LC-MS/MS

Liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS) is a versatile analytical technique for protein research. Creative BioMart Nanocage has accumulated extensive experience in using LC-MS/MS to identify and analyze protein nanocages. As protein nanocages are huge molecules composed of multiple subunits, we primarily utilize the bottom-up strategy. Briefly, protein nanocages are first digested by enzymes into peptides. High-performance liquid chromatography then separates the peptides with high resolution, and MS/MS gives structural information about peptides. MS/MS typically consists of two sets of ionization and detection modules. The first MS detector (MS1) ionizes molecules flowing out of the LC column and separates them according to their mass-to-charge ratios (m/z). Soft ionization technique, electrospray ionization, is adopted. Between MS1 and the second MS detector (MS2), there is a collision cell where the ions from MS 1 are split into smaller production ions in a predictable manner. Peptide bonds are the main cleavage sites in this site, and a series of b and y ions are generated. The MS2 detector then determines the m/z of these production ions. According to the b and y ion m/z values, the sequence of the precurson ion from MS1 can be known.

Fig 1. Principle of Bottom-up LC-MS/MS Analysis

Creative BioMart Nanocage provides highly accurate and client-friendly LC-MS/MS service for all types of protein nanocages. We accept different types of samples, such as protein in solutions, lyophilized protein samples, and cells expressing target protein nanocages. In terms of sample preparation, we offer protein desalting, protein concentration, and protein purification through gel electrophoresis services. We have a wide selection of enzymes to digest protein nanocages, including trypsin, Lys C, Lys N, Glu C, Asp N, chymotrypsin, Arg C, and CNBr. Protein nanocage digestion strategy will be tailored according to the specific characterization need of our clients.

Our LC-MS/MS service can help clients achieve multiple research aims.

• Verification of the primary sequence of protein nanocage subunits. A correct primary sequence of protein nanocage subunit is the foundation for the expected conformation and bioactivity.
• For protein nanocages made up of multiple type of subunits, we offer ratio determination of each type of subunit.
• Obtaining post-translational modification sites and types. For example, the glycosylation sites on eukaryotic cells expressed virus-like particles. Post-translational modifications are likely to affect the thermal stability, pH stability, and folding of protein nanocages.
• Identification of protein degradation, such as deamidation and oxidation. Degradation of protein nanocages may lead to changes in structure and bioactivity. Suggestions on how to inhibit the identified degradations are also offered by our protein nanocage scientist.
• Location of disulfate bonds, verification of the theoretical disulfate bonds, and identification of the incorrect disulfate bonds.

If you are interested in our LC-MS/MS service, please do not hesitate to contact us through online inquiry to get more information. We guarantee prompt feedbacks and high quality of our LC-MS/MS service. We are looking forward to hearing from you.