1
|
Lin J, Yun K, Sun Q, Xiang P, Wu L, Yang S, Dun J, Fu S, Chen H. How to sample a seizure plant: the role of the visualization spatial distribution analysis of Lophophora williamsii as an example. Forensic Sci Res 2023; 8:140-151. [PMID: 37621449 PMCID: PMC10445667 DOI: 10.1093/fsr/owad014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 05/16/2023] [Indexed: 08/26/2023] Open
Abstract
Natural compounds in plants are often unevenly distributed, and determining the best sampling locations to obtain the most representative results is technically challenging. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) can provide the basis for formulating sampling guideline. For a succulent plant sample, ensuring the authenticity and in situ nature of the spatial distribution analysis results during MSI analysis also needs to be thoroughly considered. In this study, we developed a well-established and reliable MALDI-MSI method based on preservation methods, slice conditions, auxiliary matrices, and MALDI parameters to detect and visualize the spatial distribution of mescaline in situ in Lophophora williamsii. The MALDI-MSI results were validated using liquid chromatography-tandem mass spectrometry. Low-temperature storage at -80°C and drying of "bookmarks" were the appropriate storage methods for succulent plant samples and their flower samples, and cutting into 40 μm thick sections at -20°C using gelatin as the embedding medium is the appropriate sectioning method. The use of DCTB (trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene]malononitrile) as an auxiliary matrix and a laser intensity of 45 are favourable MALDI parameter conditions for mescaline analysis. The region of interest semi-quantitative analysis revealed that mescaline is concentrated in the epidermal tissues of L. williamsii as well as in the meristematic tissues of the crown. The study findings not only help to provide a basis for determining the best sampling locations for mescaline in L. williamsii, but they also provide a reference for the optimization of storage and preparation conditions for raw plant organs before MALDI detection. Key Points An accurate in situ MSI method for fresh water-rich succulent plants was obtained based on multi-parameter comparative experiments.Spatial imaging analysis of mescaline in Lophophora williamsii was performed using the above method.Based on the above results and previous results, a sampling proposal for forensic medicine practice is tentatively proposed.
Collapse
Affiliation(s)
- Jiaman Lin
- School of Forensic Medicine, Shanxi Medical University, Key Laboratory of Forensic Medicine in Shanxi Province, Key Laboratory of Forensic Toxicology of Ministry of Public Security, Jinzhong, China
- Department of Forensic Toxicology, Shanghai Key Laboratory of Forensic Medicine, Academy of Forensic Science, Shanghai, China
| | - Keming Yun
- School of Forensic Medicine, Shanxi Medical University, Key Laboratory of Forensic Medicine in Shanxi Province, Key Laboratory of Forensic Toxicology of Ministry of Public Security, Jinzhong, China
| | - Qiran Sun
- Department of Forensic Toxicology, Shanghai Key Laboratory of Forensic Medicine, Academy of Forensic Science, Shanghai, China
| | - Ping Xiang
- Department of Forensic Toxicology, Shanghai Key Laboratory of Forensic Medicine, Academy of Forensic Science, Shanghai, China
| | - Lina Wu
- School of Forensic Medicine, Shanxi Medical University, Key Laboratory of Forensic Medicine in Shanxi Province, Key Laboratory of Forensic Toxicology of Ministry of Public Security, Jinzhong, China
- Department of Forensic Toxicology, Shanghai Key Laboratory of Forensic Medicine, Academy of Forensic Science, Shanghai, China
| | - Shuo Yang
- Department of Forensic Toxicology, Shanghai Key Laboratory of Forensic Medicine, Academy of Forensic Science, Shanghai, China
| | | | - Shanlin Fu
- School of Forensic Medicine, Shanxi Medical University, Key Laboratory of Forensic Medicine in Shanxi Province, Key Laboratory of Forensic Toxicology of Ministry of Public Security, Jinzhong, China
| | - Hang Chen
- Department of Forensic Toxicology, Shanghai Key Laboratory of Forensic Medicine, Academy of Forensic Science, Shanghai, China
| |
Collapse
|
2
|
Wamer N, Morse CN, Gadient JN, Dodson TA, Carlson EA, Prestwich EG. Comparison of Small Biomolecule Ionization and Fragmentation in Pseudomonas aeruginosa Using Common MALDI Matrices. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:355-365. [PMID: 36696681 PMCID: PMC9983012 DOI: 10.1021/jasms.2c00157] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 09/05/2022] [Accepted: 11/02/2022] [Indexed: 06/17/2023]
Abstract
Different bacterial cell surface associated biomolecules can be analyzed by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry and coupled with collision induced dissociation (CID) for identification. Pseudomonas aeruginosa is an opportunistic, Gram-negative bacterium that causes acute or chronic biofilm infections. Cells of P. aeruginosa communicate through a system of signaling biomolecules known as quorum sensing (QS). The QS system can result in the production of biosurfactant rhamnolipids known to associate and alter the cellular membrane. MALDI-TOF utilizes a variety of matrices that can interact differently with biomolecules for selective ionization. We examined six common matrices to determine the optimal matrix specific to different molecule classes in P. aeruginosa associated with cell surfaces. Three major molecule classes (quinolones, rhamnolipids, and phospholipids) were observed to ionize selectively with the different matrices tested. Sodiated and protonated adducts differed between matrices utilized in our study. Isobaric ions were identified as different molecule classes depending on the matrix used. We highlight the role of matrix selection in MALDI-TOF identification of molecules within a complex biological mixture.
Collapse
Affiliation(s)
- Nathan
C. Wamer
- Department
of Medicinal and Biological Chemistry, University
of Toledo, Toledo, Ohio 43606, United States
| | - Chase N. Morse
- Department
of Medicinal and Biological Chemistry, University
of Toledo, Toledo, Ohio 43606, United States
| | - Jennifer N. Gadient
- The
College of Natural Sciences and Mathematics, NSM Instrumentation Center, University of Toledo, Toledo, Ohio 43606, United States
| | - Taylor A. Dodson
- Department
of Medicinal and Biological Chemistry, University
of Toledo, Toledo, Ohio 43606, United States
| | - Eric A. Carlson
- Department
of Medicinal and Biological Chemistry, University
of Toledo, Toledo, Ohio 43606, United States
| | - Erin G. Prestwich
- Department
of Medicinal and Biological Chemistry, University
of Toledo, Toledo, Ohio 43606, United States
| |
Collapse
|
3
|
Exploring the structure and dynamics of macromolecular complexes by native mass spectrometry. J Proteomics 2020; 222:103799. [DOI: 10.1016/j.jprot.2020.103799] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 03/23/2020] [Accepted: 04/25/2020] [Indexed: 12/15/2022]
|
4
|
Thompson JW, Griffin ME, Hsieh-Wilson LC. Methods for the Detection, Study, and Dynamic Profiling of O-GlcNAc Glycosylation. Methods Enzymol 2017; 598:101-135. [PMID: 29306432 PMCID: PMC5886303 DOI: 10.1016/bs.mie.2017.06.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The addition of O-linked β-N-acetylglucosamine (O-GlcNAc) to serine/threonine residues of proteins is a ubiquitous posttranslational modification found in all multicellular organisms. Like phosphorylation, O-GlcNAc glycosylation (O-GlcNAcylation) is inducible and regulates a myriad of physiological and pathological processes. However, understanding the diverse functions of O-GlcNAcylation is often challenging due to the difficulty of detecting and quantifying the modification. Thus, robust methods to study O-GlcNAcylation are essential to elucidate its key roles in the regulation of individual proteins, complex cellular processes, and disease. In this chapter, we describe a set of chemoenzymatic labeling methods to (1) detect O-GlcNAcylation on proteins of interest, (2) monitor changes in both the total levels of O-GlcNAcylation and its stoichiometry on proteins of interest, and (3) enable mapping of O-GlcNAc to specific serine/threonine residues within proteins to facilitate functional studies. First, we outline a procedure for the expression and purification of a multiuse mutant galactosyltransferase enzyme (Y289L GalT). We then describe the use of Y289L GalT to modify O-GlcNAc residues with a functional handle, N-azidoacetylgalactosamine (GalNAz). Finally, we discuss several applications of the copper-catalyzed azide-alkyne cycloaddition "click" reaction to attach various alkyne-containing chemical probes to GalNAz and demonstrate how this functionalization of O-GlcNAc-modified proteins can be used to realize (1)-(3) above. Overall, these methods, which utilize commercially available reagents and standard protein analytical tools, will serve to advance our understanding of the diverse and important functions of O-GlcNAcylation.
