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Messana I, Manconi B, Cabras T, Boroumand M, Sanna MT, Iavarone F, Olianas A, Desiderio C, Rossetti DV, Vincenzoni F, Contini C, Guadalupi G, Fiorita A, Faa G, Castagnola M. The Post-Translational Modifications of Human Salivary Peptides and Proteins Evidenced by Top-Down Platforms. Int J Mol Sci 2023; 24:12776. [PMID: 37628956 PMCID: PMC10454625 DOI: 10.3390/ijms241612776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 08/05/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023] Open
Abstract
In this review, we extensively describe the main post-translational modifications that give rise to the multiple proteoforms characterized to date in the human salivary proteome and their potential role. Most of the data reported were obtained by our group in over twenty-five years of research carried out on human saliva mainly by applying a top-down strategy. In the beginning, we describe the products generated by proteolytic cleavages, which can occur before and after secretion. In this section, the most relevant families of salivary proteins are also described. Next, we report the current information concerning the human salivary phospho-proteome and the limited news available on sulfo-proteomes. Three sections are dedicated to the description of glycation and enzymatic glycosylation. Citrullination and N- and C-terminal post-translational modifications (PTMs) and miscellaneous other modifications are described in the last two sections. Results highlighting the variation in the level of some proteoforms in local or systemic pathologies are also reviewed throughout the sections of the manuscript to underline the impact and relevance of this information for the development of new diagnostic biomarkers useful in clinical practice.
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Affiliation(s)
- Irene Messana
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”, Consiglio Nazionale delle Ricerche, 00168 Rome, Italy; (I.M.); (C.D.); (D.V.R.)
| | - Barbara Manconi
- Department of Life and Environmental Sciences, University of Cagliari, 09124 Cagliari, Italy; (B.M.); (M.T.S.); (A.O.); (C.C.); (G.G.)
| | - Tiziana Cabras
- Department of Life and Environmental Sciences, University of Cagliari, 09124 Cagliari, Italy; (B.M.); (M.T.S.); (A.O.); (C.C.); (G.G.)
| | | | - Maria Teresa Sanna
- Department of Life and Environmental Sciences, University of Cagliari, 09124 Cagliari, Italy; (B.M.); (M.T.S.); (A.O.); (C.C.); (G.G.)
| | - Federica Iavarone
- Dipartimento di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Università Cattolica del Sacro Cuore, 00168 Rome, Italy; (F.I.); (F.V.)
- Fondazione Policlinico Universitario A. Gemelli Fondazione IRCCS, 00168 Rome, Italy;
| | - Alessandra Olianas
- Department of Life and Environmental Sciences, University of Cagliari, 09124 Cagliari, Italy; (B.M.); (M.T.S.); (A.O.); (C.C.); (G.G.)
| | - Claudia Desiderio
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”, Consiglio Nazionale delle Ricerche, 00168 Rome, Italy; (I.M.); (C.D.); (D.V.R.)
| | - Diana Valeria Rossetti
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”, Consiglio Nazionale delle Ricerche, 00168 Rome, Italy; (I.M.); (C.D.); (D.V.R.)
| | - Federica Vincenzoni
- Dipartimento di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Università Cattolica del Sacro Cuore, 00168 Rome, Italy; (F.I.); (F.V.)
- Fondazione Policlinico Universitario A. Gemelli Fondazione IRCCS, 00168 Rome, Italy;
| | - Cristina Contini
- Department of Life and Environmental Sciences, University of Cagliari, 09124 Cagliari, Italy; (B.M.); (M.T.S.); (A.O.); (C.C.); (G.G.)
| | - Giulia Guadalupi
- Department of Life and Environmental Sciences, University of Cagliari, 09124 Cagliari, Italy; (B.M.); (M.T.S.); (A.O.); (C.C.); (G.G.)
