There are two common methods for peptide sequence analysis: database search and de novo sequencing. Database search requires searching a known/given database to identify peptide sequences. However, due to insufficient databases for some species, many new or active peptides cannot be matched in the data. De novo peptide sequencing can solve this problem. It refers to the process of using tandem mass spectrometry (MS/MS) to obtain the amino acid sequence of peptides without the help of a sequence database. The advantage is that sequence analysis can be performed regardless of the presence of a theoretical database or whether the peptide is new or unknown.
The basic principle of de novo sequencing is to calculate the mass of amino acid residues on the peptide chain by using the mass difference between two fragment ions. The implementation of de novo peptide sequencing is closely related to the development of mass spectrometry technology. In recent years, the mass resolution of mass spectrometry has improved by several orders of magnitude, especially the significant improvement in high-precision mass spectrometry performance, providing a strong foundation for peptide sequence analysis.
Schematic diagram of high-quality spectral theoretical fragment ions for de novo peptide sequencing
Bioinformatics company uses Thermo's latest Obitrap Fusion Lumos mass spectrometer combined with Nano-LC nanoflow chromatography technology to provide mass spectrometry-based de novo peptide sequencing services for peptide sequence analysis. Bioinformatics company uses Thermo's latest Obitrap Fusion Lumos mass spectrometer to perform sequence analysis of peptide samples. The Obitrap Fusion Lumos mass spectrometer has the highest resolution and sensitivity, ensuring the sensitivity of low-abundance peptide fragment identification; meanwhile, the combination of HCD and ETD modes during peptide fragmentation ensures the integrity of peptide fragments. After obtaining the original mass spectrometry data, the de novo sequencing method is used to deduce the peptide sequence.
Sample preparation recommendations:
Prepare at least 20 ug of sample whenever possible, either in solution or lyophilized powder. If it is a solution sample, ensure the buffer does not contain high salt, SDS, or other detergents.
**You can consult the technical staff of Bioinformatics company for targeted sample preparation.
Bioinformatics company can perform peptide sequence analysis on samples in both liquid and solid states. For solid samples, transport with ice packs; for solution samples, they can be vacuum dried or freeze-dried, and transported with ice packs or using dry ice. Feel free to contact us for consultation.