Collapse
Affiliation(s)
- John W Thompson
- California Institute of Technology, Pasadena, CA, United States
| | | | | |
Collapse
|
5
|
Théberge R, Dikler S, Heckendorf C, Chui DHK, Costello CE, McComb ME. MALDI-ISD Mass Spectrometry Analysis of Hemoglobin Variants: a Top-Down Approach to the Characterization of Hemoglobinopathies. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:1299-310. [PMID: 26002792 PMCID: PMC4496427 DOI: 10.1007/s13361-015-1164-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Revised: 04/06/2015] [Accepted: 04/07/2015] [Indexed: 05/13/2023]
Abstract
Hemoglobinopathies are the most common inherited disorders in humans and are thus the target of screening programs worldwide. Over the past decade, mass spectrometry (MS) has gained a more important role as a clinical means to diagnose variants, and a number of approaches have been proposed for characterization. Here we investigate the use of matrix-assisted laser desorption/ionization time-of-flight MS (MALDI-TOF MS) with sequencing using in-source decay (MALDI-ISD) for the characterization of Hb variants. We explored the effect of matrix selection using super DHB or 1,5-diaminonaphthalene on ISD fragment ion yield and distribution. MALDI-ISD MS of whole blood using super DHB simultaneously provided molecular weights for the alpha and beta chains, as well as extensive fragmentation in the form of sequence defining c-, (z + 2)-, and y-ion series. We observed sequence coverage on the first 70 amino acids positions from the N- and C-termini of the alpha and beta chains in a single experiment. An abundant beta chain N-terminal fragment ion corresponding to βc34 was determined to be a diagnostic marker ion for Hb S (β6 Glu→Val, sickle cell), Hb C (β6 Glu→Lys), and potentially for Hb E (β26 Glu→Lys). The MALDI-ISD analysis of Hb S and HbSC yielded mass shifts corresponding to the variants, demonstrating the potential for high-throughput screening. Characterization of an alpha chain variant, Hb Westmead (α122 His→Gln), generated fragments that established the location of the variant. This study is the first clinical application of MALDI-ISD MS for the determination and characterization of hemoglobin variants.
Collapse
Affiliation(s)
- Roger Théberge
- Center for Biomedical Mass Spectrometry, Boston University School of Medicine, Boston, MA 02118
| | - Sergei Dikler
- Bruker Daltonics Inc., 40 Manning Road, Billerica, MA 01821
| | - Christian Heckendorf
- Center for Biomedical Mass Spectrometry, Boston University School of Medicine, Boston, MA 02118
| | - David H. K. Chui
- Department of Medicine, Boston University School of Medicine, Boston, MA 02118
| | - Catherine E. Costello
- Center for Biomedical Mass Spectrometry, Boston University School of Medicine, Boston, MA 02118
| | - Mark E. McComb
- Center for Biomedical Mass Spectrometry, Boston University School of Medicine, Boston, MA 02118
| |
Collapse
|
6
|
Boeri Erba E, Petosa C. The emerging role of native mass spectrometry in characterizing the structure and dynamics of macromolecular complexes. Protein Sci 2015; 24:1176-92. [PMID: 25676284 DOI: 10.1002/pro.2661] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 02/06/2015] [Accepted: 02/06/2015] [Indexed: 12/31/2022]
Abstract
Mass spectrometry (MS) is a powerful tool for determining the mass of biomolecules with high accuracy and sensitivity. MS performed under so-called "native conditions" (native MS) can be used to determine the mass of biomolecules that associate noncovalently. Here we review the application of native MS to the study of protein-ligand interactions and its emerging role in elucidating the structure of macromolecular assemblies, including soluble and membrane protein complexes. Moreover, we discuss strategies aimed at determining the stoichiometry and topology of subunits by inducing partial dissociation of the holo-complex. We also survey recent developments in "native top-down MS", an approach based on Fourier Transform MS, whereby covalent bonds are broken without disrupting non-covalent interactions. Given recent progress, native MS is anticipated to play an increasingly important role for researchers interested in the structure of macromolecular complexes.
Collapse
Affiliation(s)
- Elisabetta Boeri Erba
- Université Grenoble Alpes, Institut de Biologie Structurale (IBS), 71 Avenue des Martyrs, F-38044, Grenoble, France.,Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), DSV, IBS, F-38044, Grenoble, France.,Centre National de la Recherche Scientifique (CNRS), IBS, F-38044, Grenoble, France
| | - Carlo Petosa
- Université Grenoble Alpes, Institut de Biologie Structurale (IBS), 71 Avenue des Martyrs, F-38044, Grenoble, France.,Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), DSV, IBS, F-38044, Grenoble, France.,Centre National de la Recherche Scientifique (CNRS), IBS, F-38044, Grenoble, France
| |
Collapse
|
7
|
Classical MALDI-MS versus CE-based ESI-MS proteomic profiling in urine for clinical applications. Bioanalysis 2014; 6:247-66. [DOI: 10.4155/bio.13.313] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Human urine is an attractive and informative biofluid for medical diagnosis, which has been shown to reflect the (patho)-physiology of not only the urogenital system, but also others such as the cardiovascular system. For this reason, many studies have concentrated on the study of the urine proteome, aiming to find relevant biomarkers that could be applied in a clinical setting. However, this goal can only be achieved after reliable quantitative and qualitative analysis of the urinary proteome. In the last two decades, MS-based platforms have evolved to become indispensable tools for biomarker research. In this review, we will present and compare two of the most clinically relevant analytical platforms that have been used for the study of the urinary proteome, namely CE-based ESI-MS and classical MALDI-MS. These platforms, although not directly comparable, have been extensively used in proteomic profiling and therefore their comparison is fundamentally relevant to this field.
Collapse
|
8
|
Analysis of Mixture of Maltooligoses Using MALDI-TOFMS: Influence of Cationizing Agent Types. B KOREAN CHEM SOC 2009. [DOI: 10.5012/bkcs.2009.30.11.2806] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
9
|
Zhou LH, Kang GY, Kim KP. A binary matrix for improved detection of phosphopeptides in matrix-assisted laser desorption/ionization mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2009; 23:2264-2272. [PMID: 19551845 DOI: 10.1002/rcm.4139] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Application of matrix-assisted laser-desorption/ionization mass spectrometry (MALDI MS) to analysis and characterization of phosphopeptides in peptide mixtures may have a limitation, because of the lower ionizing efficiency of phosphopeptides than nonphosphorylated peptides in MALDI MS. In this work, a binary matrix that consists of two conventional matrices of 3-hydroxypicolinic acid (3-HPA) and alpha-cyano-4-hydroxycinnamic acid (CCA) was tested for phosphopeptide analysis. 3-HPA and CCA were found to be hot matrices, and 3-HPA not as good as CCA and 2,5-dihydroxybenzoic acid (DHB) for peptide analysis. However, the presence of 3-HPA in the CCA solution with a volume ratio of 1:1 could significantly enhance ion signals for phosphopeptides in both positive-ion and negative-ion detection modes compared with the use of pure CCA or DHB, the most common phosphopeptide matrices. Higher signal intensities of phosphopeptides could be obtained with lower laser power using the binary matrix. Neutral loss of the phosphate group (-80 Da) and phosphoric acid (-98 Da) from the phosphorylated-residue-containing peptide ions with the binary matrix was decreased compared with CCA alone. In addition, since the crystal shape prepared with the binary matrix was more homogeneous than that prepared with DHB, searching for 'sweet' spots can be avoided. The sensitivity to detect singly or doubly phosphorylated peptides in peptide mixtures was higher than that obtained with pure CCA and as good as that obtained using DHB. We also used the binary matrix to detect the in-solution tryptic digest of the crude casein extracted from commercially available low fat milk sample, and found six phosphopeptides to match the digestion products of casein, based on mass-to-charge values and LIFT TOF-TOF spectra.