| | - Antonella Fiorita
- Fondazione Policlinico Universitario A. Gemelli Fondazione IRCCS, 00168 Rome, Italy;
- Dipartimento di Scienze dell’Invecchiamento, Neurologiche, Ortopediche e della Testa e del Collo, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Gavino Faa
- Unit of Pathology, Department of Medical Sciences and Public Health, University of Cagliari, 09124 Cagliari, Italy;
- Department of Biology, College of Science and Technology, Temple University, Philadelphia, PA 19122, USA
| | - Massimo Castagnola
- Proteomics Laboratory, European Center for Brain Research, (IRCCS) Santa Lucia Foundation, 00168 Rome, Italy;
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Pieroni L, Iavarone F, Olianas A, Greco V, Desiderio C, Martelli C, Manconi B, Sanna MT, Messana I, Castagnola M, Cabras T. Enrichments of post-translational modifications in proteomic studies. J Sep Sci 2019; 43:313-336. [PMID: 31631532 DOI: 10.1002/jssc.201900804] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 09/23/2019] [Accepted: 10/17/2019] [Indexed: 12/14/2022]
Abstract
More than 300 different protein post-translational modifications are currently known, but only a few have been extensively investigated because modified proteoforms are commonly present in sub-stoichiometry amount. For this reason, improvement of specific enrichment techniques is particularly useful for the proteomic characterization of post-translationally modified proteins. Enrichment proteomic strategies could help the researcher in the challenging issue to decipher the complex molecular cross-talk existing between the different factors influencing the cellular pathways. In this review the state of art of the platforms applied for the enrichment of specific and most common post-translational modifications, such as glycosylation and glycation, phosphorylation, sulfation, redox modifications (i.e. sulfydration and nitrosylation), methylation, acetylation, and ubiquitinylation, are described. Enrichments strategies applied to characterize less studied post-translational modifications are also briefly discussed.
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Affiliation(s)
- Luisa Pieroni
- Laboratorio di Proteomica e Metabolomica, Centro Europeo di Ricerca sul Cervello, IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Federica Iavarone
- Istituto di Biochimica e Biochimica Clinica, Facoltà di Medicina, Università Cattolica del Sacro Cuore, Rome, Italy.,IRCCS Fondazione Policlinico Universitario Agostino Gemelli, Rome, Italy
| | - Alessandra Olianas
- Dipartimento di Scienze della Vita e dell'Ambiente, Università di Cagliari, Cagliari, Italy
| | - Viviana Greco
- Istituto di Biochimica e Biochimica Clinica, Facoltà di Medicina, Università Cattolica del Sacro Cuore, Rome, Italy.,IRCCS Fondazione Policlinico Universitario Agostino Gemelli, Rome, Italy
| | - Claudia Desiderio
- Istituto di Chimica del Riconoscimento Molecolare, Consiglio Nazionale delle Ricerche, Rome, Italy
| | - Claudia Martelli
- Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, Zurich, Switzerland
| | - Barbara Manconi
- Dipartimento di Scienze della Vita e dell'Ambiente, Università di Cagliari, Cagliari, Italy
| | - Maria Teresa Sanna
- Dipartimento di Scienze della Vita e dell'Ambiente, Università di Cagliari, Cagliari, Italy
| | - Irene Messana
- Istituto di Chimica del Riconoscimento Molecolare, Consiglio Nazionale delle Ricerche, Rome, Italy
| | - Massimo Castagnola
- Laboratorio di Proteomica e Metabolomica, Centro Europeo di Ricerca sul Cervello, IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Tiziana Cabras
- Dipartimento di Scienze della Vita e dell'Ambiente, Università di Cagliari, Cagliari, Italy
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Camperi J, Pichon V, Delaunay N. Separation methods hyphenated to mass spectrometry for the characterization of the protein glycosylation at the intact level. J Pharm Biomed Anal 2019; 178:112921. [PMID: 31671335 DOI: 10.1016/j.jpba.2019.112921] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 10/07/2019] [Accepted: 10/09/2019] [Indexed: 01/26/2023]
Abstract
Glycosylation is one of the most common post-translational modifications of proteins that affects their biological activity, solubility, and half-life. Therefore, its characterization is of great interest in proteomic, particularly from a diagnostic and therapeutic point of view. However, the number and type of glycosylation sites, the degree of site occupancy and the different possible structures of glycans can lead to a very large number of isoforms for a given protein, called glycoforms. The identification of these glycoforms constitutes an important analytical challenge. Indeed, to attempt to characterize all of them, it is necessary to develop efficient separation methods associated with a sensitive and informative detection mode, such as mass spectrometry (MS). Most analytical methods are based on bottom-up proteomics, which consists in the analysis of the protein at the glycopeptides level after its digestion. Even if this approach provides essential information, including the localization and composition of glycans on the protein, it is also characterized by a loss of information on macro-heterogeneity, i.e. the nature of the glycans present on a given glycoform. The analysis of glycoforms at the intact level can overcome this disadvantage. The aim of this review is to detail the state-of-the art of separation methods that can be easily hyphenated with MS for the characterization of protein glycosylation at the intact level. The different electrophoretic and chromatographic approaches are discussed in detail. The miniaturization of these separation methods is also discussed with their potential applications. While the first studies focused on the development and optimization of the separation step to achieve high resolution between isoforms, the recent ones are much more application-oriented, such as clinical diagnosis, quality control, and glycoprotein monitoring in formulations or biological samples.
