Journal of the American Society for Mass Spectrometry最新文献

Machine Learning Correlation of Electron Micrographs and ToF-SIMS for the Analysis of Organic Biomarkers in Mudstone.

IF 3.1 2区化学

Journal of the American Society for Mass Spectrometry Pub Date : 2024-12-19 DOI: 10.1021/jasms.4c00300

Michael J Pasterski, Matthias Lorenz, Anton V Ievlev, Raveendra C Wickramasinghe, Luke Hanley, Fabien Kenig

{"title":"Machine Learning Correlation of Electron Micrographs and ToF-SIMS for the Analysis of Organic Biomarkers in Mudstone.","authors":"Michael J Pasterski, Matthias Lorenz, Anton V Ievlev, Raveendra C Wickramasinghe, Luke Hanley, Fabien Kenig","doi":"10.1021/jasms.4c00300","DOIUrl":"https://doi.org/10.1021/jasms.4c00300","url":null,"abstract":"The spatial distribution of organics in geological samples can be used to determine when and how these organics were incorporated into the host rock. Mass spectrometry (MS) imaging can rapidly collect a large amount of data, but ions produced are mixed without discrimination, resulting in complex mass spectra that can be difficult to interpret. Here, we apply unsupervised and supervised machine learning (ML) to help interpret spectra from time-of-flight-secondary ion mass spectrometry (ToF-SIMS) of an organic-carbon-rich mudstone of the Middle Jurassic of England (UK). It was previously shown that the presence of sterane molecular biomarkers in this sample can be detected via ToF-SIMS (Pasterski, M. J. et al., Astrobiology 2023, 23, 936). We use unsupervised ML on scanning electron microscopy-electron dispersive spectroscopy (SEM-EDS) measurements to define compositional categories based on differences in elemental abundances. We then test the ability of four ML algorithms─k-nearest neighbors (KNN), recursive partitioning and regressive trees (RPART), eXtreme gradient boost (XGBoost), and random forest (RF)─to classify the ToF-SIM spectra using (1) the categories assigned via SEM-EDS, (2) organic and inorganic labels assigned via SEM-EDS, and (3) the presence or absence of detectable steranes in ToF-SIMS spectra. In terms of predictive accuracy and balanced accuracy, KNN was the best performing model and RPART the worst. The feature importance, or the specific features of the ToF-SIM spectra used by the models to make classifications, cannot be determined for KNN, preventing posthoc model interpretation. Nevertheless, the feature importance extracted from the other models was useful for interpreting spectra. We determined that some of the organic ions used to classify biomarker containing spectra may be fragment ions derived from kerogen which is abundant in this mudstone sample.","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142851700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Predicting Precursor Ions Combined with Fragmentation Pathway for Screening and Identification of Flavan-3-ol Oligomers in Tea (Camellia sinensis. var. assamica).

IF 3.1 2区化学

Journal of the American Society for Mass Spectrometry Pub Date : 2024-12-18 DOI: 10.1021/jasms.4c00390