Collapse
Affiliation(s)
- Li-Hua Zhou
- Department of Molecular Biotechnology, Konkuk University, Seoul 143-701, Korea
| | | | | |
Collapse
|
10
|
Fenyö D, Beavis RC. Informatics development: challenges and solutions for MALDI mass spectrometry. MASS SPECTROMETRY REVIEWS 2008; 27:1-19. [PMID: 17979143 DOI: 10.1002/mas.20152] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been successfully applied to elucidating biological questions trough the analysis of proteins, peptides, and nucleic acids. Here, we review the different approaches for analyzing the data that is generated by MALDI-MS. The first step in the analysis is the processing of the raw data to find peaks that correspond to the analytes. The peaks are characterized by their areas (or heights) and their centroids. The peak area can be used as a measure of the quantity of the analyte, and the centroid can be used to determine the mass of the analyte. The masses are then compared to models of the analyte, and these models are ranked according to how well they fit the data and their significance is calculated. This allows the determination of the identity (sequence and modifications) of the analytes. We show how this general data analysis workflow is applied to protein and nucleic acid chemistry as well as proteomics.
Collapse
Affiliation(s)
- David Fenyö
- The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
| | | |
Collapse
|
11
|
Giménez E, Benavente F, Barbosa J, Sanz-Nebot V. Towards a reliable molecular mass determination of intact glycoproteins by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2007; 21:2555-63. [PMID: 17639564 DOI: 10.1002/rcm.3109] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Different matrices and sample-matrix preparation procedures have been tested in order to study their influence on the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectra of intact glycoproteins, which present different degrees of glycosylation (human transferrin; bovine fetuin; bovine alpha(1)-acid-glycoprotein; recombinant human erythropoietin; and the novel erythropoiesis stimulating protein). Using sinapinic acid (SA) and the fast evaporation method, the studied glycoproteins became susceptible to fragmentation at any laser intensity, suggesting that this 'hot' matrix is unsuitable for a reliable molecular mass determination of glycosylated compounds. In contrast, 2,5-dihydroxybenzoic acid (DHB) and 6-aza-2-thiothymine (ATT), with an adequate sample-matrix preparation, provided improved results. Samples containing DHB after crystallization by vacuum drying demonstrated the best performance because the labile functional groups from the glycoforms were apparently fragmented to a lower extent. The average molecular masses obtained using this methodology were in all cases a better estimation than those values reported in the literature. The results were reproducible, and sensitivity was similar to that obtained with SA and the fast evaporation method. These excellent results suggest that this MALDI-TOF-MS methodology could be useful for an improved determination of the average molecular mass values of microheterogeneous compounds such as glycoproteins, glycosylated compounds or, in general, molecular mass values of molecules with similar labile functional groups.
Collapse
Affiliation(s)
- Estela Giménez
- Departament de Química Analítica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Spain
| | | | | | | |
Collapse
|
12
|
|
13
|
Schiller J, Süss R, Fuchs B, Müller M, Petković M, Zschörnig O, Waschipky H. The suitability of different DHB isomers as matrices for the MALDI-TOF MS analysis of phospholipids: which isomer for what purpose? EUROPEAN BIOPHYSICS JOURNAL: EBJ 2006; 36:517-27. [PMID: 17047951 DOI: 10.1007/s00249-006-0090-6] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2006] [Revised: 07/28/2006] [Accepted: 08/25/2006] [Indexed: 11/25/2022]
Abstract
Although the analysis of large biomolecules is the prime application of matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS), there is also increasing interest in lipid analysis. Since lipids possess relatively small molecular weights, matrix signals should be as small as possible to avoid overlap with lipid peaks. Although 2,5-dihydroxybenzoic acid (DHB) is an established MALDI matrix, the question whether just this isomer is ideal for lipid analysis was not yet addressed. UV absorptions of all six DHB isomers were determined and their laser desorption spectra recorded. In addition, all isomers were used as matrices to record positive and negative ion mass spectra of selected phospholipids (phosphatidylcholine and -serine): In the order 2,5-, 2,6-, 2,3- and 2,4-DHB, the quality of the positive ion lipid spectra decreases. This correlates well with the decreasing acidity of the applied DHB isomers. The 3,4- and 3,5- isomers give only very weak positive ion signals especially of acidic lipids. In contrast, the most suitable matrices in the negative ion mode are 2,5-, 2,4- and 3,5-DHB. 2,6-DHB does not provide any signal in the negative ion mode due to its marked acidity. Finally, differences in the crystallization behavior of the pure matrix and the matrix/lipid co-crystals were also monitored by atomic force microscopy (AFM): 2,5-DHB gave the smallest crystals and the skinniest layer. It is concluded that basically all DHB isomers can be used as MALDI matrices but the 2,5-isomer represents the most versatile compound.
Collapse
Affiliation(s)
- Jürgen Schiller
- Institute of Medical Physics and Biophysics, Medical Faculty, University of Leipzig, Leipzig, Germany.
| | | | | | | | | | | | | |
Collapse
|
14
|
Brancia FL, Bereszczak JZ, Lapolla A, Fedele D, Baccarin L, Seraglia R, Traldi P. Comprehensive analysis of glycated human serum albumin tryptic peptides by off-line liquid chromatography followed by MALDI analysis on a time-of-flight/curved field reflectron tandem mass spectrometer. JOURNAL OF MASS SPECTROMETRY : JMS 2006; 41:1179-85. [PMID: 16924599 DOI: 10.1002/jms.1083] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Glycated peptides arising from in vivo digestion of glycated proteins, usually called advanced glycation end (AGE) product peptides, are biologically relevant compounds due to their reactivity towards circulating and tissue proteins. To investigate their structures, in vitro glycation of human serum albumin (HSA) has been performed and followed by enzymatic digestion. Using different MALDI based approaches the digestion products obtained have been compared with those arising from enzymatic digestion of the protein. Results obtained using 2,5-dihydroxybenzoic acid (DHB) indicate this as the most effective matrix, leading to an increase in the coverage of the glycated protein. Off-line microbore liquid chromatography prior to MALDI analysis reveals that 63% of the free amino groups amenable to glycation are modified. In addition, the same approach shows the co-presence of underivatised peptides. This indicates that, regardless of the high glucose concentration employed for HSA incubation, glycation does not go to completion. Tandem mass spectrometric data suggest that the collision induced dissociation of singly charged glycated peptides leads to specific fragmentation pathways related to the condensed glucose molecule. The specific neutral losses derived from the activated glycated peptides can be used as signature for establishing the occurrence of glycation processes.
Collapse
|
15
|
Cindrić M, Galić N, Vuletić M, Klarić M, Drevenkar V. Evaluation of recombinant human interferon α-2b structure and stability by in-gel tryptic digestion, H/D exchange and mass spectrometry. J Pharm Biomed Anal 2006; 40:781-7. [PMID: 16316735 DOI: 10.1016/j.jpba.2005.10.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2005] [Revised: 10/18/2005] [Accepted: 10/20/2005] [Indexed: 11/23/2022]
Abstract
Stability and structure of recombinant interferon alpha-2b (rHuINF alpha-2b) was studied by mass spectrometry (MALDI-TOF and Q-TOF MS), chromatography (LC-UV-FLD-DAD, LC-MS) and CD spectroscopy. Besides analysis of the substance according to Ph. Eur. methods, two additional mass spectrometric methods were developed. The aim of both methods was to estimate structure-stability relationship connected to methionine oxidation or protein degradation. Preservation or degradation of protein structure was confirmed by H/D exchange in four separate experiments. Kinetics of deuterium incorporation into macromolecule was monitored over 2670 min. Isoforms of rHuINF alpha-2b were separated by 2D gel electrophoresis. In-gel digestion with trypsin and mass spectrometric analysis, performed on four separated isoforms at the mass corresponding to the mass of rHuINF alpha-2b with oxidized methionines, confirmed oxidation of all methionines to a different extent. Another four isoforms observed in 2D gel are most likely dimers of the same macromolecules with scrambled disulphide bridges. Oxidation and dimerisation are consequences of protein interaction with oxidizing reagents in polyacrilamide gel.
