Integrated Top-down/Bottom-up Proteomics for the Characterization of Protein Isoforms

Presented by: Ljiljana Paša-Tolić, Ph.D., Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory

Description: Obtaining extended sequence coverage of intact proteins and characterizing multiple post-translational modification (PTM) sites can pose key technical challenges. In this webinar, we describe how we have implemented Advion’s TriVersa NanoMate® and RePlay® technologies to address these issues using an integrated top-down/bottom-up approach.

We demonstrate how the TriVersa NanoMate’s capabilities of chip-based electrospray ionization (ESI) and fraction collection are used to profile isoforms, further investigate targeted proteins at the intact level using ECD or CID, perform bottom-up proteomics on a collected fraction to get confident protein identifications, perform targeted MS/MS on particular fractions of interest, and better characterize where PTMs may have occurred.

We also discuss how RePlay simplifies the data analysis process by allowing you to see the correlation between the intact protein and the observed peptides, even when you are sample limited. Using RePlay, we incorporated an on-line digestion strategy with the integrated top-down/bottom-up approach. This technique allows you to implement LC-MS/MS during both the intact run and a secondary RePlay run with digestion, so you can see the correlation in time between the observed parent ions and the digested ions as well as the MS/MS of the fragment ions.