Summary: Melittin
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Melittin Provide feedback
No Pfam abstract.
Literature references
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Terwilliger TC, Eisenberg D; , J Biol Chem 1982;257:6016-6022.: The structure of melittin. II. Interpretation of the structure. PUBMED:7076662 EPMC:7076662
External database links
SCOP: | 2mlt |
Transporter classification: | 1.C.18 |
This tab holds annotation information from the InterPro database.
InterPro entry IPR002116
Allergies are hypersensitivity reactions of the immune system to specific substances called allergens (such as pollen, stings, drugs, or food) that, in most people, result in no symptoms. A nomenclature system has been established for antigens (allergens) that cause IgE-mediated atopic allergies in humans [WHO/IUIS Allergen Nomenclature Subcommittee King T.P., Hoffmann D., Loewenstein H., Marsh D.G., Platts-Mills T.A.E., Thomas W. Bull. World Health Organ. 72:797-806(1994)]. This nomenclature system is defined by a designation that is composed of the first three letters of the genus; a space; the first letter of the species name; a space and an Arabic number. In the event that two species names have identical designations, they are discriminated from one another by adding one or more letters (as necessary) to each species designation.
The allergens in this family include allergens with the following designations: Api m 3.
Melittin is the principal protein component of the venom of the honeybee, Apis mellifera. It inhibits protein kinase C, Ca2+/calmodulin-dependent protein kinase II, myosin light chain kinase and Na+/K+-ATPase (synaptosomal membrane) and is a cell membrane lytic factor. Melittin is a small peptide with no disulphide bridge; the N-terminal part of the molecule is predominantly hydrophobic and the C-terminal part is hydrophilic and strongly basic.
The molecular mechanisms underlying the various effects of melittin on membranes have not been completely defined and much of the evidence indicates that different molecular mechanisms may underlie different actions of the peptide [PUBMED:2187536].
Extensive work with melittin has shown that the venom has multiple effects, probably, as a result of its interaction with negatively changed phospholipids. It inhibits well known transport pumps such as the Na+-K+-ATPase and the H+-K+-ATPase. Melittin increases the permeability of cell membranes to ions, particularly Na+ and indirectly Ca2+, because of the Na+-Ca2+-exchange. This effect results in marked morphological and functional changes, particularly in excitable tissues such as cardiac myocytes. In some other tissues, e.g., cornea, not only Na+ but Cl- permeability is also increased by melittin. Similar effects to melittin on H+-K+-ATPase have been found with the synthetic amphipathic polypeptide Trp-3 [PUBMED:10072885].
The study of melittin in model membranes has been useful for the development of methodology for determination of membrane protein structures. A molecular dynamics simulation of melittin in a hydrated dipalmitoylphosphatidylcholine (DPPC) bilayer was carried out. The effect of melittin on the surrounding membrane was localised to its immediate vicinity, and its asymmetry with respect to the two layers may be a result of the fact that it is not fully transmembranal. Melittin's hydrophilic C terminus anchors it at the extracellular interface, leaving the N terminus "loose" in the lower layer of the membrane [PUBMED:10692322].
Gene Ontology
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
Cellular component | extracellular region (GO:0005576) |
Molecular function | protein kinase inhibitor activity (GO:0004860) |
Domain organisation
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Alignments
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Full (3) |
Representative proteomes | UniProt (24) |
NCBI (50) |
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PP/heatmap | 1 |
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Seed (1) |
Full (3) |
Representative proteomes | UniProt (24) |
NCBI (50) |
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RP15 (0) |
RP35 (0) |
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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
Seed source: | SCOP |
Previous IDs: | none |
Type: | Family |
Sequence Ontology: | SO:0100021 |
Author: |
Bateman A |
Number in seed: | 1 |
Number in full: | 3 |
Average length of the domain: | 24.30 aa |
Average identity of full alignment: | 68 % |
Average coverage of the sequence by the domain: | 43.71 % |
HMM information
HMM build commands: |
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 47079205 -E 1000 --cpu 4 HMM pfamseq
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Model details: |
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Model length: | 26 | ||||||||||||
Family (HMM) version: | 18 | ||||||||||||
Download: | download the raw HMM for this family |
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 Melittin domain has been found. There are 10 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 sequence.
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