1272 results about "Expression protein" patented technology

Compositions, methods, and kits are provided for efficiently generating and screening a library of highly diverse protein complexes for their ability to bind to other proteins or oligonucleotide sequences. In one aspect of the invention, a library of expression vectors is provided for expressing the library of protein complexes. The library comprises a first nucleotide sequence encoding a first polypeptide subunit; and a second nucleotide sequence encoding a second polypeptide subunit. The first and second nucleotide sequences each independently varies within the library of expression vectors. In addition, the first and second polypeptide subunit are expressed as separate proteins which self-assemble to form a protein complex, such as a double-chain antibody fragment (dcFv or Fab) and a fully assembled antibody, in cells into which the library of expression vectors are introduced. The library of expression vectors can be efficiently generated in yeast cells through homologous recombination; and the encoded proteins complexes with high binding affinity to their target molecule can be selected by high throughput screening in vivo or in vitro.

Disclosed are useful constructs and methods for the expression of proteins using primary translation products that are processed within a recombinant host cell. Constructs comprising a single open reading frame (sORF) are described for protein expression including expression of multiple polypeptides. A primary translation product (a pro-protein or a polyprotein) contains polypeptides such as inteins or hedgehog family auto-processing domains, or variants thereof, inserted in frame between multiple protein subunits of interest. The primary product can also contain cleavage sequences such as other proteolytic cleavage or protease recognition sites, or signal peptides which contain recognition sequences for signal peptidases, separating at least two of the multiple protein subunits. The sequences of the inserted auto-processing polypeptides or cleavage sites can be manipulated to enhance the efficiency of expression of the separate multiple protein subunits. Also disclosed are independent aspects of conducting efficient expression, secretion, and/or multimeric assembly of proteins such as immunoglobulins. Where the polyprotein contains immunoglobulin heavy and light chain segments or fragments capable of antigen recognition, in an embodiment a selectable stoichiometric ratio is at least two copies of a light chain segment per heavy chain segment, with the result that the production of properly folded and assembled functional antibody is made. Modified signal peptides, including such from immunoglobulin light chains, are described.

Bacteria which co-express protease inhibitors and protease sensitive therapeutic agents, which are surface displayed, secreted and/or released and result in their localized production and maintenance within a target tissue and inactivation outside of the target tissue, thereby increasing therapeutic activity and reducing the systemic toxicity. The bacteria may be attenuated, non-pathogenic, low pathogenic or a probiotic. Protease sensitivity may be further accomplished by engineering protease degradation sites within the therapeutic agents, further enhancing the inactivation outside of the target tissue while retaining activity within the target tissue through co-expression of a protease inhibitor. Novel chimeric proteins secreted by bacteria, including chimeric toxins targeted to neoplastic cells, tumor matrix cells and cells of the immune system, and combination therapies of these protease inhibitor:chimeric toxin-expressing bacteria together with small-molecule and biologic agents are also described. Non-conjugative bacteria limiting exchange of genetic material, and antibody resistant bacteria are also provided.

The invention provides a DNA molecule comprising a multicistronic transcription unit coding for i) a selectable marker polypeptide functional in a eukaryotic host cell, and for ii) a polypeptide of interest, the polypeptide of interest having a translation initiation sequence separate from that of the selectable marker polypeptide, characterized in that the coding sequence for the polypeptide of interest is downstream from the coding sequence for the selectable marker in said multicistronic transcription unit, and the nucleic acid sequence coding for the selectable marker polypeptide comprises a mutation that decreases the translation efficiency of the selectable marker in a eukaryotic host cell. The invention also provides methods for obtaining host cells expressing a polypeptide of interest, said host cells comprising the DNA molecules of the invention. The invention further provides the production of polypeptides of interest, comprising culturing host cells comprising the DNA molecules according to the invention.

The present invention relates to methods and tools for producing large quantities of gamma-carboxylated protein comprising: (i) culturing a cell adapted to express a protein which requires gamma-carboxylation and γ-glutamyl carboxylase in a ratio of at least 10:1, under conditions suitable for expression of both proteins, and (ii) isolating gamma-carboxylated protein.

The present invention relates to a method for display of proteinson spore surface and a method for improving protein with rapidity using the same, which comprises the steps of (i) preparing a vector for spore surface display comprising a gene construct containing a gene encoding spore coat protein and a gene encoding a protein of interest, wherein, when expressed, the gene construct expresses a fusion protein between the spore coat protein and the protein of interest, (ii) transforming a host cell with the vector for spore surface display; (iii) displaying the protein of interest on a surface of a spore of the host cell; and (iv) recovering the spore displaying on its surface the protein of interest.