Min Feng, Yonglin Li, Yanfang Qin, Wensi Ma, Dabing Ren, Lunzhao Yi

{"title":"Predicting Precursor Ions Combined with Fragmentation Pathway for Screening and Identification of Flavan-3-ol Oligomers in Tea (Camellia sinensis. var. assamica).","authors":"Min Feng, Yonglin Li, Yanfang Qin, Wensi Ma, Dabing Ren, Lunzhao Yi","doi":"10.1021/jasms.4c00390","DOIUrl":"https://doi.org/10.1021/jasms.4c00390","url":null,"abstract":"Flavan-3-ol oligomers (FLOs), including proanthocyanidins (PAs) and theasinensins (TSs), contribute greatly to the flavor and bioactivity of the tea beverage. Ultrahigh-performance liquid chromatography coupled with high-resolution mass spectrometry has been widely used in profiling a wide range of compounds in tea. However, the detection and identification of FLOs with low concentration and high structural diversity remain meaningful yet challenging work. Herein, we propose a strategy that enables efficient discovery and annotation of FLOs, especially those with a relatively high degree of polymerization (DP, ≥3). Based on the known monomers and the specific polymerization pattern between them, the strategy predicted a theoretical list of precursor ions of FLO. Matching the predicted list against the experimental ion features screened out 490 features as the candidate of FLOs from over 10 000 raw features. Investigation of the fragmentation pathways of 17 known FLOs found that both PAs and TSs are easily subjected to RDA cleavage, which produced a series of characteristic fragmentation ions and neutral losses. Moreover, successive cleavage of the C4 → C8 bond between monomer units is observed for PAs, leading to the generation of characteristic fragmentation ions corresponding to monomeric flavan-3-ols. Assisted by the characteristic fragmentation pathways, 52 FLOs (DP: 2-6) were finally annotated from the 490 retained features. Their chemical structures were verified by depolymerization experiments using menthofuran as the nucleophilic trapping reagent. Among them, the pentamers and hexamers were detected in a Yunnan large leaf tea for the first time. Semiquantitation and multivariate statistical analysis indicate that PAs exhibit higher contents in green tea, and TSs show higher levels in black and white tea.","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142851722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Interpolation of Imaging Mass Spectrometry Data by a Window-Based Adversarial Autoencoder Method.

IF 3.1 2区化学

Journal of the American Society for Mass Spectrometry Pub Date : 2024-12-17 DOI: 10.1021/jasms.4c00372

Lili Xu, Qing Zhai, Ariful Islam, Takumi Sakamoto, Chi Zhang, Shuhei Aramaki, Tomohito Sato, Ikuko Yao, Tomoaki Kahyo, Mitsutoshi Setou

{"title":"Interpolation of Imaging Mass Spectrometry Data by a Window-Based Adversarial Autoencoder Method.","authors":"Lili Xu, Qing Zhai, Ariful Islam, Takumi Sakamoto, Chi Zhang, Shuhei Aramaki, Tomohito Sato, Ikuko Yao, Tomoaki Kahyo, Mitsutoshi Setou","doi":"10.1021/jasms.4c00372","DOIUrl":"https://doi.org/10.1021/jasms.4c00372","url":null,"abstract":"Imaging mass spectrometry (IMS) is a technique for simultaneously acquiring the expression and distribution of molecules on the surface of a sample, and it plays a crucial role in spatial omics research. In IMS, the time cost and instrument load required for large data sets must be considered, as IMS typically involves tens of thousands of pixels or more. In this study, we developed a high-resolution method for IMS data reconstruction using a window-based Adversarial Autoencoder (AAE) method. We acquired IMS data from partial cerebellum regions of mice with a pitch size of 75 μm and then down-sampled the data to a pitch size of 150 μm, selecting 22 m/z peak intensity values per pixel. We established an AAE model to generate three pixels from the surrounding nine pixels within a window to reconstruct the image data at a pitch size of 75 μm. Compared with two alternative interpolation methods, Bilinear and Bicubic interpolation, our window-based AAE model demonstrated superior performance on image evaluation metrics for the validation data sets. A similar model was constructed for larger mouse kidney tissues, where the AAE model achieved high image evaluation metrics. Our method is expected to be valuable for IMS measurements of large animal organs across extensive areas.","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142833383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

MS SIEVE-Pushing the Limits for Biomolecular Mass Spectrometry.

IF 3.1 2区化学

Journal of the American Society for Mass Spectrometry Pub Date : 2024-12-17 DOI: 10.1021/jasms.4c00343

Kudratullah Karimi, Jonathan Zöller, Tommy Hofmann, Rene Zangl, Jonathan Schulte, Julian D Langer, Carla Schmidt, Nina Morgner

