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Kanapeckaitė A, Burokienė N, Mažeikienė A, Cottrell GS, Widera D. Biophysics is reshaping our perception of the epigenome: from DNA-level to high-throughput studies. BIOPHYSICAL REPORTS 2021; 1:100028. [PMID: 36425454 PMCID: PMC9680810 DOI: 10.1016/j.bpr.2021.100028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 09/24/2021] [Indexed: 06/16/2023]
Abstract
Epigenetic research holds great promise to advance our understanding of biomarkers and regulatory processes in health and disease. An increasing number of new approaches, ranging from molecular to biophysical analyses, enable identifying epigenetic changes on the level of a single gene or the whole epigenome. The aim of this review is to highlight how the field is shifting from completely molecular-biology-driven solutions to multidisciplinary strategies including more reliance on biophysical analysis tools. Biophysics not only offers technical advancements in imaging or structure analysis but also helps to explore regulatory interactions. New computational methods are also being developed to meet the demand of growing data volumes and their processing. Therefore, it is important to capture these new directions in epigenetics from a biophysical perspective and discuss current challenges as well as multiple applications of biophysical methods and tools. Specifically, we gradually introduce different biophysical research methods by first considering the DNA-level information and eventually higher-order chromatin structures. Moreover, we aim to highlight that the incorporation of bioinformatics, machine learning, and artificial intelligence into biophysical analysis allows gaining new insights into complex epigenetic processes. The gained understanding has already proven useful in translational and clinical research providing better patient stratification options or new therapeutic insights. Together, this offers a better readiness to transform bench-top experiments into industrial high-throughput applications with a possibility to employ developed methods in clinical practice and diagnostics.
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Affiliation(s)
- Austė Kanapeckaitė
- Algorithm379, Laisvės g. 7, LT 12007, Vilnius, Lithuania
- Reading School of Pharmacy, Whiteknights, Reading, UK, RG6 6UB
| | - Neringa Burokienė
- Clinics of Internal Diseases, Family Medicine and Oncology, Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, M. K. Čiurlionio str. 21/27, LT-03101 Vilnius, Lithuania
| | - Asta Mažeikienė
- Department of Physiology, Biochemistry, Microbiology and Laboratory Medicine, Institute of Biomedical Sciences, Faculty of Medicine, M. K. Čiurlionio str. 21/27, LT-03101 Vilnius, Lithuania
| | | | - Darius Widera
- Reading School of Pharmacy, Whiteknights, Reading, UK, RG6 6UB
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In Vitro Cytotoxicity of Secondary Metabolites Extracted from Pseudomonas aeruginosa BS25 Strain. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2020. [DOI: 10.1007/s13369-019-04092-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ushijima H, Maekawa R, Igarashi E, Akashi S. Rapid and Definitive Analysis of In Vitro DNA Methylation by Nano-electrospray Ionization Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:2335-2346. [PMID: 31529403 PMCID: PMC6828984 DOI: 10.1007/s13361-019-02304-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/25/2019] [Accepted: 07/25/2019] [Indexed: 06/10/2023]
Abstract
CpG methylation of DNA is an epigenetic marker that is highly related to the regulation of transcription initiation. For analysis of CpG methylation in genomic DNA sequences, bisulfite-induced modification in combination with polymerase chain reaction (PCR) is usually utilized, but it cannot be straightforwardly applied to methylated short- and middle-sized DNAs, such as < 500 base pairs (bp), which are often utilized in structural biology studies. In the present study, we applied nano-electrospray ionization mass spectrometry (nano-ESI-MS) for the characterization of methylated DNA with < 400 bp prepared in vitro. First, double-stranded DNA oligomers were methylated with recombinant M.SssI DNA methylase, which has been reported to modify completely and exclusively CpG sites in the sequence. The fragments generated by the digestion with methylation-insensitive restriction nuclease were then analyzed to identify the methylation levels by nano-ESI-MS, without liquid chromatography (LC) separation. By methylation-insensitive nuclease digestion, we divided the DNA strands into several fragments, and nano-ESI-MS enabled the accurate analysis of methylation levels in the DNA fragments with a relatively small amount of DNA sample prepared under optimized conditions. Furthermore, it was revealed that M.SssI methylase hardly modifies the CpG sites closely positioned at the ends of linear DNA. The present method is similar to the strategy for post-translational modification analysis of proteins and is promising for the rapid and definitive characterization of methylated DNA that may be used in structural biology studies.
