Application of LTQ-Orbitrap Top Down Analysis of Small Plasma Proteins: a Model Study with Transthyretin

摘要

Whilst the use of top down techniques have been explored on a variety of instrument configurations, the LTQ-Orbitrap presents an efficient alternative offering (1) ease of use (2) very high resolution and (3) various forms of multistage (MS~(n)) capability. This high performance mass spectrometer coupled with the Advion TriVersa (sample delivery system), the use of Xtract software (deconvolution) and ProSight (fragment assignment) allowed quick mapping of protein fragmentation. In-house software tools were developed to more fully mine top down data by identifying internal fragment ions. We have explored the capabilities of this analytical platform using the plasma protein transthyretin (TTR). The goal of this investigation is to examine parameters affecting spectrum acquisition for high-throughput top down analysis of small proteins isolated from plasma for sequence elucidation and post-translational modification (PTM) characterization.