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Oleosin Edit Wikipedia article
Oleosins are structural proteins found in vascular plant oil bodies and found in plant cells. Oil bodies are not considered organelles because they have a single layer membrane and lack the pre-requisite double layer membrane in order to be considered an organelle. They are found in plant parts with high oil content that undergo extreme desiccation as part of their maturation process, and help stabilize the bodies.
Oleosins are proteins of 16 kDa to 24 kDa and are composed of three domains: an N-terminal hydrophilic region of variable length (from 30 to 60 residues); a central hydrophobic domain of about 70 residues and a C-terminal amphipathic region of variable length (from 60 to 100 residues). The central hydrophobic domain is proposed to be made up of beta-strand structure and to interact with the lipids. It is the only domain whose sequence is conserved. Models show oleosins having a hairpin-like hydrophobic shape that is inserted inside the triacylglyceride (TAG), while the hydrophilic parts are left outside oil bodies.
Oleosins have been found on oil bodies of seeds, tapetum cells, and pollen but not fruits. Instead of a stabilizer of oil bodies, oleosins are believed to be involved in water-uptaking of pollen on stigma.
Use in Purification of Recombinant Protein
Oleosins provide an easy way of purifying proteins which have been produced recombinantly in plants. If the protein is made as a fusion protein with oleosin and a protease recognition site is incorporated between them, the fusion protein will sit in the membrane of the oil body, which can be easily isolated by centrifugation. The oil droplets can then be mixed with aqueous medium again, and oleosin cleaved from the protein of interest. Centrifugation will cause two phases to separate again, and the aqueous medium now contains the purified protein.
- Hsieh, Kai; Anthony H.C. Huang (September 2005). "Lipid-rich tapetosomes in Brassica tapetum are composed of oleosin-coated oil droplets and vesicles, both assembled in and then detached from the endoplasmic reticulum". The Plant Journal 43 (6): 889–99. doi:10.1111/j.1365-313X.2005.02502.x. PMC 1867322. PMID 17307923.
- Tzen JT, Lie GC, Huang AH (August 1992). "Characterization of the charged components and their topology on the surface of plant seed oil bodies". J. Biol. Chem. 267 (22): 15626–34. PMID 1639802.
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This tab holds annotation information from the InterPro database.
InterPro entry IPR000136Oleosins [PUBMED:1989697] are the proteinaceous components of plants' lipid storage bodies called oil bodies. Oil bodies are small droplets (0.2 to 1.5 mu-m in diameter) containing mostly triacylglycerol that are surrounded by a phospholipid/ oleosin annulus. Oleosins may have a structural role in stabilising the lipid body during dessication of the seed, by preventing coalescence of the oil. They may also provide recognition signals for specific lipase anchorage in lipolysis during seedling growth. Oleosins are found in the monolayer lipid/ water interface of oil bodies and probably interact with both the lipid and phospholipid moieties. Oleosins are proteins of 16 Kd to 24 Kd and are composed of three domains: an N-terminal hydrophilic region of variable length (from 30 to 60 residues); a central hydrophobic domain of about 70 residues and a C-terminal amphipathic region of variable length (from 60 to 100 residues). The central hydrophobic domain is proposed to be made up of beta-strand structure and to interact with the lipids [PUBMED:1639802]. It is the only domain whose sequence is conserved.
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Cellular component||integral to membrane (GO:0016021)|
|monolayer-surrounded lipid storage body (GO:0012511)|
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This is the GT-C clan that contains diverse glycosyltransferases that possess 8-13 predicted transmembrane segments .
The clan contains the following 21 members:ALG3 Alg6_Alg8 Arabinose_trans DIE2_ALG10 DUF1420 DUF2029 DUF2079 DUF2142 DUF2723 EpsG Glucan_synthase Glyco_transf_22 Mannosyl_trans Mannosyl_trans2 Oleosin PIG-U PMT PMT_2 PTPS_related STT3 YfhO
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Curation and family details
|Author:||Finn RD, Bateman A|
|Number in seed:||15|
|Number in full:||355|
|Average length of the domain:||107.80 aa|
|Average identity of full alignment:||35 %|
|Average coverage of the sequence by the domain:||54.63 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||12|
|Download:||download the raw HMM for this family|
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