Circular Dichroism (CD) Spectroscopy
Monoclonal antibodies (mAbs) represent the most rapidly growing product class of therapeutic protein. Antibody characterization is a necessary activity during development and manufacturing to ensure the quality and safety of the products, which can be accomplished with a variety of analytical tools. Creative Biolabs is able to provide comprehensive mAb characterization and analysis services in terms of their structure, stability, aggregation, and heterogeneity by using different analytical techniques. Especially, the circular dichroism (CD) spectroscopy can be applied for high-order structure assessment, antibody stability measurement, aggregation monitoring, etc.
Introduction to Circular Dichroism (CD)
CD spectroscopy is a spectroscopic technique where the CD of molecules is measured over a range of wavelengths. CD is the difference in the adsorption of left-handed circularly polarized light (L-CPL) and right-handed circularly polarized light (R-CPL). CD spectroscopy is widely used in the study of large biological molecules. One of the major use is analyzing the secondary structure or conformation of macromolecules, particularly proteins.
On one hand, CD spectra in the far UV (180-250 nm) can be used to predict the percentages of different secondary structural elements (e.g., α-helix, β-sheet, etc.) in the structure of a protein because each of them has a distinctive spectral CD profile. As the secondary structure of proteins is sensitive to the environment (e.g., temperature, pH, excipients, ligands, denaturants, etc.), Far-UV CD can be used to observe how the secondary structure changes with environmental conditions. It can provide both kinetic and thermodynamic information.
On the other hand, CD spectra in the near-UV (250-300 nm) can be used to analyze the tertiary structure (e.g., tyrosine, tryptophan, phenylalanine residues, disulfide bridges) of the protein. It can provide information about changes in tertiary structure due to the alterations such as in formulation conditions, temperature, and storage conditions. Moreover, the CD can be used to determine whether a protein is folded. If not, the signals in the near-UV region will be nearly zero. Further, it can be used to compare and determine if two proteins have a similar structure, for instance, a mutant protein and a wild-type protein.
Antibody Analysis Services Provided by Creative Biolabs Based on CD Spectroscopy
- Determine whether the antibody is folded
- Characterize the secondary and tertiary structure of the antibody
- Characterize the structures of mAb produced by different expression systems
- Compare the structures of mutants and wild-type antibody
- Analyze antibody aggregation, as a complementary analytical tool for size-exclusion chromatography (SEC)
- Examine the stability of a mAb under stress, e.g., thermal stability, pH stability, and stability to denaturants
- Determine whether antibody-antigen interactions alter the conformation of the antibody
Features of Our Services
- Delivery of data with high sensitivity, accuracy, and resolution
- Broad expertise in recombinant mAbs and related products, such as biosimilars, fusion proteins, Fab and Fc fragments
- Customized services to meet all the specific needs of our clients
For high-order assessment, our biologic characterization group also provides other orthogonal techniques, including nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared (FTIR) spectroscopy, and fluorescence spectroscopy.
If you are interested in our services, please do not hesitate to contact us for more details.
For Research Use Only.