{"title":"MS SIEVE-Pushing the Limits for Biomolecular Mass Spectrometry.","authors":"Kudratullah Karimi, Jonathan Zöller, Tommy Hofmann, Rene Zangl, Jonathan Schulte, Julian D Langer, Carla Schmidt, Nina Morgner","doi":"10.1021/jasms.4c00343","DOIUrl":"https://doi.org/10.1021/jasms.4c00343","url":null,"abstract":"Electrospray mass spectrometry has become indispensable in many disciplines including the classic \"omics\" techniques such as proteomics or lipidomics, as well as other life science applications in molecular, cellular, and structural biology. However, a limiting factor that often arises for the detection of biomolecular analytes is their poor ionization efficiency in the ion source. Here, we present an add-on device for the electrospray source, termed MS SIEVE (MS Spectral Impurity Eliminator & Value Enhancer), which is placed between the electrospray needle and the cone of the mass spectrometer. We probed the application of MS SIEVE for various biomolecules including proteins, peptides, lipids, glycans and DNA oligonucleotides and even synthetic polymers such as polyethylene glycol and found that MS SIEVE selectively improves the signal intensity, while suppressing the spectral contribution of contaminants such as NaCl. Importantly, MS SIEVE can, in principle, be adapted for any electrospray ion source and, therefore, represents a promising alternative for routine \"omics\" methods as well as special applications on challenging analytes.","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142845480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Photochemical and Collision-Induced Cross-Linking of Lys, Arg, and His to Nitrile Imines in Peptide Conjugate Ions in the Gas Phase.

IF 3.1 2区化学

Journal of the American Society for Mass Spectrometry Pub Date : 2024-12-17 DOI: 10.1021/jasms.4c00438

Jiahao Wan, Mikuláš Vlk, Marianna Nytka, Tuan Ngoc Kim Vu, Karel Lemr, František Tureček

{"title":"Photochemical and Collision-Induced Cross-Linking of Lys, Arg, and His to Nitrile Imines in Peptide Conjugate Ions in the Gas Phase.","authors":"Jiahao Wan, Mikuláš Vlk, Marianna Nytka, Tuan Ngoc Kim Vu, Karel Lemr, František Tureček","doi":"10.1021/jasms.4c00438","DOIUrl":"https://doi.org/10.1021/jasms.4c00438","url":null,"abstract":"We report a study of internal covalent cross-linking with photolytically generated diarylnitrile imines of N-terminal arginine, lysine, and histidine residues in peptide conjugates. Conjugates in which a 4-(2-phenyltetrazol-5-yl)benzoyl group was attached to C-terminal lysine, that we call RAAA-tet-K, KAAA-tet-K, and HAAA-tet-K, were ionized by electrospray and subjected to UV photodissociation (UVPD) at 213 nm. UVPD triggered loss of N2 and proceeded by covalent cross-linking to nitrile imine intermediates that involved the side chains of N-terminal arginine, lysine, and histidine, as well as the peptide amide groups. Cross-linking yields were determined from UVPD-MS2 measurements as 67%, 66%, and 84% for RAAA-tet-K, KAAA-tet-K, and HAAA-tet-K ions, respectively. CID-MS3 of the denitrogenated ion intermediates from RAAA-tet-K, KAAA-tet-K, and HAAA-tet-K indicated overall cross-linking yields of 80%, 89%, and 80%, respectively. The nature of the cross-linking reactions and cross-link structures were investigated for RAAA-tet-K by high-resolution cyclic ion mobility mass spectrometry that identified precursor ion conformers and multiple dissociation products. All sequences were subjected to conformational analysis by Born-Oppenheimer molecular dynamics, and energy analysis by density functional theory calculations with M06-2X/def2qzvpp that provided relative and dissociation energies for several cross-link structural types. The cross-linking reactions were substantially exothermic, driving the efficient conversion of nitrile-imine intermediates to cyclic products. The principal steps in covalent cross-linking involved proton transfer onto the nitrile imine group accompanied by nucleophilic attack by the peptide side-chain and amide groups. Blocking the proton transfer and nucleophile resulted in a loss of cross-linking abilities.","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142845481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Faces of Mass Spectrometry/Pavel Bondarenko.