Collapse
Affiliation(s)
- Mario Cindrić
- PLIVA, Research & Development Ltd., Prilaz Baruna Filipovića 29, 10000 Zagreb, Croatia.
| | | | | | | | | |
Collapse
|
16
|
Dashtiev M, Frankevich V, Zenobi R. Signal enhancement in matrix-assisted laser desorption/ionization by doping with Cu(II) chloride. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2005; 19:289-291. [PMID: 15609376 DOI: 10.1002/rcm.1768] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
|
17
|
Muralidharan V, Cho J, Trester-Zedlitz M, Kowalik L, Chait BT, Raleigh DP, Muir TW. Domain-specific incorporation of noninvasive optical probes into recombinant proteins. J Am Chem Soc 2004; 126:14004-12. [PMID: 15506763 DOI: 10.1021/ja0466199] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An integrated approach is described that allows the domain-specific incorporation of optical probes into large recombinant proteins. The strategy is the combination of two existing techniques, expressed protein ligation (EPL) and in vivo amino acid replacement of tryptophans with tryptophan (Trp) analogues. The Src homology 3 (SH3) domain from the c-Crk-I adaptor protein has been labeled with a Trp analogue, 7-azatryptophan (7AW), using Escherichia coli Trp auxotrophs. Structural, biochemical, and thermodynamic studies show that incorporation of 7AW does not significantly perturb the structure or function of the isolated domain. Ligation of the 7AW-labeled SH3 domain to the c-Crk-I Src homology 2 (SH2) domain, via EPL, generated the multidomain protein, c-Crk-I, with a domain-specific label. Studies of this labeled protein show that the biochemical and thermodynamic properties of the SH3 domain do not change within the context of a larger multidomain protein. The technology described here is likely to be a useful tool in enhancing our understanding of the behavior of modular domains in their natural context, within multidomain proteins.
Collapse
Affiliation(s)
- Vasant Muralidharan
- Laboratory of Synthetic Protein Chemistry, The Rockefeller University, New York, New York 10021, USA
| | | | | | | | | | | | | |
Collapse
|
18
|
Determination of neutral oligosaccharides in vegetables by matrix-assisted laser desorption/ionization mass spectrometry. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2004.04.030] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
19
|
Kim HS, Hoja U, Stolz J, Sauer G, Schweizer E. Identification of the tRNA-binding protein Arc1p as a novel target of in vivo biotinylation in Saccharomyces cerevisiae. J Biol Chem 2004; 279:42445-52. [PMID: 15272000 DOI: 10.1074/jbc.m407137200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Biotin is an essential cofactor of cell metabolism serving as a protein-bound coenzyme in ATP-dependent carboxylation, in transcarboxylation, and certain decarboxylation reactions. The involvement of biotinylated proteins in other cellular functions has been suggested occasionally, but available data on this are limited. In the present study, a Saccharomyces cerevisiae protein was identified that reacts with streptavidin on Western blots and is not identical to one of the known biotinylated yeast proteins. After affinity purification on monomeric avidin, the biotinylated protein was identified as Arc1p. Using 14C-labeled biotin, the cofactor was shown to be incorporated into Arc1p by covalent and alkali-stable linkage. Similar to the known carboxylases, Arc1p biotinylation is mediated by the yeast biotin:protein ligase, Bpl1p. Mutational studies revealed that biotinylation occurs at lysine 86 within the N-terminal domain of Arc1p. In contrast to the known carboxylases, however, in vitro biotinylation of Arc1p is incomplete and increases with BPL1 overexpression. In accordance to this fact, Arc1p lacks the canonical consensus sequence of known biotin binding domains, and the bacterial biotin:protein ligase, BirA, is unable to use Arc1p as a substrate. Arc1p was shown previously to organize the association of MetRS and GluRS tRNA synthetases with their cognate tRNAs thereby increasing the substrate affinity and catalytic efficiency of these enzymes. Remarkably, not only biotinylated but also the biotin-free Arc1p obtained by replacement of lysine 86 with arginine were capable of restoring Arc1p function in both arc1Delta and arc1Deltalos1Delta mutants, indicating that biotinylation of Arc1p is not essential for activity.
Collapse
Affiliation(s)
- Hyun Soo Kim
- Lehrstuhl für Biochemie der Universität Erlangen-Nürnberg, Erlangen D-91058, Germany
| | | | | | | | | |
Collapse
|
20
|
Cindrić M, Vuletić M. Characterisation of interferon α-2b by liquid chromatography and mass spectrometry techniques. J Sep Sci 2003. [DOI: 10.1002/jssc.200301419] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
21
|
He Y, Zhong W, Yeung ES. Multiplexed on-column protein digestion and capillary electrophoresis for high-throughput comprehensive peptide mapping. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 782:331-41. [PMID: 12458016 DOI: 10.1016/s1570-0232(02)00698-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A novel scheme based on multiplexed capillary electrophoresis (CE) has been developed for high-throughput, low-cost and comprehensive peptide mapping. Orthogonal peptide maps of the protein of interest were obtained by using multiple reaction conditions with three different enzymes (trypsin, pepsin, and chymotrypsin), and multiple separation conditions with six zone electrophoresis buffers and two micellar electrokinetic chromatography (MEKC) buffers. Fifteen nanoliters of two protein samples (beta-lactoglobulin A and beta-lactoglobulin B) were separately mixed on-column and digested independently at 37 degrees C for 10 min to produce peptides in a 20-capillary system. The resulting peptides were detected simultaneously at 214 nm by a photodiode array detector. The overall analysis time from reaction to detection was about 40 min.
Collapse
Affiliation(s)
- Yan He
- Ames Laboratory, US Department of Energy, Iowa 50011, USA
| | | | | |
Collapse
|
22
|
Liu T, Li JD, Zeng R, Shao XX, Wang KY, Xia QC. Capillary electrophoresis-electrospray mass spectrometry for the characterization of high-mannose-type N-glycosylation and differential oxidation in glycoproteins by charge reversal and protease/glycosidase digestion. Anal Chem 2001; 73:5875-85. [PMID: 11791556 DOI: 10.1021/ac0106748] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The characterization of high-mannose-type N-glycosylation by capillary electrophoresis-electrospray mass spectrometry (CE-ESI MS) was described. In addition to the use of a cationic noncovalent capillary coating, strong acidic buffer, and charge reversal to increase the glycoform resolving power, N-glycosidase F (PNGase F) combined with a basic protease and alpha-mannosidase combined with an acidic protease were used to analyze the high-mannose-type N-glycosylation in ribonuclease B (RNase B) and in a novel C-type lectin from the venom of Trimeresurus stejnegeri (TSL). The structures of oligosaccharide, glycosylation sites, and glycoform distributions were determined simultaneously, and the differential oxidation of Met residues in glycopeptides obtained from TSL protease digestion was also characterized successfully by CE-MS/MS. The results showed that the oligosaccharide attached to RNase B has a structure of GlcNAc2Man5 approximately 9, and that attached to TSL has a structure of GlcNAc2Min5 approximately 8. The glycoform distributions in these glycoproteins are quite different, with the GlcNAc2Man5 type predominant in RNase B, and the GlcNAc2Man8 type, in TSL This method may be useful not only for the characterization of glycosylation sites and glycan structures, but also for the determination of the relative abundance of individual glycoforms.
Collapse
Affiliation(s)
- T Liu
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, People's Republic of China
| | | | | | | | | | | |
Collapse
|
23
|
Jiang Q, Taupenot L, Mahata SK, Mahata M, O'Connor DT, Miles LA, Parmer RJ. Proteolytic cleavage of chromogranin A (CgA) by plasmin. Selective liberation of a specific bioactive CgA fragment that regulates catecholamine release. J Biol Chem 2001; 276:25022-9. [PMID: 11342539 DOI: 10.1074/jbc.m101545200] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chromogranin A (CgA), the major soluble protein in catecholamine storage vesicles, serves as a prohormone that is cleaved into bioactive peptides that inhibit catecholamine release, providing an autocrine, negative feedback mechanism for regulating catecholamine responses during stress. However, the proteases responsible for the processing of CgA and release of bioactive peptides have not been established. Recently, we found that chromaffin cells express components of the plasmin(ogen) system, including tissue plasminogen activator, which is targeted to catecholamine storage vesicles and released with CgA and catecholamines in response to sympathoadrenal stimulation, and high affinity cell surface receptors for plasminogen, to promote plasminogen activation at the cell surface. In the present study, we investigated processing of CgA by plasmin and sought to identify specific bioactive CgA peptides produced by plasmin proteolysis. Highly purified human CgA (hCgA) was produced by expression in Escherichia coli and purification using metal affinity chromatography. hCgA was digested with plasmin. Matrix-assisted laser desorption/ionization mass spectrometry identified a major peptide produced with a mass/charge ratio (m/z) of 1546, corresponding uniquely to hCgA-(360-373), the identity of which was confirmed by reverse phase high pressure liquid chromatography and amino-terminal microsequencing. hCgA-(360-373) was selectively liberated by plasmin from hCgA at early time points and was stable even after prolonged exposure to plasmin. The corresponding synthetic peptide markedly inhibited nicotine-induced catecholamine release from pheochromocytoma cells. These results identify plasmin as a protease, present in the local environment of the chromaffin cell, that selectively cleaves CgA to generate a bioactive fragment, hCgA-(360-373), that inhibits nicotinic-mediated catecholamine release. These results suggest that the plasminogen/plasmin system through its interaction with CgA may play a major role in catecholaminergic function and suggest a specific mechanism as well as a discrete CgA peptide through which this effect is mediated.