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Affiliation(s)
- Julien Camperi
- Laboratory of Analytical, Bioanalytical Sciences and Miniaturization, UMR CBI 8231 CNRS - ESPCI Paris, PSL University, Paris, France
| | - Valerie Pichon
- Laboratory of Analytical, Bioanalytical Sciences and Miniaturization, UMR CBI 8231 CNRS - ESPCI Paris, PSL University, Paris, France; Sorbonne Université, Paris, France
| | - Nathalie Delaunay
- Laboratory of Analytical, Bioanalytical Sciences and Miniaturization, UMR CBI 8231 CNRS - ESPCI Paris, PSL University, Paris, France.
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Padiglia A, Orrù R, Boroumand M, Olianas A, Manconi B, Sanna MT, Desiderio C, Iavarone F, Liori B, Messana I, Castagnola M, Cabras T. Extensive Characterization of the Human Salivary Basic Proline-Rich Protein Family by Top-Down Mass Spectrometry. J Proteome Res 2018; 17:3292-3307. [PMID: 30064219 DOI: 10.1021/acs.jproteome.8b00444] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Human basic proline-rich proteins and basic glycosylated proline-rich proteins, encoded by the polymorphic PRB1-4 genes and expressed only in parotid glands, are the most complex family of adult salivary proteins. The family includes 11 parent peptides/proteins and more than 6 parent glycosylated proteins, but a high number of proteoforms with rather similar structures derive from polymorphisms and post-translational modifications. 55 new components of the family were characterized by top-down liquid chromatography-mass spectrometry and tandem-mass platforms, bringing the total number of proteoforms to 109. The new components comprise the three variants P-H S1 → A, P-Ko P36 → S, and P-Ko A41 → S and several of their naturally occurring proteolytic fragments. The paper represents an updated reference for the peptides included in the heterogeneous family of proteins encoded by PRB1/PRB4. MS data are available via ProteomeXchange with the identifier PXD009813.
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Affiliation(s)
- Alessandra Padiglia
- Department of Life and Environmental Sciences , University of Cagliari, Cittadella Univ. Monserrato , Monserrato 09042 , Cagliari , Italy
| | - Roberto Orrù
- Department of Life and Environmental Sciences , University of Cagliari, Cittadella Univ. Monserrato , Monserrato 09042 , Cagliari , Italy
| | - Mozhgan Boroumand
- Department of Life and Environmental Sciences , University of Cagliari, Cittadella Univ. Monserrato , Monserrato 09042 , Cagliari , Italy
| | - Alessandra Olianas
- Department of Life and Environmental Sciences , University of Cagliari, Cittadella Univ. Monserrato , Monserrato 09042 , Cagliari , Italy
| | - Barbara Manconi
- Department of Life and Environmental Sciences , University of Cagliari, Cittadella Univ. Monserrato , Monserrato 09042 , Cagliari , Italy
| | - Maria Teresa Sanna
- Department of Life and Environmental Sciences , University of Cagliari, Cittadella Univ. Monserrato , Monserrato 09042 , Cagliari , Italy
| | - Claudia Desiderio
- Institute of Chemistry of Molecular Recognition , CNR , Rome 00168 , Italy
| | - Federica Iavarone
- Institute of Biochemistry and Clinical Biochemistry , Università Cattolica del Sacro Cuore , Rome 00168 , Italy.,Department of Laboratory Diagnostic and Infectious Diseases , Fondazione Policlinico Universitario Agostino Gemelli-IRCCS , Rome 00168 , Italy
| | - Barbara Liori
- Department of Life and Environmental Sciences , University of Cagliari, Cittadella Univ. Monserrato , Monserrato 09042 , Cagliari , Italy
| | - Irene Messana
- Institute of Chemistry of Molecular Recognition , CNR , Rome 00168 , Italy
| | - Massimo Castagnola
- Institute of Chemistry of Molecular Recognition , CNR , Rome 00168 , Italy.,Institute of Biochemistry and Clinical Biochemistry , Università Cattolica del Sacro Cuore , Rome 00168 , Italy.,Department of Laboratory Diagnostic and Infectious Diseases , Fondazione Policlinico Universitario Agostino Gemelli-IRCCS , Rome 00168 , Italy
| | - Tiziana Cabras
- Department of Life and Environmental Sciences , University of Cagliari, Cittadella Univ. Monserrato , Monserrato 09042 , Cagliari , Italy
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Ekström J, Khosravani N, Castagnola M, Messana I. Saliva and the Control of Its Secretion. Dysphagia 2017. [DOI: 10.1007/174_2017_143] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Manconi B, Cabras T, Sanna M, Piras V, Liori B, Pisano E, Iavarone F, Vincenzoni F, Cordaro M, Faa G, Castagnola M, Messana I. N- and O-linked glycosylation site profiling of the human basic salivary proline-rich protein 3M. J Sep Sci 2016; 39:1987-97. [DOI: 10.1002/jssc.201501306] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 03/03/2016] [Accepted: 03/04/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Barbara Manconi
