Browse
Submit Data
Databases
API
Help

Dataset Information

16 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Effective discrimination of gas-phase peptide conformers using TIMS-ECD-ToF MS/MS.

ABSTRACT: In the present work, four, well-studied, model peptides (e.g., substance P, bradykinin, angiotensin I and AT-Hook 3) were used to correlate structural information provided by ion mobility and ECD/CID fragmentation in a TIMS-q-EMS-ToF MS/MS platform, incorporporating an electromagnetostatic cell (EMS). The structural heterogeneity of the model peptides was observed by (i) multi-component ion mobility profiles (high ion mobility resolving power, R ∼115-145), and (ii) fast online characteristic ECD fragmentation patterns per ion mobility band (∼0.2 min). Particularly, it was demonstrated that all investigated species were probably conformers, involving cis/trans-isomerizations at X-Pro peptide bond, following the same protonation schemes, in good agreement with previous ion mobility and single point mutation experiments. The comparison between ion mobility selected ECD spectra and traditional FT-ICR ECD MS/MS spectra showed comparable ECD fragmentation efficiencies but differences in the ratio of radical (˙)/prime (') fragment species (H˙ transfer), which were associated with the differences in detection time after the electron capture event. The analysis of model peptides using online TIMS-q-EMSToF MS/MS provided complementary structural information on the intramolecular interactions that stabilize the different gas-phase conformations to those obtained by ion mobility or ECD alone.

SUBMITTER: Jeanne Dit Fouque K

PROVIDER: S-EPMC8596503 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Towards Discovery and Targeted Peptide Biomarker Detection Using nanoESI-TIMS-TOF MS.

Project description:In the present work, the potential of trapped ion mobility spectrometry coupled to TOF mass spectrometry (TIMS-TOF MS) for discovery and targeted monitoring of peptide biomarkers from human-in-mouse xenograft tumor tissue was evaluated. In particular, a TIMS-MS workflow was developed for the detection and quantification of peptide biomarkers using internal heavy analogs, taking advantage of the high mobility resolution (R = 150-250) prior to mass analysis. Five peptide biomarkers were separated, identified, and quantified using offline nanoESI-TIMS-CID-TOF MS; the results were in good agreement with measurements using a traditional LC-ESI-MS/MS proteomics workflow. The TIMS-TOF MS analysis permitted peptide biomarker detection based on accurate mobility, mass measurements, and high sequence coverage for concentrations in the 10-200 nM range, while simultaneously achieving discovery measurements of not initially targeted peptides as markers from the same proteins and, eventually, other proteins. Graphical Abstract ?.

| S-EPMC5844780 | biostudies-literature

Trapped Ion Mobility Spectrometry, Ultraviolet Photodissociation, and Time-of-Flight Mass Spectrometry for Gas-Phase Peptide Isobars/Isomers/Conformers Discrimination.

Project description:Trapped ion mobility spectrometry (TIMS) when coupled with mass spectrometry (MS) offers great advantages for the separation of isobaric, isomeric, and/or conformeric species. In the present work, we report the advantages of coupling TIMS with a low-cost, ultraviolet photodissociation (UVPD) linear ion trap operated at few mbars prior to time-of-flight (ToF) MS analysis for the effective characterization of isobaric, isomeric, and/or conformeric species based on mobility-selected fragmentation patterns. These three traditional challenges to MS-based separations are illustrated for the case of biologically relevant model systems: H3.1 histone tail PTM isobars (K4Me3/K18Ac), lanthipeptide regioisomers (overlapping/nonoverlapping ring patterns), and a model peptide conformer (angiotensin I). The sequential nature of the TIMS operation allows for effective synchronization with the ToF MS scans, in addition to parallel operation between the TIMS and the UVPD trap. Inspection of the mobility-selected UVPD MS spectra showed that for all three cases considered, unique fragmentation patterns (fingerprints) were observed per mobility band. Different from other IMS-UVPD implementations, the higher resolution of the TIMS device allowed for high mobility resolving power (R > 100) and effective mobility separation. The mobility selected UVPD MS provided high sequence coverage (>85%) with a fragmentation efficiency up to ∼40%.

| S-EPMC9262853 | biostudies-literature

Probing the gas-phase folding kinetics of peptide ions by IR activated DR-ECD.

