Creative BioMart is a well-known expert specializing in the application of advanced cell-free display technology to accelerate the release of protein engineering. With years of experience, we are able to provide covalent DNA display system service based on cell-free technology to precisely meet customer requirements.

Covalent DNA display is a new tool for directed evolution of proteins in vitro. The displayed protein is covalently linked to the cDNA it encodes. In this system, a linear DNA fragment library and a transcription/translation mixture in an in vitro water-in-oil emulsion compartment. A compartment contains a DNA molecule, and the DNA fragment encodes a fusion protein containing DNA-methyltransferase (M.Hae Ⅲ), which can form a covalent bond with the 5-fluorodeoxycytidine base at the end of the DNA fragment. This covalent DNA display technology provides a complete in vitro selection system based entirely on DNA-protein complexes.

Services

Creative BioMart provides a complete covalent DNA display platform based on P2 phage P2A endonuclease and in vitro compartmentalization. We have constructed P2A and single-chain antibody (scFvs) gene fusion proteins, which bind to the same DNA molecule that expresses it. A stable protein-DNA complex is produced through covalent linkage when coupling transcription and translation in vitro. In addition, we provide DNA-protein fusion libraries extracted from in vitro water-in-oil emulsion compartments and pass affinity screening for target antigens.

Covalent DNA display is a newly developed protein in vitro screening technology. The covalent DNA display technology we provide is widely used in DNA-protein fusion libraries to select DNA molecules that display proteins with desired binding properties. Its selectivity is as high as 150 times. Among them, M.Hae Ⅲ can be fused with small globular proteins, which is very suitable for generating combinatorial libraries and isolating new binding specificities.

Fig 1. Concept of covalent DNA display. (Bertschinger J, et al., 2007)

Features of Covalent DNA Display System

• Stability is a common advantage shared by all covalent DNA display methods. The nucleic acid component of the selection particle is robust in the presence of RNases, and the genotype-phenotype linkage should be able to withstand harsh biochemical conditions (e.g., the presence of denaturing agents or organic solvents, high or low salt concentrations, extreme pH) and/or elevated temperatures.
• Covalent DNA display circumvents the transformation of living cells. The mRNA and ribosome display system are only stable under certain conditions (high salt concentration, low temperature), which limits the experimental conditions that can be selected.
• A covalent linkage between DNA and the encoded polypeptide is achieved by using fusion proteins which contain the Hae III DNA. Simple and irreversible link between phenotype (protein) and genotype (genetic material).

Creative BioMart has been continuously developing cutting-edge cell-free display technology, and is committed to providing a flexible and efficient customized covalent DNA display system service. Based on the protein engineering platform, we have successfully constructed an impeccable cell-free surface display library of various types. We are proud to be able to screen and select proteins with the required characteristics from a large number of variants to best accelerate the research of life sciences. If you are interested in our services, please do not hesitate to contact us for more information.

References

1. Bertschinger J, Neri D. (2004) Covalent DNA display as a novel tool for directed evolution of proteins in vitro. Protein Eng Des Sel. 17(9): 699-707.
2. Bertschinger J, Grabulovski D, Neri D. (2007) Selection of single domain binding proteins by covalent DNA display. Protein Eng Des Sel. 20(2): 57-68.

• In Vitro Compartmentalization Displays Service
• mRNA Displays Service
• Noncovalent DNA Displays Service
• Ribosome Displays Service