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Affiliation(s)
- Hiroshi Ushijima
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Rena Maekawa
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Eri Igarashi
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Satoko Akashi
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan.
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Orr A, Stotesbury T, Wilson P, Stock NL. The use of high-resolution mass spectrometry (HRMS) for the analysis of DNA and other macromolecules: A how-to guide for forensic chemistry. Forensic Chem 2019. [DOI: 10.1016/j.forc.2019.100169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Kim SH, Hong SP, Cho W, Kim J, Lee TG, Yoon S. Rapid Genotyping of Human Papillomavirus by Desorption Electrospray Ionization Mass Spectrometry. B KOREAN CHEM SOC 2017. [DOI: 10.1002/bkcs.11130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Shin Hye Kim
- Center for Nano-Bio Measurement; Korea Research Institute of Standards and Science (KRISS); Daejeon 34113 Republic of Korea
- Department of Chemistry; Chungnam National University; Daejeon 34134 Republic of Korea
| | - Sun Pyo Hong
- R&D Center; GeneMatrix Inc; Seongnam 13543 Republic of Korea
| | - Woojae Cho
- R&D Center; GeneMatrix Inc; Seongnam 13543 Republic of Korea
| | - Jeongkwon Kim
- Department of Chemistry; Chungnam National University; Daejeon 34134 Republic of Korea
| | - Tae Geol Lee
- Center for Nano-Bio Measurement; Korea Research Institute of Standards and Science (KRISS); Daejeon 34113 Republic of Korea
| | - Sohee Yoon
- Center for Nano-Bio Measurement; Korea Research Institute of Standards and Science (KRISS); Daejeon 34113 Republic of Korea
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Miyaguchi H. Improved Polymerase Chain Reaction-restriction Fragment Length Polymorphism Genotyping of Toxic Pufferfish by Liquid Chromatography/Mass Spectrometry. J Vis Exp 2016:54402. [PMID: 27684516 PMCID: PMC5092034 DOI: 10.3791/54402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
An improved version of a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method for genotyping toxic pufferfish species by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) is described. DNA extraction is carried out using a silica membrane-based DNA extraction kit. After the PCR amplification using a detergent-free PCR buffer, restriction enzymes are added to the solution without purifying the reaction solution. A reverse-phase silica monolith column and a Fourier transform high resolution mass spectrometer having a modified Kingdon trap analyzer are employed for separation and detection, respectively. The mobile phase, consisting of 400 mM 1,1,1,3,3,3-hexafluoro-2-propanol, 15 mM triethylamine (pH 7.9) and methanol, is delivered at a flow rate of 0.4 ml/min. The cycle time for LC/ESI-MS analysis is 8 min including equilibration of the column. Deconvolution software having an isotope distribution model of the oligonucleotide is used to calculate the corresponding monoisotopic mass from the mass spectrum. For analysis of oligonucleotides (range 26-79 nucleotides), mass accuracy was 0.62 ± 0.74 ppm (n = 280) and excellent accuracy and precision were sustained for 180 hr without use of a lock mass standard.