Project description:The effect of infrared (IR) irradiation on the electron capture dissociation (ECD) fragmentation pattern of peptide ions was investigated. IR heating increases the internal energy of the precursor ion, which often amplifies secondary fragmentation, resulting in the formation of w-type ions as well as other secondary fragments. Improved sequence coverage was observed with IR irradiation before ECD, likely due to the increased conformational heterogeneity upon IR heating, rather than faster breakdown of the initially formed product ion complex, as IR heating after ECD did not have similar effect. Although the ECD fragment ion yield of peptide ions does not typically increase with IR heating, in double resonance (DR) ECD experiments, fragment ion yield may be reduced by fast resonant ejection of the charge reduced molecular species, and becomes dependent on the folding state of the precursor ion. In this work, the fragment ion yield was monitored as a function of the delay between IR irradiation and the DR-ECD event to study the gas-phase folding kinetics of the peptide ions. Furthermore, the degree of intracomplex hydrogen transfer of the ECD fragment ion pair was used to probe the folding state of the precursor ion. Both methods gave similar refolding time constants of approximately 1.5 s(-1), revealing that gaseous peptide ions often refold in less than a second, much faster than their protein counterparts. It was also found from the IR-DR-ECD study that the intramolecular H. transfer rate can be an order of magnitude higher than that of the separation of the long-lived c/z product ion complexes, explaining the common observation of c. and z type ions in ECD experiments.

| S-EPMC3117249 | biostudies-literature

Rapid Discrimination of Methicillin-Resistant Staphylococcus aureus by MALDI-TOF MS.

Project description:Methicillin-resistant Staphylococcus aureus (MRSA) is a serious pathogen in clinical settings and early detection is critical. Here, we investigated the MRSA discrimination potential of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) using 320 clinical S. aureus isolates obtained in 2005-2014 and 181 isolates obtained in 2018. We conducted polymerase chain reactions (PCR) for staphylococcal cassette chromosome mec (SCCmec) typing and MALDI-TOF MS to find specific markers for methicillin resistance. We identified 21 peaks with significant differences between MRSA and methicillin-susceptible S. aureus (MSSA), as determined by mecA and SCCmec types. Each specific peak was sufficient to discriminate MRSA. We developed two methods for simple discrimination according to these peaks. First, a decision tree for MRSA based on six MRSA-specific peaks, three MSSA-specific peaks, and two SCCmec type IV peaks showed a sensitivity of 96.5%. Second, simple discrimination based on four MRSA-specific peaks and one MSSA peak had a maximum sensitivity of 88.3%. The decision tree applied to 181 S. aureus isolates from 2018 had a sensitivity of 87.6%. In conclusion, we used specific peaks to develop sensitive MRSA identification methods. This rapid and easy MALDI-TOF MS approach can improve patient management.

| S-EPMC6963962 | biostudies-literature

Discrimination between Eggs from Stink Bugs Species in Europe Using MALDI-TOF MS.

Project description:In the current paper, we used a method based on stink bug egg-protein immobilization on filter paper by drying, followed by post-(storage and shipping) extraction in acidified acetonitrile containing matrix, to discriminate between nine different species using MALDI-TOF MS. We obtained 87 correct species-identifications in 87 blind tests using this method. With further processing of the unblinded data, the highest average Bruker score for each tested species was that of the cognate reference species, and the observed differences in average Bruker scores were generally large and the errors small except for Capocoris fuscispinus, Dolycoris baccarum, and Graphosoma italicum, where the average scores were lower and the errors higher relative to the remaining comparisons. While we observed clear discrimination between the nine species using this method, Halyomorpha halys and Piezodorus lituratus were more spectrally related than the other pairwise comparisons.

| S-EPMC8303754 | biostudies-literature

Comparison of Peptide Ion Conformers Arising from Non-Helical and Helical Peptides Using Ion Mobility Spectrometry and Gas-Phase Hydrogen/Deuterium Exchange.

