Recombinant Proteins


Structural Biology

  Address:Changshu High-tech Industrial Development district, Suzhou, Jiangsu Province 1001, Building 6, No.88 Xian Shi Road

    Recombinant proteins are obtained by applying recombinant DNA or RNA techniques. Recombinant proteins include various receptors, cytokines, growth factors, transcription factors, immune checkpoints, hormones, enzymes, viral antigens, antibody fragments, prodots, etc. They can be used in both commercial fields and scientific research such as new drug discovery, antibody preparation, ELISA, immunoassay.

        ReadCrystal established advanced and mature protein expression technology and protein purification system. We can provide protein products with high purity, high quality and excellent biological activity according to different needs of customers.
Service Content
Soluble Protein
Proteins which are usually very small and soluble in water or other solvents in the cytoplasm. ReadCrystal has mature and rich experience in soluble protein expression and purification. We can provide you with customized one-stop protein expression and purification services.
Inclusion Body
Inclusion body is dense, insoluble protein particles encapsulated by a membrane that forms when an exogenous gene is expressed in a prokaryotic cell. The protein within the inclusion body is aggregated in an unfolded state and is not biologically active.
Membrane Proteins
Membrane proteins are common proteins that are part of biological membranes, including glycoproteins, carrier proteins and enzymes. They are hotspots in scientific research and ideal target for drug discovery research. We can provide quickly and in sufficient quantities membrane proteins for you by overexpression techniques.
Secreted Proteins
Secreted proteins are exogenous genes that are expressed inside the cell and then secreted outside the cell, including cytokines, complement, degrading enzymes, peptide hormones, immunoglobulins, etc in the blood and extracellular matrix.
Service Flow
1. Plasmid Construction
Based on the gene coding sequence corresponding to your given protein, we will synthesize a gene fragment suitable for protein expression. For the selection of the gene vector and the addition of the purification label, we will review the references extensively and listen to your specific needs to propose the most suitable solution base on the experience of our technical team.

Available purification labels, vectors include but are not limited to the following

2.Expression Systems
We usually used E.coli e.g. BL21, Rosetta. Other available bacterial hosts include Bacillus subtilis, Streptomyces. 
We have a wide range of expression vectors and strains, and we are constantly optimizing expression conditions to achieve the best results.

Suitable for Glycosylation-free, simple modified recombinant proteins, isotope-tagged proteins

Advantages •     proven technology, wide application, low cost
                    •     Fast multiplication, high expression, shortened experiment time
                    •     High resistance to contamination
                    •     relatively simple isolation and purification of expression products, good stability
                    •     Clear genetic background
Divided into brewer's yeast expression systems and methanolic nutritional yeast expression systems, the latter (e.g. Pichia) are the most widely used yeast expression system.
Using our unique combination of vector and host, we can greatly improve the quality and quantity of recombinant protein expression and shorten the experimental cycle.

Suitable for secreted proteins, recombinant proteins with simple modifications, isotope-tagged proteins, etc.

Advantages •     Short cycle time, low cost and high efficiency
                    •     Ability to process proteins, post-translational modifications
                    •     Can be used to express secreted proteins
                    •     Endotoxin free

Also known as the baculovirus expression vector system (BEVS), it is the closest expression system to mammalian cells.
Our multi-system, multi-vector expression strategy can overcome the difficulties of traditional expression systems and maximise the efficiency and quality of expression.

Suitable for viral vaccines, signalling molecules, cytokines, kinases, etc.

Advantages •      High efficient expression of exogenous genes
                    •      Glycosylation and extensive post-translational modifications
                    •      Easy to screen recombinant viruses
                    •      Partially protein folding
                    •      Endotoxin free
Mammalian expression systems provide the closest post-translational modifications, protein folding and polymerization of recombinant human proteins to their natural state, with the necessary spatial structure and modifications for active proteins.
We established unique combination of mammalian cell expression vectors and transfection methods which allows us to optimize the expression conditions by selecting a customized solution for the target protein, thereby significantly increasing expression and shortening the experimental time.

Suitable for complex eukaryotic proteins

Advantages •       Higher expression levels
                    •       Correct protein folding
                    •       Secreted proteins expression
                    •       Accurate post-translational modifications
                    •       Good growth in adherent or suspension culture, easy to scale up
                    •       Endotoxin free
Available expression hosts include but are not limited to the following
3.Protein Purification
Investigate the characteristics of target proteins and main impurities and design the most appropriate protein purification protocol based on the origin, characteristics (molecular size, isoelectric point) and stability (tolerance to temperature, extreme pH, proteases, oxygen and metal ions, etc.) of the protein.
High pressure and low temperature homogenization
After harvesting, the cells are massively fragmented by liquid shearing to harvest cellular material for subsequent purification
Hydrophobic Interaction Chromatography
A chromatographic method of purification based on the hydrophobic nature of biomolecules. When the ionic strength of the buffer is high, the hydrophobic force between the protein and the chromatographic medium is enhanced and adsorption is achieved. When the ionic strength of the mobile phase is reduced, the hydrophobic interaction between the protein molecules and the chromatography medium is weakened and the target protein can be eluted and collected.
Gel filtration chromatography
Also know as size exclusion chromatography. It is based on the difference in the relative molecular mass of the components of the sample being separated. The operating conditions are relatively mild and do not require organic solvents.
Ion exchange chromatography
Different proteins have different isoelectric points(pl). At different pH conditions, proteins will carry different charges. Different ion exchange columns can be selected according to the different surface charges of proteins at different pH conditions. Ion exchange chromatography is often used in combination with other purification methods in protein purification step.
Affinity chromatography
Protein separation and purification is achieved through specific interactions between biomolecules, and the ligands on the affinity adsorbent selectively adsorb substances that can bind to them. Because of its high selectivity, purity and speed, affinity chromatography is usually used as the first capture step to remove most of the impurity proteins.