Dataset Information

Comprehensive identification of crosslinked peptides from methyltransferase Hmt1 and its substrate Npl3: use of multiple crosslinkers, mass spectrometry approaches and software platforms

ABSTRACT: Chemical-Crosslinking Mass Spectrometry (XLMS) using MS-cleavable crosslinkers is fast becoming an established technique in the study of protein-protein interactions for both small and large scale samples. With the increased uptake of XLMS as a technique, different combinations of crosslinker types, fragmentation strategies and analysis programs are being applied to a diverse array of biological samples. This study is focused on understanding how the three variables of an XLMS experiment – crosslinker type, fragmentation and program – could generate differences in identifications, leading to increased biological coverage of a sample. Here we probe for the first time, the known enzyme:substrate interaction between yeast arginine methyltransferase Hmt1p and its substrate, heterologous nucleolar protein Npl3p. We use this known interaction as a platform to compare two analysis programs, MeroX and XlinkX2.0, using two crosslinker types, DSSO and DSBU, and two mass-spectrometry fragmentation strategies, CID/ETD and SteppedHCD. Through these we also compare different algorithm strategies, Precursor and Reporter-Ion, as well as assess the impact of restricting data searches to lysine only crosslinks versus the inclusion of serine, threonine and tyrosine as reactive residues. From this analysis we show direct evidence of Hmt1p in contact with its known methylation sites on Npl3p, the intrinsically disordered “SRGG” region. We also show through our multi-crosslinker, multi-fragmentation and multi-software approach that two approaches leads to greater understanding and depth of a crosslinked sample, and this is due to some combinations of experimental variables creating greater coverage of crosslinks than others.

INSTRUMENT(S): Orbitrap Fusion Lumos, Q Exactive Plus

ORGANISM(S): Escherichia Coli Saccharomyces Cerevisiae (baker's Yeast)

SUBMITTER: Daniela-Lee Smith

LAB HEAD: Marc R Wilkins

PROVIDER: PXD008348 | Pride | 2018-07-20

REPOSITORIES: Pride

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Publications

Characterization of the Interaction between Arginine Methyltransferase Hmt1 and Its Substrate Npl3: Use of Multiple Cross-Linkers, Mass Spectrometric Approaches, and Software Platforms.

Smith Daniela-Lee DL Götze Michael M Bartolec Tara K TK Hart-Smith Gene G Wilkins Marc R MR

Analytical chemistry 20180725 15

This study investigated the enzyme-substrate interaction between Saccharomyces cerevisiae arginine methyltransferase Hmt1p and nucleolar protein Npl3p, using chemical cross linking/mass spectrometry (XL/MS). We show that XL/MS can capture transient interprotein interactions that occur during the process of methylation, involving a disordered region in Npl3p with tandem SRGG repeats, and we confirm that Hmt1p and Npl3p exist as homomultimers. Additionally, the study investigated the interdependen ...[more]

PMID: 30004689

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Project description:Crosslinking mass spectrometry (XL-MS) is emerging as a unique method at the crossroads of structural and cellular biology, uniquely capable of identifying protein-protein interactions with residue-level resolution and on the proteome-wide scale. With the development of crosslinkers that can form linkages inside cells and easily cleave during fragmentation on the mass spectrometer (MS-cleavable crosslinks), it has become increasingly facile to identify contacts between any two proteins in complex samples, including in live cells or tissues. Photo-crosslinkers possess the advantages of high temporal resolution and high reactivity, thereby engaging all residue-types (rather than just lysine); nevertheless, photo-crosslinkers have not enjoyed widespread use, and have yet to be employed for proteome-wide studies, because their products are challenging to identify, and an MS-cleavable photo-crosslinker has not yet been reported. Here, we demonstrate the synthesis and application of two heterobifunctional photo-crosslinkers that feature diazirines and N-hydroxy-succinimidyl carbamate groups, the latter of which unveil MS-cleavable linkage upon acyl transfer to protein targets. Moreover, these crosslinkers demonstrate high water-solubility and cell-permeability. Using these compounds, we demonstrate the feasibility of proteome-wide photo-crosslinking mass spectrometry (photo-XL-MS), both in extracts and in cellulo. These studies provide a partial interaction map of the E. coli cytosol with residue-level resolution. We find that photo-XL-MS has a propensity to capture protein-protein interactions, particularly involving low-abundance uncharacterized proteins, suggesting it could be a powerful tool to shed light on the “darker” corners of the proteome. Overall, we describe methods that enable the detection of protein quinary interaction networks in their native environment at residue-level resolution proteome-wide, and we expect they will prove useful toward the effort to explore the molecular sociology of the cell.

Dataset Information

Comprehensive identification of crosslinked peptides from methyltransferase Hmt1 and its substrate Npl3: use of multiple crosslinkers, mass spectrometry approaches and software platforms

Publications

Characterization of the Interaction between Arginine Methyltransferase Hmt1 and Its Substrate Npl3: Use of Multiple Cross-Linkers, Mass Spectrometric Approaches, and Software Platforms.

Similar Datasets

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