Project description:The dominant gas-phase conformer of [M+3H]3+ ions of the model peptide acetyl-PSSSSKSSSSKSSSSKSSSSK has been examined with ion mobility spectrometry (IMS), gas-phase hydrogen deuterium exchange (HDX), and mass spectrometry (MS) techniques. The [M+3H]3+ peptide ions are observed predominantly as a relatively compact conformer type. Upon subjecting these ions to electron transfer dissociation (ETD), the level of protection for each amino acid residue in the peptide sequence is assessed. The overall per-residue deuterium uptake is observed to be relatively more efficient for the neutral residues than for the model peptide acetyl-PAAAAKAAAAKAAAAKAAAAK. In comparison, the N-terminal and C-terminal regions of the serine peptide show greater relative protection compared with interior residues. Molecular dynamics (MD) simulations have been used to generate candidate structures for collision cross section and HDX reactivity matching. Hydrogen accessibility scoring (HAS) for select structural candidates from MD simulations has been used to suggest conformer types that could contribute to the observed HDX patterns. The results are discussed with respect to recent studies employing extensive MD simulations of gas-phase structure establishment of a peptide system. Graphical Abstract ᅟ.

| S-EPMC6553874 | biostudies-literature

MALDI-TOF MS Affords Discrimination of Deinococcus aquaticus Isolates Obtained From Diverse Biofilm Habitats.

Project description:Matrix-assisted Laser Desorption Ionization-Time of Flight Mass Spectroscopy (MALDI-TOF MS) has been used routinely over the past decade in clinical microbiology laboratories to rapidly characterize diverse microorganisms of medical importance both at the genus and species levels. Currently, there is keen interest in applying MALDI-TOF MS at taxonomic levels beyond species and to characterize environmental isolates. We constructed a model system consisting of 19 isolates of Deinococcus aquaticus obtained from biofilm communities indigenous to diverse substrates (concrete, leaf tissue, metal, and wood) in the Fox River - Lake Winnebago system of Wisconsin to: (1) develop rapid sample preparation methods that produce high quality, reproducible MALDI-TOF spectra and (2) compare the performance of MALDI-TOF MS-based profiling to common DNA-based approaches including 16S rRNA sequencing and genomic diversity by BOX-A1R fingerprinting. Our results suggest that MALDI-TOF MS can be used to rapidly and reproducibly characterize environmental isolates of D. aquaticus at the subpopulation level. MALDI-TOF MS provided higher taxonomic resolution than either 16S rRNA gene sequence analysis or BOX-A1R fingerprinting. Spectra contained features that appeared to permit characterization of isolates into two co-occurring subpopulations. However, reliable strain-level performance required rigorous and systematic standardization of culture conditions and sample preparation. Our work suggests that MALDI-TOF MS offers promise as a rapid, reproducible, and high-resolution approach to characterize environmental isolates of members of the genus Deinococcus. Future work will focus upon application of methods described here to additional members of this ecologically diverse and ubiquitous genus.

| S-EPMC6196315 | biostudies-literature

Chemical Discrimination of Astragalus mongholicus and Astragalus membranaceus Based on Metabolomics Using UHPLC-ESI-Q-TOF-MS/MS Approach.

