. The crystal structures of equinotoxin II [PUBMED:11827489] and sticholysin II [PUBMED:14604522] both revealed a compact beta-sandwich consisting of ten strands in two sheets flanked on each side by two short alpha-helices, which is a similar topology to osmotin. It is believed that the beta sandwich structure attaches to the membrane, while a three-turn alpha helix lying on the surface of the beta sheet may be involved in membrane pore formation, possibly by the penetration of the membrane by the helix.

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Cellular component	pore complex (GO:0046930)
Molecular function	channel activity (GO:0015267)
Biological process	pore complex assembly (GO:0046931)
	hemolysis in other organism involved in symbiotic interaction (GO:0052331)
	cation transport (GO:0006812)

Domain organisation

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Alignments

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There are various ways to view or download the sequence alignments that we store. We provide several sequence viewers and a plain-text Stockholm-format file for download.

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We make a range of alignments for each Pfam-A family:

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RP15/RP35/RP55/RP75: Representative Proteomes (RPs) at 15%, 35%, 55% and 75% co-membership thresholds
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	Seed (3)	Full (46)	Representative proteomes				NCBI (55)	Meta (0)
	Seed (3)	Full (46)	RP15 (3)	RP35 (8)	RP55 (17)	RP75 (21)	NCBI (55)	Meta (0)
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¹Cannot generate PP/Heatmap alignments for seeds; no PP data available

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Format an alignment

	Seed (3)	Full (46)	Representative proteomes				NCBI (55)	Meta (0)
	Seed (3)	Full (46)	RP15 (3)	RP35 (8)	RP55 (17)	RP75 (21)	NCBI (55)	Meta (0)
Alignment:
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	Seed (3)	Full (46)	Representative proteomes				NCBI (55)	Meta (0)
	Seed (3)	Full (46)	RP15 (3)	RP35 (8)	RP55 (17)	RP75 (21)	NCBI (55)	Meta (0)
Raw Stockholm	Download	Download	Download	Download	Download	Download	Download
Gzipped	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.

External links

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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.

Curation

Seed source:

Pfam-B_14701 (release 9.0)

Previous IDs:

none

Type:

Family

Author:

Moxon SJ

Number in seed:

3

Number in full:

46

Average length of the domain:

153.10 aa

Average identity of full alignment:

36 %

Average coverage of the sequence by the domain:

87.33 %

HMM information

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	25.0	25.0
Trusted cut-off	25.0	25.2
Noise cut-off	20.9	24.3

Model length:

176

Family (HMM) version:

7

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Species distribution

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Interactive tree

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Interactions

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

Anemone_cytotox

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 Anemone_cytotox domain has been found. There are 19 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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Archea	Eukaryota
Bacteria	Other sequences
Viruses	Unclassified
Viroids	Unclassified sequence

Family: Anemone_cytotox (PF06369)

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Summary: Sea anemone cytotoxic protein

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Sea anemone cytotoxic protein Edit Wikipedia article

[edit] References

Sea anemone cytotoxic protein Provide feedback

Literature references

External database links

InterPro entry IPR009104

Gene Ontology

Domain organisation

Alignments

Alignment types

Viewing

Reformatting

Downloading

View options

Format an alignment

Download options

External links

HMM logo

Trees

Curation and family details

Curation

HMM information

Species distribution

Sunburst controls

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How the sunburst is generated

Colouring and labels

Anomalies in the taxonomy tree

Missing taxonomic levels

Unmapped species names

Sub-species

Too many species/sequences

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Annotation

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Species trees

Interactive tree

Interactions

Structures