Collapse
Affiliation(s)
- Q Jiang
- Department of Medicine, University of California-San Diego, 3350 La Jolla Village Dr., San Diego, CA 92161, USA
| | | | | | | | | | | | | |
Collapse
|
24
|
Gao J, Xu J, Locascio LE, Lee CS. Integrated microfluidic system enabling protein digestion, peptide separation, and protein identification. Anal Chem 2001; 73:2648-55. [PMID: 11403312 DOI: 10.1021/ac001126h] [Citation(s) in RCA: 214] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An integrated platform is presented for rapid and sensitive protein identification by on-line protein digestion and analysis of digested proteins using electrospray ionization mass spectrometry or transient capillary isotachophoresis/capillary zone electrophoresis with mass spectrometry detection. A miniaturized membrane reactor is constructed by fabricating the microfluidic channels on a poly(dimethylsiloxane) substrate and coupling the microfluidics to a poly(vinylidene fluoride) porous membrane with the adsorbed trypsin. On the basis of he large surface area-to-volume ratio of porous membrane media, adsorbed trypsin onto the poly(vinylidene fluoride) membrane is employed for achieving ultrahigh catalytic turnover. The extent of protein digestion in a miniaturized membrane reactor can be directly controlled by the residence time of protein analytes inside the trypsin-adsorbed membrane, the reaction temperature, and the protein concentration. The resulting peptide mixtures can either be directly analyzed using electrospray ionization mass spectrometry or further concentrated and resolved by electrophoretic separations prior to the mass spectrometric analysis. This microfluidic system enables rapid identification of proteins in minutes instead of hours, consumes very little sample (nanogram or less), and provides on-line interface with upstream protein separation schemes for the analysis of complex protein mixtures such as cell lysates.
Collapse
Affiliation(s)
- J Gao
- Department of Chemistry and Biochemistry, University of Maryland, College Park 20742, USA
| | | | | | | |
Collapse
|
25
|
Henzel WJ, Stults JT. Matrix-assisted laser desorption/ionization time-of-flight mass analysis of peptides. CURRENT PROTOCOLS IN PROTEIN SCIENCE 2001; Chapter 16:Unit 16.2. [PMID: 18429129 DOI: 10.1002/0471140864.ps1602s04] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is one of the most useful techniques for determining the mass of biomolecules, with exceptional capabilities for mass analysis of peptides. Relative to other ionization techniques, it provides high sensitivity and excellent tolerance of salt and other common buffer components. Routine detection limits for peptides are in the subpicomole range. The ions commonly observed are the protonated molecules (M+H(+)), which makes data analysis relatively easy. This overview discusses instrument configuration and calibration, sample preparation, along with specific approaches for analyzing peptide mixtures, synthetic peptides, and chemical modifications of peptides.
Collapse
Affiliation(s)
- W J Henzel
- Genentech, Inc., South San Francisco, California, USA
| | | |
Collapse
|
26
|
Jankowski J, Stephan N, Knobloch M, Fischer S, Schmaltz D, Zidek W, Schlüter H. Mass-spectrometry-linked screening of protein fractions for enzymatic activities--a tool for functional genomics. Anal Biochem 2001; 290:324-9. [PMID: 11237335 DOI: 10.1006/abio.2001.5001] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A simple and rapid strategy is described to screen protein fractions for defined enzymatic activity. A protein fraction from a porcine kidney extract was immobilized by covalent coupling to activated affinity beads. The immobilized proteins were incubated with probes specific for different enzyme activities. The reaction products were analyzed by matrix-assisted laser desorption/ionization (MALDI)-mass spectrometry. The MALDI spectra indicate the presence of 5'-nucleotidase, phosphatase, kinase, glutathione reductase, and renin activities in the kidney protein extract. Furthermore, the method can be used to screen for inhibitors of enzymatic reactions. The method is adaptable to high-throughput sample handling and automated mass spectrometric analysis and therefore suited for functional genomics.
Collapse
Affiliation(s)
- J Jankowski
- Medizinische Klinik IV, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Hindenburgdamm 30, 12200 Berlin, Germany
| | | | | | | | | | | | | |
Collapse
|
27
|
Tsarbopoulos A, Varnerin J, Cannon-Carlson S, Wylie D, Pramanik B, Tang J, Nagabhushan TL. Mass spectrometric mapping of disulfide bonds in recombinant human interleukin-13. JOURNAL OF MASS SPECTROMETRY : JMS 2000; 35:446-453. [PMID: 10767776 DOI: 10.1002/(sici)1096-9888(200003)35:3<446::aid-jms956>3.0.co;2-o] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Interleukin 13 (IL-13), a member of the a-helical family of cytokines, has approximately 30% primary sequence homology with IL-4 and shares a common receptor component. The biologically active rhIL-13 is monomeric and non-glycosylated, and contains two disulfide bonds as determined by comparative electrospray mass spectrometric (MS) analysis of the protein before and after reduction with dithiothreitol-dithioerythritol. A trypsin-resistant core peptide of rhIL-13 was isolated and analyzed by plasma desorption (PD) MS, identifying a disulfide-linked core peptide. Subsequent digestion of this core peptide by pepsin, followed by PDMS analysis of the resulting cystine-containing peptic fragments, provided rapid determination of the existing disulfide bonds between cysteine residues 28-56 and 44-70. This disulfide arrangement is similar to that observed for the analogous four internal cysteine residues in hIL-4. The conservation of disulfide bond arrangements between hIL-13 and hIL-4, coupled with their alpha-helical structure and sequence homologies, confirms that IL-13 and IL-4 are structural homologues. It is also consistent with their reported similarities in biological function and receptor binding kinetics.
Collapse
Affiliation(s)
- A Tsarbopoulos
- Department of Bioisolation Process Development, Schering-Plough Research Institute, Union, New Jersey 07083, USA.
| | | | | | | | | | | | | |
Collapse
|
28
|
Vassileva-Atanassova A, Niwa T, Mironova R, Ivanov I. Mass-spectral analysis of human interferon-gamma and chloramphenicol acetyltransferase I produced in two Escherichia coli strains. J Biotechnol 2000; 78:61-7. [PMID: 10702911 DOI: 10.1016/s0168-1656(99)00236-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Recombinant human interferon-gamma and chloramphenicol acetyltransferase I were isolated from two Escherichia coli strains, E. coli LE329 and E. coli XL1-blue and characterized by electrospray ionization mass spectrometry (ESI-MS). The ESI-MS analysis showed higher masses in comparison with the theoretically calculated for both proteins as well as unexpected molecular heterogeneity. The ESI-MS spectral patterns of the proteins depended on the host strain used and were more heterogenous for the proteins isolated from E. coli LE392. One of the proteins (human interferon-gamma obtained from E. coli XL1-blue) was further subjected to BrCN cleavage. The ESI-MS analysis of the polypeptide mixture revealed shift in the molecular mass for two peptides including the last 26 amino acids of the human interferon-gamma molecule.
Collapse
|
29
|
Kalume DE, Stenflo J, Czerwiec E, Hambe B, Furie BC, Furie B, Roepstorff P. Structure determination of two conotoxins from Conus textile by a combination of matrix-assisted laser desorption/ionization time-of-flight and electrospray ionization mass spectrometry and biochemical methods. JOURNAL OF MASS SPECTROMETRY : JMS 2000; 35:145-156. [PMID: 10679974 DOI: 10.1002/(sici)1096-9888(200002)35:2<145::aid-jms922>3.0.co;2-i] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Two highly modified conotoxins from the mollusc Conus textile, epsilon-TxIX and Gla(1)-TxVI, were characterized by matrix-assisted laser desorption/ionization and electrospray mass spectrometry and also by electrospray ionization tandem and triple mass spectrometry in combination with enzymatic cleavage and chemical modification reactions. The mass spectrometric studies allowed the confirmation of the sequence determined by Edman degradation and assignment of unidentified amino acid residues, among which bromotryptophan residues and an O-glycosylated threonine residue were observed. Methyl esterification was found necessary for the site-specific assignment of the Gla residues in the peptides.