IF 3.1 2区化学

Journal of the American Society for Mass Spectrometry Pub Date : 2024-12-16 DOI: 10.1021/jasms.4c00476

Anne Brenner, J D Brookbank

引用次数: 0

Identification and Structural Elucidation of Acylsugars in Tomato Leaves Using Liquid Chromatography-Ion Mobility-Tandem Mass Spectrometry (LC-IM-MS/MS). 利用液相色谱-离子迁移-串联质谱法（LC-IMS/MS）鉴定和阐明番茄叶中的酰化糖结构

IF 3.1 2区化学

Journal of the American Society for Mass Spectrometry Pub Date : 2024-12-16 DOI: 10.1021/jasms.4c00376

Kimberly Y Kartowikromo, Jessica S Pizzo, Thiago Rutz, Zachary E Love, Alvin M Simmons, Ann S Ojeda, Andre L B R da Silva, Camila Rodrigues, Ahmed M Hamid

{"title":"Identification and Structural Elucidation of Acylsugars in Tomato Leaves Using Liquid Chromatography-Ion Mobility-Tandem Mass Spectrometry (LC-IM-MS/MS).","authors":"Kimberly Y Kartowikromo, Jessica S Pizzo, Thiago Rutz, Zachary E Love, Alvin M Simmons, Ann S Ojeda, Andre L B R da Silva, Camila Rodrigues, Ahmed M Hamid","doi":"10.1021/jasms.4c00376","DOIUrl":"https://doi.org/10.1021/jasms.4c00376","url":null,"abstract":"Leaves of tomato plants contain various glandular trichomes that produce a wide range of metabolic products including acylsugars, which may serve as a defense mechanism against various insect pests. Acylsugars exhibit significant structural diversity, differing in their sugar cores, acylated positions, and type of acyl chains. This work demonstrated a comprehensive approach using multidimensional separation techniques, specifically liquid chromatography-ion mobility-tandem mass spectrometry (LC-IM-MS/MS), for structural characterization, and the discrimination of different tomato plants (one cultivar and five accessions) was demonstrated using tomato leaf extracts; six genotypes from five species of Solanum were represented. As a result, we identified 16 acylsugars through their molecular formulas and annotations using LC and MS analyses. The incorporation of ion mobility (IM) analysis revealed an additional 9 isomeric forms, resulting in a comprehensive total of 25 isomeric acylsugars identified. Furthermore, the experimental collision cross section (CCSexp) values agreed reasonably well with the corresponding predicted values (CCSpred), with an overall estimated error of less than 2%. These findings pave the way for research into how the different structural isomers of acylsugars might influence the self-defense mechanism in plants. Moreover, this work demonstrated that the investigated cultivar and accessions of tomatoes can be distinguished from each other based on their metabolite profile, e.g., acylsugars, with principal component analysis (PCA) and linear discriminant analysis (LDA) statistical models, yielding a prediction rate of 98.3%.","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142833368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Investigation of Real-Time Gaseous Thermal Decomposition Products of Representative Per- and Polyfluoroalkyl Substances (PFAS).

IF 3.1 2区化学

Journal of the American Society for Mass Spectrometry Pub Date : 2024-12-12 DOI: 10.1021/jasms.4c00357

Kateřina Litvanová, Bethany Klemetsrud, Feng Xiao, Alena Kubátová

{"title":"Investigation of Real-Time Gaseous Thermal Decomposition Products of Representative Per- and Polyfluoroalkyl Substances (PFAS).","authors":"Kateřina Litvanová, Bethany Klemetsrud, Feng Xiao, Alena Kubátová","doi":"10.1021/jasms.4c00357","DOIUrl":"https://doi.org/10.1021/jasms.4c00357","url":null,"abstract":"The thermal decomposition of per- and poly fluoroalkyl substances (PFAS) is poorly understood. Here, we present an innovative, comprehensive analytical method to investigate their thermal decomposition, including perfluorocarboxylic acids (PFCAs), alcohol, sulfonates, and GenX (acid dimer), focusing on identifying their breakdown products. In this study, evolved gas analysis-mass spectrometry (EGA-MS) was used for fast real-time screening to determine the significant temperatures to be investigated with the thermal desorption-pyrolysis coupled with gas chromatography-mass spectrometry (TD-Py-GC-MS), which provided detailed information about evolved PFAS and their breakdown products. This approach enabled a systematic study of perfluorocarboxylic acids (PFCAs) ranging from C3 to C9 and GenX showing volatilization, followed by degradation and formation of respective perfluorinated-1-alkenes and C5F10O perfluorinated ether (from GenX). At elevated temperatures (e.g., 600 °C), the products observed included perfluorinated butene and higher molecular-weight products, likely formed by pyrolytic polymerization of perfluorinated radicals. 1H,1H,2H,2H-perfluoro-1-decanol, i.e., 8:2 FTOH, volatilized at 100 °C; however, at higher temperatures, several novel decomposition products were observed, including perfluoro-1-decene and perfluorinated compounds suggesting the presence of the hydroxylic group. Our method offers an alternative approach to studying the thermal behavior of currently regulated and emerging PFAS with a focus on application to a wide range of matrices (laboratory grade standards or environmental samples).","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142816970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

NIST Library Identification Probabilities Are the Highest with Cold EI Mass Spectra.

