Proteomics—the recognition and analysis of proteins in cells or tissues, including protein expression level, cell location, protein interaction, post translation modification, etc., is developed under the impetus of modern science and technology, such as peptide/protein separation, mass spectrometry, quantitative isotope labeling and bioinformatics analysis, whose development is closely related to mass spectrometry that has recently become a core tool in the field of proteomics and biomacromolecule research. As the progress of protein identification, quantification and analysis, scientists not only have higher and higher requirements for the resolution, sensitivity, quality accuracy and scanning rate of mass spectrometer, but also other relevant skills. Creative Biolabs, as a professional problem solver in the regarding area, has launched the Database Assisted Shotgun Sequencing (DASS)—a novel technique focused on antibody/protein de novo sequencing, which has unprecedentedly achieve absolute differentiation of leucine and isoleucine.

• Sequencing of the V and J and C Segments

It is workable to resolve sequences of proline and arginine-rich peptides, making clear the order of the amino acids. In spite of the hypermutations introduced by B cells during maturation process, the mapping algorithm can automatically match the peptides that have been mutated to the corresponding germline precisely, thus relieving from other time-costing procedures like Edam sequencing.

• De Novo Sequencing of the CDR3 Region

During the fragmentation process, the applied techniques generate rich overlapping peptides, making unknown, long amino acids applicable to sequencing process, which with MS/MS spectra and intelligent data mining, resulting in the CDR3 unfolded like a readable book. Even a 20 kDa protein with no homolog in the database can be sequenced.

• Sequencing of Fluorochrome mAbs, IgMs, and other Non-Standard Antibodies

The above mentioned antibody types can find corresponding sequencing solutions, helped with the DASS. Precious, dilute samples with hosts like mouse, rat, hamster, llama in formats like Fab, scFv, etc., new or old can find sequencing solutions, which will ensure convincing outcomes.

• Isobaric Amino Acids

Most isobaric amino acid compositions can be discriminated with the help of DASS, including but are unlimited to, Leucine & Isoleucine, W & GE, AD & SV, R & GV, N & GG (GG bond breakage ensured), Q & GA (GA bond breakage ensured).

All of the sequencing solutions are guaranteed for validation, with the light/heavy chain validated, of which the light chain match within +/- 1.2, and heavy chain +/- 1.8 Da. In addition, mutation in the antibody will undergo validation through at least two meaningful spectra to ensure isobaric exchange free.

On the antibody level, the launch of DASS technique in the field of antibody/protein sequencing is a blockbuster that can 100% differentiate between leucine and isoleucine in a fast turnaround period, surpassing the conventional way of sequencing on aspects of speed, sensitivity, accuracy and compatibility. On the protein level, complete amino acid sequence information and post-translational modification information can be obtained to support further protein identification. The long-term goal of the scientific staff working on the database assisted shotgun sequencing is to improve global medical researcher and medicine manufactures’ projects by means of technical support and one-stop solutions.