Project description:Astragalus mongholicus (MG) and Astragalus membranaceus (MJ), both generally known as Huangqi in China, are two perennial herbals widely used in variety diseases. However, there were still some differences in the chemical ingredients between MG and MJ. In this paper, metabolomics combined with the ultra-high performance liquid chromatography coupled with electrospray ionization/quadrupole time-of-flight mass spectrometry (UHPLC-ESI-Q-TOF-MS/MS) was employed to contrastively analyze the chemical constituents between MG and MJ. As a result, principal component analysis showed that MG and MJ were separated clearly. A total of 53 chemical markers were successfully identified for the discrimination of MG and MJ. Of them, the contents of 36 components including Astragaloside I~III, Astragaloside IV, Agroastragaloside I, etc. in MJ were significantly higher than those in MG. On the contrary, the contents of 17 other components including coumaric acid, formononetin, sophoricoside, etc. in MG were obviously higher than those in MJ. The results showed that the distinctive constituents in MG and MJ were remarkable, and MJ may own stronger pharmacological activities than MG. In a word, MG and MJ may be treated as two different herbs. This paper demonstrated that metabolomics was a vitally credible technology to rapidly screen the characteristic chemical composition of traditional Chinese medicine.

| S-EPMC6891664 | biostudies-literature

Phenylisoserine in the gas-phase and water: Ab initio studies on neutral and zwitterion conformers.

Project description:The conformational landscape of phenylisoserine (PhIS) was studied. Trial structures were generated by allowing for all combinations of single-bond rotamers. Based on the B3LYP/aug-cc-pVDZ calculations 54 conformers were found to be stable in the gas phase. The six most stable conformers were further optimized at the B3LYP/aug-cc-pVTZ and MP2/aug-cc-pVDZ levels for which characteristic intramolecular hydrogen bond types were classified. To estimate the influence of water on PhIS conformation, the IEF-PCM/B3LYP/aug-cc-pVDZ calculations were carried out and showed 51 neutral and six zwitterionic conformers to be stable in water solution. According to DFT calculations, the conformer equilibrium in the gas phase is dominated by one conformer, whereas the MP2 calculations suggest three PhIS structures to be significantly populated. Comparison of DFT and MP2 energies of all 57 structures stable in water indicates that, in practice, one zwitterionic and one neutral conformer determine the equilibrium in water. Based on the AIM calculations, we found that for the neutral conformers in vacuum and in water, d(H...B) is linearly correlated with Laplacian at the H-bond critical point. Figure Phenylisoserine (PhIS) is an active side chain of cytotoxic Paclitaxel medicine. The conformational landscape of phenylisoserine was studied. One zwitterionic and one neutralconformer determine the equilibrium in water whereas in the gas phase the MP2 calculations suggest three PhIS structures to be significantly populated.

| S-EPMC3094660 | biostudies-literature

Photocleavable peptide-oligonucleotide conjugates for protein kinase assays by MALDI-TOF MS.

Project description:Robust methods for highly parallel, quantitative analysis of cellular protein tyrosine kinase activities may provide tools critically needed to decipher oncogenic signaling, discover new targeted drugs, diagnose cancer and monitor patients. Here, we describe proof-of-principle for a novel protein kinase assay with the potential to help overcome these challenges. MALDI-TOF mass spectrometry provides an ideal tool for label-free multiplexed analysis of peptide phosphorylation, but is poorly matched to homogeneous assays and complex samples. Thus, we conjugated a common oligonucleotide tag to multiple peptide substrates, offering efficient capture from solution-phase kinase reactions by annealing to the complementary sequence tethered to PEG-passivated superparamagnetic microparticles. To enable reversible conjugation, we developed a novel bifunctional cross-linker allowing simple and efficient preparation of photocleavable peptide-oligonucleotide conjugates. After washing away contaminants and following photorelease, MALDI-TOF analysis yielded relative phosphorylation of each peptide with high sensitivity and specificity. Validating the hybridization-mediated multiplexed kinase assay, when three peptide substrate-oligonucleotide conjugates were mixed with the tyrosine kinase c-Abl and ATP, we readily observed their differential phosphorylation yet measured a common IC(50) for the Abl kinase inhibitor imatinib. This new assay enables analysis of protein kinase activities in a multiplexed format amenable to screening inhibitors against multiple kinases in parallel, an important capability for drug discovery and predictive diagnostics.

| S-EPMC3462237 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data