IF 3.1 2区化学

Journal of the American Society for Mass Spectrometry Pub Date : 2024-12-12 DOI: 10.1021/jasms.4c00441

Aviv Amirav, Benny Neumark, Oneg Elkabets, Tal Alon

{"title":"NIST Library Identification Probabilities Are the Highest with Cold EI Mass Spectra.","authors":"Aviv Amirav, Benny Neumark, Oneg Elkabets, Tal Alon","doi":"10.1021/jasms.4c00441","DOIUrl":"https://doi.org/10.1021/jasms.4c00441","url":null,"abstract":"Cold EI improves all of the central GC-MS performance aspects, but even though it is known for providing enhanced molecular ions, it is important to realize that Cold EI mass spectra also include all of the standard EI fragment ions. Thus, Cold EI mass spectra are fully compatible with mass spectral libraries, such as NIST for sample identification. As a result, Cold EI mass spectra (unlike any other soft ionization method) provide highly effective identifications that are often better than those obtained with standard EI for a few reasons:1).Cold EI mass spectra with enhanced molecular ions typically provide higher identification probabilities than standard EI, even though scoring lower matching factors (false alternatives scores are lowered much more).2).The visually observed molecular ions further serve to confirm or reject the NIST library identifications.3).Molecular ions provide isotope abundances that serve with our TAMI software for automatic confirmation or rejection of the NIST library identification and provide an elemental formula in case the compound is not in the library.4).The Cold EI identification probability can be even higher than that of a mass spectrum with a perfect match of 999 that can be obtained by NIST library searching its own mass spectrum.5).The clear Cold EI molecular ion enables the use of the NIST library option of constraints search with the molecular ion that further significantly increases the identification probability. Our findings are demonstrated with mass spectra of hexadecane (n-C16H34), n-C40H82, pyrene, nitrobenzene, chlorpromazine, di-n-octyl phthalate, and deltamethrin.","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142811832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Comparison of Partially Denatured Cytochrome c Structural Ensembles in Solution and Gas Phases Using Cross-Linking Mass Spectrometry.

IF 3.1 2区化学

Journal of the American Society for Mass Spectrometry Pub Date : 2024-12-12 DOI: 10.1021/jasms.4c00388

Rebecca L Cain, Ian K Webb

{"title":"Comparison of Partially Denatured Cytochrome c Structural Ensembles in Solution and Gas Phases Using Cross-Linking Mass Spectrometry.","authors":"Rebecca L Cain, Ian K Webb","doi":"10.1021/jasms.4c00388","DOIUrl":"https://doi.org/10.1021/jasms.4c00388","url":null,"abstract":"Electrospray ionization mass spectrometry (ESI-MS) can retain intact protein structures, but details about partially folded and unfolded protein structures during and after introduction to the gas phase are elusive. Here we use ESI-MS with chemical cross-linkers to compare denatured cytochrome c structures in both solution and gas phases. Solution phase cross-linking prior to ESI captures solution phase structures, while gas phase cross-linking through ion/ion reactions in the trap cell captures gas phase structures. Comparing the ECD fragmentation of the cross-linked products under both conditions shows very similar cross-linker identifications, alluding to no major structural dissimilarities between solution and gas structures. Molecular modeling of the denatured protein using the identified cross-linked sites as distant restraints allows for visualization of the denatured structures to pinpoint where unfolding begins. Our data suggest that cytochrome c likely begins to unfold due to interior hydrophobic expansion, followed by α helical unfolding. This localization of structural changes is more specific than using CCS measurements alone.","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142811831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0