- Dipartimento di Scienze della Vita e dell'Ambiente; Università di Cagliari; Cagliari Italy
| | - Tiziana Cabras
- Dipartimento di Scienze della Vita e dell'Ambiente; Università di Cagliari; Cagliari Italy
| | - Monica Sanna
- Dipartimento di Scienze della Vita e dell'Ambiente; Università di Cagliari; Cagliari Italy
| | - Valentina Piras
- Dipartimento di Scienze della Vita e dell'Ambiente; Università di Cagliari; Cagliari Italy
| | - Barbara Liori
- Dipartimento di Scienze della Vita e dell'Ambiente; Università di Cagliari; Cagliari Italy
| | - Elisabetta Pisano
- Dipartimento di Scienze Chirurgiche; Università di Cagliari; Cagliari Italy
| | - Federica Iavarone
- Istituto di Biochimica e Biochimica Clinica; Università Cattolica; Roma Italy
| | - Federica Vincenzoni
- Istituto di Biochimica e Biochimica Clinica; Università Cattolica; Roma Italy
| | - Massimo Cordaro
- Istituto di Clinica Odontostomatologica, Facoltà di Medicina; Università Cattolica; Roma Italy
| | - Gavino Faa
- Dipartimento di Scienze Chirurgiche; Università di Cagliari; Cagliari Italy
| | - Massimo Castagnola
- Istituto di Biochimica e Biochimica Clinica; Università Cattolica; Roma Italy
- Istituto di Chimica del Riconoscimento Molecolare - CNR; Roma Italy
| | - Irene Messana
- Istituto di Chimica del Riconoscimento Molecolare - CNR; Roma Italy
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7
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Manconi B, Castagnola M, Cabras T, Olianas A, Vitali A, Desiderio C, Sanna MT, Messana I. The intriguing heterogeneity of human salivary proline-rich proteins. J Proteomics 2016; 134:47-56. [DOI: 10.1016/j.jprot.2015.09.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 09/01/2015] [Accepted: 09/07/2015] [Indexed: 01/10/2023]
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Top-down analytical platforms for the characterization of the human salivary proteome. Bioanalysis 2014; 6:563-81. [PMID: 24568357 DOI: 10.4155/bio.13.349] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Comprehensive analysis and characterization of the human salivary proteome is an important step towards the possible use of saliva for diagnostic and prognostic purposes. The contribution of the different sources to whole saliva, and the evaluation of individual variability and physiological modifications have been investigated by top-down proteomic approaches, disclosing the faceted and complex profile of the human salivary proteome. All this information is essential to develop saliva protein biomarkers. In this Review the major results obtained in the field by top-down platforms, and the improvements required to allow a more complete picture, will be discussed.
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Iavarone F, D'Alessandro A, Tian N, Cabras T, Messana I, Helmerhorst EJ, Oppenheim FG, Castagnola M. High-resolution high-performance liquid chromatography with electrospray ionization mass spectrometry and tandem mass spectrometry characterization of a new isoform of human salivary acidic proline-rich proteins named Roma-Boston Ser₂₂ (Phos) → Phe variant. J Sep Sci 2014; 37:1896-902. [PMID: 24771659 DOI: 10.1002/jssc.201400227] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 04/08/2014] [Accepted: 04/14/2014] [Indexed: 11/10/2022]
Abstract
During a survey of human saliva by a top-down reversed-phase high-performance liquid chromatography with electrospray ionization mass spectrometry approach, two proteins eluting at 27.4 and 28.4 min, with average masses of 15 494 ± 1 and 11 142 ± 1 Da, were detected in a subject from Boston. The Δmass value (4352 Da) of the two proteins was similar to the difference in mass values between intact (150 amino acids, [a.a.]) and truncated acidic proline-rich proteins (aPRPs; 106 a.a.) suggesting an a.a. substitution in the first 106 residues resulting in a strong reduction in polarity, since under the same experimental conditions aPRPs eluted at ∼22.5 min (intact) and 23.5 min (truncated forms). Manual inspection of the high-resolution high-performance liquid chromatography with electrospray ionization tandem mass spectra of the truncated isoform showed the replacement of the phosphorylated Ser-22 in PRP-3 with a Phe residue. Inspection of the tandem mass spectra of the intact isoform confirmed the substitution, which is allowed by the code transition TCT→TTT and is in agreement with the dramatic increase in elution time. The isoform was also detected in two other subjects, one from Boston (unrelated to the previous) and one from Rome. For this reason we propose to name this variant PRP-1 (PRP-3) RB (Roma-Boston) Ser22 (phos)→Phe.
