Dataset Information

Spatial Proteomics by Trapped Ion Mobility supported MALDI MS/MS Imaging: A First Glance into Multiplexed and Spatial Peptide Identification

ABSTRACT: RATIONALE In spatial proteomics, matrix-assisted laser desorption/ionization (MALDI) imaging enables rapid and cost-effective peptide measurement. Yet, in situ peptide identification remains challenging. Therefore, this study aims to integrate the trapped ion mobility spectrometry (TIMS)-based parallel accumulation-serial fragmentation (PASEF) into MALDI imaging of peptides to enable multiplexed MS/MS imaging. METHODS An initial MALDI TIMS MS1 survey measurement is performed, followed by a manual generation of a precursor list containing mass over charge values and ion mobility windows. Inside the dual TIMS system, submitted precursors are trapped, separately eluted by their ion mobility and analyzed in a quadrupole time-of-flight device, thereby enabling multiplexed MALDI MS/MS imaging. Finally, precursors are identified by peptide to spectrum matching. RESULTS This study presents the first multiplexed MALDI TIMS MS/MS imaging (iprm-PASEF) of tryptic peptides. Its applicability is showcased on two histomorphologically distinct tissue specimens in a 4-plex and 5-plex setup. Precursors were successfully identified by the search engine MASCOT in one single MALDI imaging experiment for each respective tissue. Peptide identifications were corroborated by liquid-chromatography tandem mass spectrometry experiments and fragment colocalization analyses. CONCLUSIONS In the present study, we demonstrate the feasibility of TIMS-based MALDI MS/MS imaging for the multiplexed and rapid identification of tryptic peptides in a spatial manner. Hence, it represents a first step towards the integration of MALDI imaging into the emerging field of spatial proteomics. The datasets will be uploaded separately. This data set contains the PDX MS1 data. There are two tissues vissible on the.tif image. The relevant one is on the left side of the slide (away from the barcode).

INSTRUMENT(S): timsTOF fleX

ORGANISM(S): Human

SUBMITTER: Prof. Oliver Schilling