Collapse
Affiliation(s)
- D E Kalume
- Department of Molecular Biology, University of Southern Denmark, Odense University, Campusvej 55, DK-5230 Odense M, Denmark
| | | | | | | | | | | | | |
Collapse
|
30
|
Ekström S, Onnerfjord P, Nilsson J, Bengtsson M, Laurell T, Marko-Varga G. Integrated microanalytical technology enabling rapid and automated protein identification. Anal Chem 2000; 72:286-93. [PMID: 10658321 DOI: 10.1021/ac990731l] [Citation(s) in RCA: 186] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protein identification through peptide mass mapping by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has become a standard technique, used in many laboratories around the world. The traditional methodology often includes long incubations (6-24 h) and extensive manual steps. In an effort to address this, an integrated microanalytical platform has been developed for automated identification of proteins. The silicon micromachined analytical tools, i.e., the microchip immobilized enzyme reactor (mu-chip IMER), the piezoelectric microdispenser, and the high-density nanovial target plates, are the cornerstones in the system. The mu-chip IMER provides on-line enzymatic digestion of protein samples (1 microL) within 1-3 min, and the microdispenser enables subsequent on-line picoliter sample preparation in a high-density format. Interfaced to automated MALDI-TOF MS, these tools compose a highly efficient platform that can analyze 100 protein samples in 3.5 h. Kinetic studies on the microreactors are reported as well as the operation of this microanalytical platform for protein identification, wherein lysozyme, myoglobin, ribonuclease A, and cytochrome c have been identified with a high sequence coverage (50-100%).
Collapse
Affiliation(s)
- S Ekström
- Department of Cell and Molecular Biology, Lund University, Sweden
| | | | | | | | | | | |
Collapse
|
31
|
Abstract
This review describes the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to carbohydrate analysis and covers the period 1991-1998. The technique is particularly valuable for carbohydrates because it enables underivatised, as well as derivatised compounds to be examined. The various MALDI matrices that have been used for carbohydrate analysis are described, and the use of derivatization for improving mass spectral detection limits is also discussed. Methods for sample preparation and for extracting carbohydrates from biological media prior to mass spectrometric analysis are compared with emphasis on highly sensitive mass spectrometric methods. Quantitative aspects of MALDI are covered with respect to the relationship between signal strength and both mass and compound structure. The value of mass measurements by MALDI to provide a carbohydrate composition is stressed, together with the ability of the technique to provide fragmentation spectra. The use of in-source and post-source decay and collision-induced fragmentation in this context is described with emphasis on ions that provide information on the linkage and branching patterns of carbohydrates. The use of MALDI mass spectrometry, linked with exoglycosidase sequencing, is described for N-linked glycans derived from glycoproteins, and methods for the analysis of O-linked glycans are also covered. The review ends with a description of various applications of the technique to carbohydrates found as constituents of glycoproteins, bacterial glycolipids, sphingolipids, and glycolipid anchors.
Collapse
Affiliation(s)
- D J Harvey
- Oxford Glycobiology Institute, Department of Biochemistry, UK.
| |
Collapse
|
32
|
Nigou J, Gilleron M, Brando T, Vercellone A, Puzo G. Structural definition of arabinomannans from Mycobacterium bovis BCG. Glycoconj J 1999; 16:257-64. [PMID: 10579694 DOI: 10.1023/a:1007046609341] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The structures of the hydrophilic parietal and cellular arabinomannans isolated from Mycobacterium bovis BCG cell wall [Nigou et al. (1997) J Biol Chem 272: 23094-103] were investigated. Their molecular mass as determined by MALDI-TOF mass spectrometry was around 16 kDa. Concerning cap structure, capillary electrophoresis analysis demonstrated that dimannoside (Manpalpha1-->2Manp) was the most abundant motif (65-75%). Using two-dimensional 1H-13C NMR spectroscopy, the mannan core was unambiguously demonstrated to be composed of -->6Manpalpha1--> backbone substituted at some O-2 by a single Manp unit. The branching degree was determined as 84%. Finally, arabinomannans were found to be devoid of the phosphatidyl-myo-inositol anchor and, by aminonaphthalene disulfonate tagging, the mannan core was shown to contain a reducing end. This constitutes the main difference between arabinomannans and lipoarabinomannans from Mycobacterium bovis BCG.
Collapse
Affiliation(s)
- J Nigou
- Institut de Pharmacologie et de Biologie Structurale du Centre National de la Recherche Scientifique, UPR 9062, Toulouse, France
| | | | | | | | | |
Collapse
|
33
|
Jeyarajah S, Parker CE, Summer MT, Tomer KB. Matrix-assisted laser desorption ionization/mass spectrometry mapping of human immunodeficiency virus-gp120 epitopes recognized by a limited polyclonal antibody. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 1998; 9:157-165. [PMID: 9679595 DOI: 10.1016/s1044-0305(97)00247-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In this study we have applied epitope excision and epitope extraction strategies, combined with matrix assisted laser desorption/ionization mass spectrometry, to determine the fine structure of epitopes recognized by a polyclonal antibody to human immunodeficiency virus envelope glycoprotein gp120. This is the first application of this approach to epitope mapping on a large, heavily glycosylated protein. In the epitope excision method, gp120 in the native form is first bound to the antibody immobilized on sepharose beads and cleaved with endoproteinase enzymes. In the epitope extraction method, the gp120 was first proteolytically cleaved and then allowed to react with the immobilized antibody. The fragments that remain bound to the antibody, after repeated washing to remove the unbound peptides, contain the antigenic region that is recognized by the antibody, and the bound peptides in both methods can be characterized by direct analysis of the immobilized antibody by matrix assisted laser desorption ionization/mass spectrometry. In this study we have carried out epitope excision and extraction experiments with three different enzymes and have identified residues 472-478 as a major epitope. In addition, antigenic regions containing minor epitopes have also been identified.
Collapse
Affiliation(s)
- S Jeyarajah
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | | | | | | |
Collapse
|
34
|
Wiekowski M, Prosser D, Taremi S, Tsarbopoulos A, Jenh CH, Chou CC, Lundell D, Zavodny P, Narula S. Characterization of potential antagonists of human interleukin 5 demonstrates their cross-reactivity with receptors for interleukin 3 and granulocyte-macrophage colony-stimulating factor. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 246:625-32. [PMID: 9219518 DOI: 10.1111/j.1432-1033.1997.t01-2-00625.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The ligand-binding alpha-chain of the human interleukin 5 (IL-5) receptor was expressed in its soluble form, lacking the transmembrane and cytoplasmic domains, from recombinant baculovirus. The soluble receptor was used in a scintillation proximity assay to identify two chemical compounds that inhibit binding of human IL-5 to the soluble receptor alpha chain with IC50 of 8 microM and 11 microM. These compounds also inhibited the interaction of human IL-5 with its membrane-bound receptor, composed of the ligand-binding alpha chain and signal-transducing beta chain, and prevented signaling through the receptor. Analysis by surface plasmon resonance and matrix-assisted laser-desorption/ionization mass spectrometry showed that the identified compounds bound irreversibly to the receptor at a 1:1 (mol/mol) ratio, suggesting a covalent interaction with the alpha chain of the human IL-5 receptor. Both compounds also inhibited the interaction of the receptors for interleukin 3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF), which are involved in hematopoietic differentiation and activation of immune cells, thus eliminating them as potential therapeutic agents. The inhibition of the structurally closely related receptors for IL-5, IL-3 and GM-CSF by both compounds, while binding of interleukin-4 to its receptor was not affected, suggests that a similar reactive site exists in the ligand-binding domains of the receptors for IL-5, IL-3 and GM-CSF.