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Miyaguchi H, Yamamuro T, Ohta H, Nakahara H, Suzuki S. Genotyping of Toxic Pufferfish Based on Specific PCR-RFLP Products As Determined by Liquid Chromatography/Quadrupole-Orbitrap Hybrid Mass Spectrometry. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:9363-9371. [PMID: 26429637 DOI: 10.1021/acs.jafc.5b03703] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A method based on liquid chromatography-electrospray mass spectrometric analysis of the enzymatically digested amplicons derived from the mitochondrial 16S rRNA gene was established for the discrimination of toxic pufferfish. A MonoBis C18 narrow-bore silica monolith column (Kyoto Monotech) and a Q Exactive mass spectrometer (Thermo Fisher) were employed for separation and detection, respectively. Monoisotopic masses of the oligonucleotides were calculated using Protein Deconvolution 3.0 software (Thermo Fisher). Although a lock mass standard was not used, excellent accuracy (mass error, 0.83 ppm on average) and precision (relative standard deviation, 0.49 ppm on average) were achieved, and a mass accuracy of <2.8 ppm was maintained for at least 180 h without additional calibration. The present method was applied to 29 pufferfish samples, and results were consistent with Sanger sequencing.
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Affiliation(s)
- Hajime Miyaguchi
- National Research Institute of Police Science , 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882, Japan
| | - Tadashi Yamamuro
- National Research Institute of Police Science , 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882, Japan
| | - Hikoto Ohta
- National Research Institute of Police Science , 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882, Japan
| | - Hiroaki Nakahara
- National Research Institute of Police Science , 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882, Japan
| | - Shinichi Suzuki
- National Research Institute of Police Science , 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882, Japan
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Manduzio H, Ezan E, Fenaille F. Evaluation of the LTQ-Orbitrap mass spectrometer for the analysis of polymerase chain reaction products. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2010; 24:3501-3509. [PMID: 21080500 DOI: 10.1002/rcm.4800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We have investigated the potential and robustness of the off-line coupling of polymerase chain reaction (PCR) with electrospray ionization mass spectrometry (ESI-MS), for further applications in the screening of single-nucleotide polymorphisms (SNPs). This was based on recently reported data demonstrating that anion-exchange solid-phase extraction was the most efficient technique for efficiently desalting PCR products, with a recovery of ∼70%. Results showed that this purification approach efficiently removes almost all the chemicals commonly added to PCR buffers. ESI-MS analysis of a model 114-bp PCR product performed on the LTQ-Orbitrap instrument demonstrated that detection limits in the nM range along with an average mass measurement uncertainty of 9.15 ± 7.11 ppm can be routinely obtained using an external calibration. The PCR/ESI-MS platform was able to detect just a few copies of a targeted oligonucleotide. However, it was shown that if two PCR products are present in a mixture in a ratio higher than 10 to 1, the lower abundance one might not be reproducibly detected. Applications to SNPs demonstrated that an LTQ-Orbitrap with a resolution of 30 000 (at m/z 400) easily identified a single (A ↔ G) switch, i.e. a 16 Da difference, in binary mixtures of ∼ 35 kDa PCR products. Complementary experiments also showed that the combination of endonucleases and ESI-MS could be used to confirm base composition and sequence, and thus to screen for unknown polymorphisms in specific sequences. For example, a single (T ↔ A) switch (9 Da mass difference) was successfully identified in a 114-bp PCR product.
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Affiliation(s)
- Hélène Manduzio
- CEA, iBiTec-S, Service de Pharmacologie et d'Immunoanalyse, 91191 Gif-sur-Yvette, France
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Manduzio H, Martelet A, Ezan E, Fenaille F. Comparison of approaches for purifying and desalting polymerase chain reaction products prior to electrospray ionization mass spectrometry. Anal Biochem 2009; 398:272-4. [PMID: 19850000 DOI: 10.1016/j.ab.2009.10.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 10/14/2009] [Accepted: 10/15/2009] [Indexed: 10/20/2022]
Abstract
We have compared the recovery and desalting efficiency of different methods (ethanol precipitation, dialysis/ultrafiltration, purification with commercial kits, anion-exchange chromatography) of purifying and desalting PCR products prior to analysis by high-resolution/high mass accuracy electrospray ionization mass spectrometry (LTQ-Orbitrap). The results support the use of anion-exchange chromatography, which shows excellent desalting efficiency with almost no adducts observed, along with a recovery of approximately 70% and the ability to purify approximately 10 samples in 45 min.