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Affiliation(s)
- Federica Iavarone
- Facoltà di Medicina, Istituto di Biochimica e di Biochimica Clinica and/or Istituto per la Chimica del Riconoscimento Molecolare (CNR), Università Cattolica, Roma, Italy
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10
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Vitorino R, Ferreira R, Caseiro A, Amado F. Salivary Peptidomics Targeting Clinical Applications. COMPREHENSIVE ANALYTICAL CHEMISTRY 2014. [DOI: 10.1016/b978-0-444-62650-9.00009-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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11
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Jeong EK, Ha IJ, Kim YS, Na YC. Glycosylated platycosides: identification by enzymatic hydrolysis and structural determination by LC-MS/MS. J Sep Sci 2013; 37:61-8. [PMID: 24327461 DOI: 10.1002/jssc.201300918] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 10/24/2013] [Accepted: 10/27/2013] [Indexed: 11/05/2022]
Abstract
In this study, enzymatic hydrolysis and chemometric methods were utilized to discriminate glycosylated platycosides in the extract of Platycodi Radix by LC-MS. Laminarinase, whose enzymatic activity was evaluated using gentiobiose and laminaritriose, was a suitable enzyme to identify the glycosylated platycosides. The laminarinase produced deapi-platycodin D and platycodin D from the isolated deapi-platycoside E and platycoside E through the loss of two glucose units by enzymatic reaction, respectively. After hydrolyzing a crude extract by laminarinase, the reconstructed total ion chromatogram generated by a chemometric technique sorted peaks of deglycosylated platycosides easily. Structural information of the glycosylated isomers was revealed through fragment ions generated by the sodiated C0β ion corresponding to reduced disaccharides in the positive MS(4) spectra. Characteristic fragment ions of Glc-(1→6)-Glc moieties were observed through ring cleavages of (0,2)A0β, (0,3)A0β, and (0,4)A0β, whereas Glc-(1→3)-Glc moieties produced only (0,3)A0β ions. Lithium-adducted platycosides allowed more detailed structural analysis of glycosidic bond cleavage corresponding to Y1β and B1β in addition to ring cleavage.
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Affiliation(s)
- Eun-Kyung Jeong
- Analytical Research Division, Seoul Center, Korea Basic Science Institute, Seoul, South Korea
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Castagnola M, Cabras T, Iavarone F, Vincenzoni F, Vitali A, Pisano E, Nemolato S, Scarano E, Fiorita A, Vento G, Tirone C, Romagnoli C, Cordaro M, Paludetti G, Faa G, Messana I. Top-down platform for deciphering the human salivary proteome. J Matern Fetal Neonatal Med 2013; 25:27-43. [PMID: 23025766 DOI: 10.3109/14767058.2012.714647] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Proteomic platforms can be classified in bottom-up strategies, which analyze the sample after proteolytic digestion, and top-down strategies, which analyze the intact naturally occurring proteome. Bottom-up platforms are high-throughput because they can investigate a large number of proteins, regardless of their dimension. Nonetheless, information on post-translational modifications (PTMs) can be lost, especially those regarding naturally occurring cleavages and alternative splicing. Top-down platforms cannot cover vast proteomes, however, they can disclose subtle structural variations occurring during protein maturation and allow label-free relative quantifications in an unlimited number of samples. A repertoire of 256 masses belonging to naturally occurring proteins and peptides consistently detected by RP-HPLC-ESI-MS analysis of the acidic soluble fraction of human whole saliva is presented in this study. Of them, 233 have been identified, while 23 are still pending for the definitive characterization. The present review reports average and mono-isotopic masses of the peptides and proteins detected, RP-HPLC elution times, PTMs, origin and quali-quantitative variations observed in several physiological and pathological conditions. The information reported can be a reference for users of top-down RP-HPLC-ESI-MS proteomic platforms applied to the study of the human salivary proteome as well as of other human bodily fluids.
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Affiliation(s)
- Massimo Castagnola
- Istituto di Biochimica e Biochimica Clinica, Facoltà di Medicina, Università Cattolica, Largo Francesco Vito 1, Rome, Italy.
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