Collapse
MESH Headings
- Animals
- Antigens, CD/metabolism
- Biosensing Techniques
- Cell Division/drug effects
- Cross Reactions
- Granulocyte-Macrophage Colony-Stimulating Factor/antagonists & inhibitors
- Granulocyte-Macrophage Colony-Stimulating Factor/metabolism
- Humans
- Interleukin-3/metabolism
- Interleukin-5/antagonists & inhibitors
- Interleukin-5/metabolism
- Mice
- Phenols/pharmacology
- Piperidines/pharmacology
- Receptors, Interleukin/antagonists & inhibitors
- Receptors, Interleukin/metabolism
- Receptors, Interleukin-3/antagonists & inhibitors
- Receptors, Interleukin-3/metabolism
- Receptors, Interleukin-4
- Receptors, Interleukin-5
- Recombinant Proteins/metabolism
- Solubility
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Spodoptera
- Thiazoles/pharmacology
- Tumor Cells, Cultured
Collapse
Affiliation(s)
- M Wiekowski
- Department of Immunology, Schering Plough Research Institute, Kenilworth, NJ 07033, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Winkler MA, Kundu S, Robey TE, Robey WG. Comparative peptide mapping of a hepatitis C viral recombinant protein by capillary electrophoresis and matrix-assisted laser desorption time-of-flight mass spectrometry. J Chromatogr A 1996; 744:177-85. [PMID: 8843666 DOI: 10.1016/0021-9673(96)00184-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Capillary electrophoresis (CE) and matrix assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF-MS) were investigated as alternatives to sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis for peptide mapping with Staphylococcus aureus protease (V8) of a hydrophobic recombinant hepatitis C virus antigen, HC-31, which required 0.1% SDS for solubility. Controls (V8 only) or HC-31 digests were extracted with chloroform-methanol-water (1:4:3) to remove SDS, which interferes with MALDI-TOF, and high salt content, which affects CE. In two different runs by CE, the elution times of each of 11 peptide peaks were very reproducible (R.S.D. < 0.016). 25 fragments were resolved by MALDI-TOF-MS, including six smaller peptides (M(r) < 13 000) resulting from V8 autodigestion. MALDI-TOF-MS indicated that partial cleavages occurred, primarily at sites where there are paired glutamic and/or aspartic acid residues.
Collapse
Affiliation(s)
- M A Winkler
- Diagnostics Division, Abbott Laboratories, North Chicago, II 60064, USA
| | | | | | | |
Collapse
|
36
|
Akashi S, Noguchi K, Yuji R, Tagami U, Hirayama K, Kato K, Kim H, Tokioka K, Shimada I, Arata Y. Characterization of mouse switch variant antibodies by matrix-assisted laser desorption ionization mass spectrometry and electrospray ionization mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 1996; 7:707-721. [PMID: 24203564 DOI: 10.1016/1044-0305(96)80517-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/1995] [Revised: 02/19/1996] [Accepted: 03/03/1996] [Indexed: 06/02/2023]
Abstract
The amino acid sequences of mouse monoclonal antibodies have been characterized completely by mass spectrometry. Antibodies used in the present study were derived from mouse switch variant cell lines that produce four kinds of immunoglobulin Gs (IgGs). The amino acid sequences of these antibodies had not been estimated from the corresponding DNA sequence, so the sequences of IgGs derived from other strains were used as references in this study. Intra- and interchain disulfide bonds of the IgGs were reduced and carboxymethylated and the products were subjected to proteolytic digestion. The existence of N-linked oligosaccharides also was taken into account. The capabilities and limitations of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry and capillary liquid chromatography-electrospray ionization mass spectrometry are discussed in the structural characterization of the antibodies. Based on our results, allotypes of the antibodies examined are discussed. This study shows that amino acid sequences of proteins, such as IgG, can be investigated without information about the corresponding DNA sequence if appropriate reference sequences derived from other strains can be used.
Collapse
Affiliation(s)
- S Akashi
- Central Research Laboratories, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, 210, Kawasaki, Kanagawa, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Harmon BJ, Gu X, Wang DI. Rapid monitoring of site-specific glycosylation microheterogeneity of recombinant human interferon-gamma. Anal Chem 1996; 68:1465-73. [PMID: 8815742 DOI: 10.1021/ac951229d] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
An analytical system is presented for rapid assessment of site-specific microheterogeneity of the two potential N-linked glycosylation sites of recombinant human interferon-gamma (IFN-gamma) derived from Chinese hamster ovary cell culture. The target protein is first purified from culture supernatant by immunoaffinity chromatography, and the acidic eluent is neutralized via an in-line mixing tee. On-line proteolysis is rapidly performed by an immobilized trypsin cartridge, and reversed-phase chromatography isolates the two pools of glycopeptides representing the potential glycosylation sites. Following off-line analysis by matrix-assisted laser-desorption ionization/time-of-flight (MALDI/TOF) mass spectrometry, observed mass shifts of glycopeptides relative to the known masses of their amino acid portions are correlated to site-specific oligosaccharide structures. Desialylation of glycopeptides by sialidase treatment on the MALDI sample plate allows for quantitative estimations of asialoglycan structures by MALDI/TOF. This methodology permits glycoprotein microheterogeneity to be evaluated in a time frame of approximately 2 h, utilizing as little as 0.5 microgram (25 pmol) of product. Results of monitoring a batch culture are presented as well as analysis of a culture containing deoxymannojirimycin, an inhibitor of glycoprotein processing.
Collapse
Affiliation(s)
- B J Harmon
- Biotechnology Process Engineering Center, Massachusetts Institute of Technology, Cambridge 02139-4308, USA
| | | | | |
Collapse
|
38
|
Andersen JS, Svensson B, Roepstorff P. Electrospray ionization and matrix assisted laser desorption/ionization mass spectrometry: powerful analytical tools in recombinant protein chemistry. Nat Biotechnol 1996; 14:449-57. [PMID: 9630919 DOI: 10.1038/nbt0496-449] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Electrospray ionization and matrix assisted laser desorption/ionization are effective ionization methods for mass spectrometry of biomolecules. Here we describe the capabilities of these methods for peptide and protein characterization in biotechnology. An integrated analytical strategy is presented encompassing protein characterization prior to and after cloning of the corresponding gene.
Collapse
Affiliation(s)
- J S Andersen
- Department of Molecular Biology, Odense University, Denmark
| | | | | |
Collapse
|
39
|
James DC, Goldman MH, Hoare M, Jenkins N, Oliver RW, Green BN, Freedman RB. Posttranslational processing of recombinant human interferon-gamma in animal expression systems. Protein Sci 1996; 5:331-40. [PMID: 8745411 PMCID: PMC2143336 DOI: 10.1002/pro.5560050217] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We have characterized the heterogeneity of recombinant human interferon-gamma (IFN-gamma) produced by three expression systems: Chinese hamster ovary cells, the mammary gland of transgenic mice, and baculovirus-infected Spodopera frugiperda (Sf9) insect cells. Analyses of whole IFN-gamma proteins by electrospray ionization-mass spectrometry (ESI-MS) from each recombinant source revealed heterogeneous populations of IFN-gamma molecules resulting from variations in N-glycosylation and C-terminal polypeptide cleavages. A series of more specific analyses assisted interpretation of maximum entropy deconvoluted ESI-mass spectra of whole IFN-gamma proteins; MALDI-MS analyses of released, desialylated N-glycans and of deglycosylated IFN-gamma polypeptides were combined with analyses of 2-aminobenzamide labeled sialylated N-glycans by cation-exchange high-performance liquid chromatography. These analyses enabled identification of specific polypeptide cleavage sites and characterization of associated N-glycans. Production of recombinant IFN-gamma in the mammalian expression systems yielded polypeptides C-terminally truncated at dibasic amino acid sites. Mammalian cell derived IFN-gamma molecules displayed oligosaccharides with monosaccharide compositions equivalent to complex, sialylated, or high-mannose type N-glycans. In contrast, IFN-gamma derived from baculovirus-infected Sf9 insect cells was truncated further toward the C-terminus and was associated with neutral (nonsialylated) N-glycans. These data demonstrate the profound influence of host cell type on posttranslational processing of recombinant proteins produced in eukaryotic systems.
Collapse
Affiliation(s)
- D C James
- Research School of Biosciences, University of Kent, Centerbury, United Kingdom.
| | | | | | | | | | | | | |
Collapse
|
40
|
Abstract
Electrospray ionization, a natural interface with microbore and capillary high-pressure liquid chromatography, has become the method of choice for the reliable structural characterization of protein glycosylation by mass spectrometry at the picomole level. Its advantages include inherent sensitivity in the femtomole range, compatibility with collisional activation methods that both permit the detection and monitoring of structurally specific ions and enable the induction of glycopeptide fragmentation that facilitates determination of glycoform sequence and branching. Developments in high-performance electrospray mass spectrometry include sample introduction at nanoliter flow rates, tandem magnetic sector/orthogonal time-of-flight instruments, Fourier transform instruments, and new ion optical strategies, including ion traps. Although a sensitive and important complementary technique, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry suffers from matrix-dependent deposition of excess internal energies, which produce extensive metastable fragmentation and (photo)adduct formation. These metastable fragments may be focused into a mass spectrum by employing an ion mirror (reflectron) in time-of-flight instrumentation. In favorable cases, structural information may be obtained.
