Structural polyprotein Recombinant Protein | SFVgp2 recombinant protein
Recombinant Semliki forest virus Structural polyprotein
NCBI and Uniprot Product Information
Uniprot Description
Function: Capsid protein possesses a protease activity that results in its autocatalytic cleavage from the nascent structural protein. Following its self-cleavage, the capsid protein transiently associates with ribosomes, and within several minutes the protein binds to viral RNA and rapidly assembles into icosaedric core particles. The resulting nucleocapsid eventually associates with the cytoplasmic domain of E2 at the cell membrane, leading to budding and formation of mature virions. New virions attach to target cells, and after clathrin-mediated endocytosis their membrane fuses with the host endosomal membrane. This leads to the release of the nucleocapsid into the cytoplasm, followed by an uncoating event necessary for the genomic RNA to become accessible. The uncoating might be triggered by the interaction of capsid proteins with ribosomes. Binding of ribosomes would release the genomic RNA since the same region is genomic RNA-binding and ribosome-binding. Ref.13 Ref.14 Ref.15 Ref.21E3 protein's function is unknown. Ref.13 Ref.14 Ref.15 Ref.21E2 is responsible for viral attachment to target host cell, by binding to the cell receptor. Synthesized as a p62 precursor which is processed by furin at the cell membrane just before virion budding, giving rise to E2-E1 heterodimer. The p62-E1 heterodimer is stable, whereas E2-E1 is unstable and dissociate at low pH. p62 is processed at the last step, presumably to avoid E1 fusion activation before its final export to cell surface. E2 C-terminus contains a transitory transmembrane that would be disrupted by palmitoylation, resulting in reorientation of the C-terminal tail from lumenal to cytoplasmic side. This step is critical since E2 C-terminus is involved in budding by interacting with capsid proteins. This release of E2 C-terminus in cytoplasm occurs lately in protein export, and precludes premature assembly of particles at the endoplasmic reticulum membrane. Ref.13 Ref.14 Ref.15 Ref.216K is a constitutive membrane protein involved in virus glycoprotein processing, cell permeabilization, and the budding of viral particles. Disrupts the calcium homeostasis of the cell, probably at the endoplasmic reticulum level. This leads to cytoplasmic calcium elevation. Because of its lipophilic properties, the 6K protein is postulated to influence the selection of lipids that interact with the transmembrane domains of the glycoproteins, which, in turn, affects the deformability of the bilayer required for the extreme curvature that occurs as budding proceeds. Present in low amount in virions, about 3% compared to viral glycoproteins. Ref.13 Ref.14 Ref.15 Ref.21E1 is a class II viral fusion protein. Fusion activity is inactive as long as E1 is bound to E2 in mature virion. After virus attachment to target cell and endocytosis, acidification of the endosome would induce dissociation of E1/E2 heterodimer and concomitant trimerization of the E1 subunits. This E1 trimer is fusion active, and promotes release of viral nucleocapsid in cytoplasm after endosome and viral membrane fusion. Efficient fusion requires the presence of cholesterol and sphingolipid in the target membrane. Fusion is optimal at levels of about 1 molecule of cholesterol per 2 molecules of phospholipids, and is specific for sterols containing a 3-beta-hydroxyl group. Ref.13 Ref.14 Ref.15 Ref.21
Catalytic activity: Autocatalytic release of the core protein from the N-terminus of the togavirus structural polyprotein by hydrolysis of a -Trp-|-Ser- bond.
Subunit structure: p62 and E1 form a heterodimer shortly after synthesis. Processing of p62 into E2 and E3 results in a heterodimer of E2 and E1. Spike at virion surface are constituted of three E2-E1 heterodimers. After target cell attachment and endocytosis, E1 change conformation to form homotrimers.
Subcellular location: Capsid protein: Virion
By similarity. Host cytoplasm
By similarity. p62: Virion membrane; Single-pass type I membrane protein
By similarity. Host cell membrane; Single-pass type I membrane protein
By similarity. E2 envelope glycoprotein: Virion membrane; Single-pass type I membrane protein
By similarity. Host cell membrane; Single-pass type I membrane protein
By similarity. E1 envelope glycoprotein: Virion membrane; Single-pass type I membrane protein
By similarity. Host cell membrane; Single-pass type I membrane protein
By similarity. 6K protein: Host cell membrane; Multi-pass membrane protein
By similarity. Virion membrane; Multi-pass membrane protein
By similarity.