The invention belongs to the technical field of biological vaccine preparation, and particularly relates to a porcine epidemic diarrhea (PED) recombinant baculovirus gene engineering subunit vaccine, a preparation method and an application thereof. According to the present invention, S1 gene and M gene of the current new PEDV epidemic strain are selected as reference sequences, a baculovirus expression system is adopted to express S1 protein or partial S1 protein and M protein, and the obtained recombinant protein is prepared into a subunit vaccine for effectively controlling PED occurrence; with the PED recombinant baculovirus gene engineering subunit vaccine produced by using the method, the defect of the current PEDV traditional vaccine is solved; and the PED recombinant baculovirus gene engineering subunit vaccine can be used for prevention and treatment of PEDV infections and related diseases caused by PEDV, and can further be used for preparation of coating antigen of PEDV detection antibody ELISA kits.

The invention discloses a subunit coronavirus vaccine for dimerization-based receptor binding domains and belongs to the technical field of medicine. A baculovirus expresses RBD (receptor binding domain (E367-Y606) of MERS-CoV (middle east respiratory syndrome coronavirus) protein and RBD (R294-F515) of SARS-CoV (severe acute respiratory syndrome coronavirus) in insect cells, the RBDs may form a dimer through cysteine residue at 603 of S (spike) protein or form a dimer through cysteine residue at 512 of the S protein, and purified RBD protein dimer and monomer are used respectively to immunize Bald/c mice. The dimerized RBDs have the advantages that the defect that RBD monomers have poor immunogenicity is overcome and the generation of neutralizing antibodies in against MERS-CoV is increased greatly.

The present invention relates to a method of selecting a protein variant having reduced immunogenicity as compared with the parent protein. This method includes the steps of screening a random peptide display package library with antibodies raised against any protein of interest, sequencing the amino acid sequence of the antibody binding peptides, or the DNA sequence encoding the antibody binding peptides, identifying epitope patterns of a protein by sequence alignment of the reactive peptide sequence, localization of epitope patterns on the primary 3-dimensional structure of the parent protein, defining an epitope area including amino acids situated within 5 Å from the epitope amino acids, and affecting antibody binding to the epitope, changing the localized epitope patterns, or amino acids defining the epitope area of the parent protein by genetic engineering mutations of a DNA sequence encoding the parent protein without impairing functionality of the protein using the emerging epitode database for eliminating amino acid substitutions creating new or duplicating existing epitope patterns, introducing the mutated DNA sequence into a suitable host, culturing the host and expressing the protein variant, and evaluating the immunogenicity of the protein variant using the parent protein as reference. The invention further relates to the protein variant and its use, as well as to a method for producing said protein variant.

The invention discloses a recombinant human collagen and an application thereof. An amino acid sequence of the protein is shown as SEQ ID NO. 3, the nucleotide sequence of the protein-coding gene is shown as SEQ ID NO. 1. The recombinant human collagen of the invention has very good hydrophilicity and stability, and the amino acid composition thereof is 100% identical to the corresponding amino acid sequence of the natural collagen, and the amount of expressed protein can account for about 25% of the total protein of the thalline, per milliliter of the bacteria liquid precipitate contains 0.25mg of the target protein, and the production cost is very low and the cycle is short. The prepared collagen is applied to the human body without immunological rejection and allergic reaction, and canbe widely applied to the biomedicine and cosmetics industries.

The present invention relates to methods and compositions for chemically defined media for growth of mammalian cells for production of commercially useful amounts of expressed proteins.

The invention discloses a novel coronavirus N-S dominant epitope fusion protein, a preparation method, application, an expression protein, a microorganism, application and a kit, and belongs to the technical field of genetic engineering. The novel coronavirus N-S dominant epitope fusion protein is a novel coronavirus N protein and S protein dominant epitope fusion protein. The preparation method comprises the following steps: firstly, constructing a fusion expression antigen by an S protein dominant epitope segment antigen and an N protein dominant epitope segment antigen of a novel coronavirus; then removing rare codons through gene optimization to obtain an optimized gene sequence; and finally, obtaining a soluble high-activity antigen with efficient expression. The novel coronavirus N-Sdominant epitope fusion protein disclosed by the invention has soluble expression, high yield, high purity and good activity, and is suitable for accurate diagnosis and detection of patients with thenovel coronavirus.

