CMSP offers a wide range of discovery-based proteomics services from a large variety of sample types. For these experiments, no knowledge of the protein composition of the sample is required. Proteins are subjected to proteolytic digestion prior to mass spectrometry analysis for a ‘bottom-up’ approach for protein detection.
In-Gel and In-Solution Protein Identifications. We accept 1D SDS-PAGE gel bands, 2D gel spots, GeLC samples (contiguous regions of a 1D gel lane, typically from a complex proteome) and proteins in solution for the purpose of protein identification. We perform proteolytic digestion with trypsin or other proteolytic enzymes prior to mass spectrometry analysis. We offer services to train researchers on the proteolysis techniques and we also accept samples from customers who have completed the proteolysis in their own lab.
Pull-downs and Co-IP (Co-immunoprecipitation). Proteins that form stable complexes during a pull-down or co-IP performed in the lab of the investigator can be detected after proteolytic digestion and mass spectrometry analysis. Typically, eluted proteins are separated by SDS-PAGE and processed by in-gel proteolysis. In select cases, proteolysis can be performed directly on the solid support.
Interactome analysis. Proximity-labeling techniques (including BioID, TurboID, APEX) can be used for interaction-based proteomics investigations. Protein complexes with unstable or transient interactions can be studied using these technologies with higher success than traditional pull-downs or co-IP. After enrichment of tagged proteins in the lab of the investigator, protein samples can be submitted to CMSP for proteolytic digestion and mass spectrometry analysis.
Protein Characterization and Validation. Detection of targeted amino acid modifications and mutations can be interrogated by mass spectrometry analysis of proteolytic fragments. Peptide tandem mass spectrometry results can be used for validation, typically in conjunction with mass spectrometry of authentic standards or with proper control experiments. CMSP provides assistance to maximize protein sequence coverage or target protein sequence regions of interest with multiple proteolytic enzymes and custom digestion conditions and will assist with inspection of peptide tandem mass spectra in support of expected amino acid mutations or modifications.