Collapse
Affiliation(s)
- A L Burlingame
- Department of Pharmaceutical Chemistry and the Liver Center, University of California, San Francisco 94143-0446, USA
| |
Collapse
|
41
|
Mann M, Talbo G. Developments in matrix-assisted laser desorption/ionization peptide mass spectrometry. Curr Opin Biotechnol 1996; 7:11-9. [PMID: 8742374 DOI: 10.1016/s0958-1669(96)80089-9] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Most characteristics of matrix-assisted laser desorption/ionization (MALDI) are ideal for the analysis of biomolecules. New preparation techniques have dramatically increased mass accuracy and resolution, making MALDI a high-performance mass spectrometric technique for peptide mass analysis. Attempts to obtain amino acid sequence information by MALDI have been partially successful. The technique has been put to novel uses in protein primary structure characterization.
Collapse
Affiliation(s)
- M Mann
- Protein and Peptides, EMBL, Heidelberg, Germany
| | | |
Collapse
|
42
|
van Strien FJ, Jespersen S, van der Greef J, Jenks BG, Roubos EW. Identification of POMC processing products in single melanotrope cells by matrix-assisted laser desorption/ionization mass spectrometry. FEBS Lett 1996; 379:165-70. [PMID: 8635585 DOI: 10.1016/0014-5793(95)01503-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The use of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) in identifying proopiomelanocortin (POMC) processing products in melanotrope cells of the pituitary intermediate lobe of Xenopus laevis was explored. Mass spectra were obtained with such a high sensitivity of detection that the peptides could be identified in a single melanotrope cell. In addition to known POMC processing products of the Xenopus melanotrope cell, the presence of previously unidentified POMC-derived peptides was demonstrated. Together these POMC processing products accounted for the entire length of the POMC precursor. Furthermore, Xenopus possesses two genes for POMC and the sensitivity and accuracy of the MALDI-MS technique allowed identification of processing products of both the POMCA and POMCB gene. In addition, differences were obtained between the mass spectra of melanotrope cells from Xenopus laevis adapted to different conditions of background illumination. These results show that MALDI-MS is a valuable tool in the study of the expression of peptides in single (neuroendocrine) cells.
Collapse
Affiliation(s)
- F J van Strien
- Department of Animal Physiology, Nijmengen Institute for Neurosciences, Subfaculty of Biology, University of Nijmegen, The Netherlands
| | | | | | | | | |
Collapse
|
43
|
James DC. Analysis of recombinat glycoproteins by mass spectrometry. Cytotechnology 1996; 22:17-24. [DOI: 10.1007/bf00353920] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
44
|
Abstract
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been responsible for solving many problems in structural biology. Mass analysis is now used routinely to confirm proper expression and processing of proteins, and to locate and identify post-translational modifications. Innovative advances in instrumentation have led to higher mass resolution and mass accuracy. New sample preparation methods are likewise yielding higher sensitivity plus greater tolerance for buffer components that have in the past suppressed signals at higher concentrations. Advancements in the technique have also led to new or improved applications in many areas, including peptide sequencing and the identification of proteins by database searching with peptide masses. Instruments with lower cost, smaller size, and higher performance are making mass measurements available to an increasing number of laboratories. MALDI-MS is poised to continue to improve in performance and in its usefulness for current and new applications.
Collapse
Affiliation(s)
- J T Stults
- Protein Chemistry Department, Genentech, Inc, South San Francisco, California 94080, USA
| |
Collapse
|
45
|
Nakanishi T, Shimizu A, Okamoto N, Ingendoh A, Kanai M. Analysis of serum protein precipitated with antiserum by matrix-assisted laser desorption ionization/time-of-flight and electrospray ionization mass spectrometry as a clinical laboratory test. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 1995; 6:854-859. [PMID: 24214428 DOI: 10.1016/1044-0305(95)00326-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/1994] [Revised: 03/23/1995] [Accepted: 04/03/1995] [Indexed: 06/02/2023]
Abstract
Serum transferrin precipitated with specific antisera was analyzed by matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI/TOF-MS) and electrospray ionization-mass spectrometry (ESI-MS). When analyzed by MALDI, transferrin showed signal peaks that clearly could be separated from ions of IgG present in the immunoprecipitate. By ESI-MS, when the immunoprecipitates were loaded through a microcapillary polymeric reversed-phase column connected to the electrospray ionization probe, the mass spectra of transferrin were observed with a high signal-to-noise ratio and good resolution. By MALDI/TOF-MS, the observed molecular weight of normal transferrin was ∼ 1.2 ku smaller when analyzed in the reflectron mode than in the linear mode. The observed molecular weight of transferrin treated with sialidase was approximately the same in both modes. A comparison between the results obtained in both modes may help to estimate the number of sialic acids on the protein molecule. A transferrin isoform with a molecular weight of ∼2.2 ku less than the normal species was identified in the serum of patients with a carbohydrate-deficient glycoprotein syndrome as well as in heavy alcohol consumers.
Collapse
Affiliation(s)
- T Nakanishi
- Department of Clinical Pathology, Osaka Medical College, 2-7, Daigakumachi, 569, Takatsuki-city, Osaka, Japan
| | | | | | | | | |
Collapse
|
46
|
Cohen SL, Ferré-D'Amaré AR, Burley SK, Chait BT. Probing the solution structure of the DNA-binding protein Max by a combination of proteolysis and mass spectrometry. Protein Sci 1995; 4:1088-99. [PMID: 7549873 PMCID: PMC2143150 DOI: 10.1002/pro.5560040607] [Citation(s) in RCA: 138] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A simple biochemical method that combines enzymatic proteolysis and matrix-assisted laser desorption ionization mass spectrometry was developed to probe the solution structure of DNA-binding proteins. The method is based on inferring structural information from determinations of protection against enzymatic proteolysis, as governed by solvent accessibility and protein flexibility. This approach was applied to the study of the transcription factor Max--a member of the basic/helix-loop-helix/zipper family of DNA-binding proteins. In the absence of DNA and at low ionic strengths, Max is rapidly digested by each of six endoproteases selected for the study, results consistent with an open and flexible structure of the protein. At physiological salt levels, the rates of digestion are moderately slowed; this and the patterns of cleavage are consistent with homodimerization of the protein through a predominantly hydrophobic interface. In the presence of Max-specific DNA, the protein becomes dramatically protected against proteolysis, exhibiting up to a 100-fold reduction in cleavage rates. Over a 2-day period, both complete and partial proteolysis of the Max-DNA complex is observed. The partial proteolytic fragmentation patterns reflect a very high degree of protection in the N-terminal and helix-loop-helix regions of the protein, correlating with those expected of a stable dimer bound to DNA at its basic N-terminals. Less protection is seen at the C-terminal where a slow, sequential proteolytic cleavage occurs, correlating to the presence of a leucine zipper. The results also indicate a high affinity of Max for its target DNA that remains high even when the leucine zipper is proteolytically removed. In addition to the study of the helix-loop-helix protein Max, the present method appears well suited for a range of other structural biological applications.
Collapse
Affiliation(s)
- S L Cohen
- Laboratory for Mass Spectrometry and Gaseous Ion Chemistry, Rockefeller University, New York, New York 10021, USA
| | | | | | | |
Collapse
|
47
|
Kanda F, Yoshida S, Okumura T, Takamatsu T. Asparaginyl endopeptidase mapping of proteins with subsequent matrix-assisted laser desorption/ionization mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 1995; 9:1095-1100. [PMID: 7579626 DOI: 10.1002/rcm.1290091203] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A matrix-assisted laser desorption/ionization (MALDI) mass spectrometric mapping strategy for the identification and characterization of isolated and purified proteins is described. The method, which employs the combined usage of a new site-specific enzyme Asparaginyl endopeptidase (Asn-EP) for proteolysis, and MALDI for subsequent mass analysis, is capable of rapidly and sensitively examining the components of complex mixtures without any chromatographic or electrophoretic separation steps. Subpicomole sample quantities typically suffice to permit the confirmation of deduced primary structures and/or the identification of possible post-translational modifications. The data obtained should also prove useful for mass matching and sequence homology searching of computerised protein sequence data bases of known proteins.
Collapse
Affiliation(s)
- F Kanda
- Analytical Research Group, Shiseido Research Center, Yokohama, Japan
| | | | | | | |
Collapse
|