Welcome to CD BioSciences

Cysteine-based VLP Modification Service

CD BioSciences is a leading global provider of custom services, working closely with clients and experts in the construction of chimeric virus-like particles (cVLPs) by chemical conjugation methods. Our experienced scientists specialize in a sophisticated VLPlantTM platform and are happy to meet each specific client requirement to provide the most appropriate solution to provide you with high quality and on-time delivery of cVLPs construct results.

Overview of Cysteine-based Modifications


Cysteine, abbreviated as Cys or C, is a non-essential amino acid containing sulfur. It is synthesized in animals via methionine and serine and has a mitigating effect on the repair of radiation damage to the body, as well as a wide range of detoxifying effects. Enzymes involved in metabolism and signaling are regulated by post-translational modifications that affect catalytic activity, turnover rate and localization to subcellular sites. The most common method of post-translational modification regulation is phosphorylation/dephosphorylation, in addition to a unique method of post-translational modification - multifunctional redox modification of cysteine residues. Although it does not constitute a high proportion of the amino acid sequence of proteins, cysteine is widely used for selective modification of proteins due to its remarkable nucleophilic and redox properties and ease of modification. Therefore, cysteine is a multifunctional amino acid that It plays a key role in different organic reactions.

  • Features of Cysteine-based Modifications
    The free sulfhydryl group of cysteine makes it easy to form disulfide bonds spontaneously with other sulfhydryl-containing ligands under oxidizing conditions. The more common methods for cysteine-based protein modification include disulfide bond exchange reactions, alkylation, and Michell addition reactions with maleimide or vinyl sulfone. The Michael addition reactions of maleimide and vinyl sulfone with sulfhydryl groups are very classical reactions for modifying sulfhydryl groups and are the better methods for modifying cysteines in proteins.
  • Cysteine-based VLPs Modifications
    Cysteine is the most commonly used reactive amino acid residue that can be presented on the surface of VLPs by natural presentation or mutation. However, disulfide bonds can also be easily reduced if the ligand is not an ideal surface attachment for VLPs. At pH values between 6.5 and 7.5, a range of compounds based on maleimide are able to form irreversible thioether attachments to cysteine residues. This attachment method has been widely used to attach fluorescent probes, peptides and proteins to the surface of VLPs.

Our Services

As the world's leading custom service provider, CD BioSciences provides customers with VLP modification services based on cysteine-modified chemical conjugation methods. If you are interested in our services, you can contact us for more details., we are happy to hear from you and look forward to working with you.

Why Choose CD BioSciences

Why Choose CD BioSciences

We have a long history of providing VLPs modification services to our global clients and are adept at solving the difficulties and challenges encountered during experiments.

We are in constant contact with our customers to discuss issues encountered during the construction of cVLPs in a timely manner.

High Quality
We have the ability and confidence to employ the best experimental protocols to meet your needs for rapid and accurate construction of cVLPs.

For Research Use Only.

Online Inquiry