Post-translational modification: Specific enzymatic cleavages in vivo yield mature proteins. Capsid protein is auto-cleaved during polyprotein translation, unmasking p62 signal peptide. The remaining polyprotein is then targeted to the endoplasmic reticulum, where host signal peptidase cleaves it into p62, 6K and E1 proteins. p62 is further processed to mature E3 and E2 by host furin in trans-Golgi vesicle. Protein processing process takes about 30 minutes at physiologic temperatures. The folding of the p62/6K/E1 precursor requires the formation of intrachain disulfide bonds and has been shown to involve a transient covalent interaction between the nascent and newly synthesized heterodimer and the host-cell chaperones, P4HB/PDI and PDIA3/ERp57. The folding pathway also includes non covalent interaction with human CANX/calnexin and CALR/calreticulin. Ref.8 Ref.10 Ref.12 Ref.17 Ref.20Envelope E1, E2 and E3 proteins are N-glycosylated. Ref.25E2 is palmitoylated via thioester bonds. These palmitoylations may induce disruption of the C-terminus transmembrane. This would result in the reorientation of E2 c-terminus from lumenal to cytoplasmic side. 6K protein is also palmitoylated with about four covalently bound fatty acids per molecule. E1 is stearoylated. Ref.9
Miscellaneous: The mature virion nucleocapsid consists of 240 copies of the capsid protein. 80 spike trimers of E1 and E2 are present at the surface of mature virion. They project about 100 Angstroms from the outer surface and are located at the local and strict three fold axis of the icosaedral lattice. The glycoproteins splay out to form a protein shell or skirt covering most of the outer surface of the membrane bilayer.Structural polyprotein is translated from a subgenomic RNA synthesized during togavirus replication.
Sequence similarities: Contains 1 peptidase S3 domain.
Research Articles on SFVgp2
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Product Notes
The SFVgp2 c (Catalog #AAA1252148) is a Recombinant Protein produced from E Coli or Yeast or Baculovirus or Mammalian Cell and is intended for research purposes only. The product is available for immediate purchase. The immunogen sequence is 816-1253. The amino acid sequence is listed below: YEHSTVMPNV VGFPYKAHIE RPGYSPLTLQ MQVVETSLEP TLNLEYITCE YKTVVPSPYV KCCGASECST KEKPDYQCKV YTGVYPFMWG GAYCFCDSEN TQLSEAYVDR SDVCRHDHAS AYKAHTASLK AKVRVMYGNV NQTVDVYVNG DHAVTIGGTQ FIFGPLSSAW TPFDNKIVVY KDEVFNQDFP PYGSGQPGRF GDIQSRTVES NDLYANTALK LARPSPGMVH VPYTQTPSGF KYWLKEKGTA LNTKAPFGCQ IKTNPVRAMN CAVGNIPVSM NLPDSAFTRI VEAPTIIDLT CTVATCTHSS DFGGVLTLTY KTNKNGDCSV HSHSNVATLQ EATAKVKTAG KVTLHFSTAS ASPSFVVSLC SARATCSASC EPPKDHIVPY AASHSNVVFP DMSGTALSWV QKISGGLGAF AIGAILVLVV VTCIGLRR. It is sometimes possible for the material contained within the vial of "Structural polyprotein, Recombinant Protein" to become dispersed throughout the inside of the vial, particularly around the seal of said vial, during shipment and storage. We always suggest centrifuging these vials to consolidate all of the liquid away from the lid and to the bottom of the vial prior to opening. Please be advised that certain products may require dry ice for shipping and that, if this is the case, an additional dry ice fee may also be required.Precautions
All products in the AAA Biotech catalog are strictly for research-use only, and are absolutely not suitable for use in any sort of medical, therapeutic, prophylactic, in-vivo, or diagnostic capacity. By purchasing a product from AAA Biotech, you are explicitly certifying that said products will be properly tested and used in line with industry standard. AAA Biotech and its authorized distribution partners reserve the right to refuse to fulfill any order if we have any indication that a purchaser may be intending to use a product outside of our accepted criteria.Disclaimer
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