The present invention relates to the production of proteins in a cell or host cell. The invention uses a TRAnscription Pause (TRAP) sequence to enhance a protein expression characteristic of a protein expression unit. The TRAP sequence is thought to prevent, at least in part, formation of antisense RNA or to, at least in part, prevent transcription to enter the protein expression unit. In one embodiment, the invention provides a method for expression of at least one protein of interest in a cell comprising providing the cell with at least one protein expression unit that comprises a promoter functionally linked to an open reading frame encoding at least one protein of interest, characterized in that the protein expression unit further comprises at least one TRAP sequence and wherein the TRAP sequence is functionally located downstream of the open reading frame and at least in part prevents formation of antisense RNA. In another embodiment, the TRAP sequence is functionally located upstream of the promoter and at least in part prevents transcription to enter the expression unit. Preferably, the expression protein unit further comprises at least one STabilizing Anti-Repressor sequence.

The invention discloses a biological product for preventing novel coronavirus (COVID-19). The biological product can be a gene vaccine or gene medicine, wherein the gene vaccine adopts a human type-5adenovirus with deletion of E1 and E3 genes as a vector for carrying an S1 protein antigen for expressing a Spike S1 subunit of the novel coronaviruses or simultaneously carrying an S1 expression protein antigen and N protein antigen. Through in-vivo expression of antigen proteins, the immune reaction of a body upon the novel coronavirus can be stimulated, and the effect of preventing infection and propagation of the novel coronavirus.

The invention discloses a method of determining protease activity, in real time, using fluorescence polarization technology. In particular, the invention provides vectors and a method for their use, which expresses uncharacterized proteins conjugated to a fluorescence tag, which binds specifically to a fluorescent ligand. Cleavage of the recombinant protein results in a fragment of the expressed peptide and results in a change in fluorescence polarization of the fluorophore. The rate of change in fluorescence polarization can be measured in real time and is equivalent to the rate of protease cleavage.

The invention relates to an enzyme-linked immunosorbent assay (ELISA) kit for duck hepatitis virus type-I serum antibody and relates to a test method and application of the kit. The kit comprises an enzyme label plate coated by the recombinant VP1 (virus protein) protein, a rabbit anti-duck IgY antibody marked by horseradish peroxidase, a TMB substrate colour reagent, a positive serum, a negative serum and a kit specification. In the invention, by adopting the polymerase chain reaction, the VP1 genes are amplified from the DHV-1genome and the VP1 gene-containing recombinant expression plasmid pET32a-VP1 is constructed; the plasmid is transferred to host cells BL21 (DE3), and the in-vitro expression VP1 protein is purified by a nickel column and then used as the antigen; the enzyme-linked immunosorbent assay kit is established; the positive serum is the standard positive serum of duck hepatitis virus type-I and the negative control is the standard negative serum of duck. The test kit has the advantages of strong specificity, high sensitivity, simple operation, easy large-scale popularization and application, very important application value in diagnosis of duck hepatitis virus type-I, survey of epidemiology and immunization survey and the like.

An improved system for large scale production of proteins and/or polypeptides in cell culture is provided. In accordance with the present invention, cells expressing the protein or polypeptide of interest are grown in media that comprise a glycolysis-inhibiting substance. Additionally and/or alternatively, cells expressing the protein or polypeptide of interest are grown in media in which glutamine is limited. The use of such a system allows high levels of protein or polypeptide production and lessens accumulation of undesirable metabolic waste products such as lactate. Proteins and polypeptides expressed in accordance with the present invention may be advantageously used in the preparation of pharmaceutical, immunogenic, agricultural or other commercial compositions.

The present invention discloses recombinant soluble human tumore necrosis factor related death inducing ligand and its preparation process and application in preparing antitumor medicine. The present invention adopts human tonsil tissue mRNA as template to amplify TRAIL coding sequence, constitute engineering colibacillus for expressing rhsTRAIL and engineering saccharomycete, establish the rhsTRAIL engineering colibacillus fermentation, occlusion body washing and destination protein purification process and the engineering saccharomycete and destination protein purification process separately, and obtain pure rhsTRAIL product, which has molecular weight of 19.6-24 KD and exists in both monomer and dimmer. The rhsTRAIL can induce death of several kinds of cancer cells outside body, inhibit amplification of liver cancer cell in tumor loading mouse obviously and kill tumor cell selectively, so that it may be used in preparing effective antitumor medicine.