|Secreted proteins typically have an N-terminal hydrophobic signal sequence which facilitates their translocation into the endoplasmic reticulum (ER). Many secreted proteins are N-glycosylated on Asn-X-Ser/Thr motif in the ER, and disulfide bond formation is also accomplished in the ER. N- or C-terminal 8xHis tag can be provided to facilitate target protein affinity purification and immunodetection. Secreted proteins can be also expressed in fusion with MBP tag, which could improve protein solubility. We offer a variety of vectors to facilitate these processes.
|Mix and match features provided in the vectors
pAB-bee™ encodes powerful signal sequence
pAB-bee™-8xHis encodes powerful signal sequence and His-tag, which facilitates purification by immobilized metal affinity chromatography
ProFold™-ER1 provides Calreticulin, a major molecular chaperone facilitating glycoprotein folding, and PDI which facilitates the correct formation of disulfide bonds
pAB-6xHis-MBP can provide C-terminal MBP tag to reduce protein aggregation
|The above features can be mixed and matched in various combinations, while supporting a high level of target protein expression. They can also be combined with "plain vectors" which only provide a high level of protein expression (pVL1393, ProEasy™, ProGreen™, ProFold™-0). A plasmid transfer vector is always combined with a baculovirus DNA vector, and some combinations are available as Kits. Click on TECHNOLOGY for more information on baculovirus expression system. Go to BACULOVIRUS TUTORIAL for simple on-line instructions on baculovirus transfection, propagation of recombinant baculoviruses and recombinant baculovirus protein expression studies.
|1.Target protein has a large ectodomain, a weak signal sequence, is known to be glycosylated, and has multiple cysteines. Insert gene encoding mature target protein into pAB-bee™ plasmid vector in lieu of the powerful insect signal sequence and co-transfect with ProFold™-ER1 linearized baculovirus DNA.
|2.Target protein has no N-terminal signal sequence. Its ectodomain is known to be glycosylated and has multiple cysteines. Insert gene encoding entire ORF of the target protein into pVL1393 plasmid vector and co-transfect with ProFold™-ER1 linearized baculovirus DNA.
|3.Target protein has a strong N-terminal signal sequence. Its ectodomain is known to be glycosylated and has multiple cysteines. Insert gene encoding the entire ORF of the target protein into pVL1393 plasmid vector and co-transfect with ProFold™-ER1 linearized baculovirus DNA.
|Signal sequence in secreted proteins
|A hydrophobic signal peptide sequence which is followed by a signal peptidase cleavage site is often present on the N-terminus of transmembrane proteins. However, some signal peptides are less efficient than others. The cleavage sites also may differ in their efficiency. You can evaluate your target protein for the presence of a signal peptide and its cleavage site using the TargetP program (Emanuelson O. et al., J.Mol.Biol., 300: 1005-10016, 2000). The program is user friendly and is available at http://www.cbs.dtu.dk/services/TargetP/
|An inefficient signal peptide or its incomplete cleavage is likely to result in the misfolding of a significant portion of the expressed protein and in an accumulation of inclusion bodies or protein degradation. In such cases the inefficient native target protein signal sequence can be substituted for a signal sequence which is optimized for a particular protein expression system.
|*Go to PRODUCTS to order online. Alternatively, email an order as pdf attachment to email@example.com, or send it by Fax to 1-760-454-2465 or call 1-866-683-2867 to order by phone.
|If you have not worked with baculovirus expression system, also referred to as baculovirus expression vector system or BEVS, you can get a quick update at TECHNOLOGY. Go to BACULOVIRUS TUTORIAL for simple on-line instructions on baculovirus transfection, propagation of recombinant baculoviruses and recombinant baculovirus protein expression studies.
|Click on PRODUCTS to view the entire list of recombinant baculovirus-related products.