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Affiliation(s)
- Hélène Manduzio
- Commissariat à l'Energie Atomique, iBiTec-S, Service de Pharmacologie et d'Immunoanalyse, Gif-sur-Yvette, France
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On the use of different mass spectrometric techniques for characterization of sequence variability in genomic DNA. Anal Bioanal Chem 2008; 391:135-49. [DOI: 10.1007/s00216-008-1929-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Revised: 01/25/2008] [Accepted: 01/31/2008] [Indexed: 10/22/2022]
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A novel method for the detection of Roundup Ready™ soya using liquid chromatography–electrospray ionisation mass spectrometry. Eur Food Res Technol 2006. [DOI: 10.1007/s00217-006-0444-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Oberacher H, Niederstätter H, Parson W. Liquid chromatography-electrospray ionization mass spectrometry for simultaneous detection of mtDNA length and nucleotide polymorphisms. Int J Legal Med 2006; 121:57-67. [PMID: 16955300 DOI: 10.1007/s00414-006-0117-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Accepted: 07/05/2006] [Indexed: 10/24/2022]
Abstract
We demonstrate the applicability of ion-pair reversed-phase high-performance liquid chromatography-electrospray ionization time-of-flight mass spectrometry (ICEMS) for the simultaneous characterization of length and nucleotide polymorphisms. Two sections within the first (HVS-I) and second (HVS-II) hypervariable segments of the mitochondrial (mt)DNA control region were selected as targets, both containing poly-cytosine (C) tracts, which display length heteroplasmy at a substantial frequency in the population. The two mtDNA sections were simultaneously amplified and analyzed by ICEMS in 90 maternally unrelated mother-offspring pairs from Austria. The findings were confirmed by direct sequencing of the polymerase chain reaction products. For the detailed characterization of present-length heteroplasmic variants, the results retrieved through ICEMS were more informative compared with those derived from direct sequencing. Hence, ICEMS represents an interesting option for successful application in forensic science.
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Affiliation(s)
- Herbert Oberacher
- Institute of Legal Medicine, Innsbruck Medical University, Müllerstrasse 44, 6020, Innsbruck, Austria
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Oberacher H, Niederstätter H, Casetta B, Parson W. Some guidelines for the analysis of genomic DNA by PCR-LC-ESI-MS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2006; 17:124-9. [PMID: 16406562 DOI: 10.1016/j.jasms.2005.09.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2005] [Revised: 09/29/2005] [Accepted: 09/29/2005] [Indexed: 05/06/2023]
Abstract
Ion-pair reversed-phase high-performance liquid chromatography online hyphenated to electrospray ionization mass spectrometry (ICEMS) represents an efficient method for the characterization of nucleic acids amplified by polymerase chain reaction (PCR). Since sample preparation is limited to PCR, the optimization of its solution conditions is of utmost importance for efficient mass spectrometric detection. The compatibility of a number of different commercially available PCR components including DNA polymerases, deoxynucleotide triphosphates, bovine serum albumin, enhancer, and ionic buffers was evaluated. These experiments revealed that higher concentration of enhancer and detergents such as Tween-20 or Nonidet P-40 impairs the mass spectrometric detection of nucleic acids and should be avoided within the PCR mixture. The optimized analytical platform was applied to the characterization of PCR products covering parts of the first hypervariable region of the noncoding mitochondrial control region. Truncated amplicons were detected attributable to the use of low quality primers. Furthermore, due to the proofreading activity of the applied polymerase system, mismatches between the primer and the target sequence located at the last or the second last base at the 3'-end of primers were corrected and detected within the corresponding amplicons.
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Affiliation(s)
- Herbert Oberacher
- Institute of Legal Medicine, Innsbruck Medical University, Innsbruck, Austria.
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Banoub JH, Newton RP, Esmans E, Ewing DF, Mackenzie G. Recent developments in mass spectrometry for the characterization of nucleosides, nucleotides, oligonucleotides, and nucleic acids. Chem Rev 2005; 105:1869-915. [PMID: 15884792 DOI: 10.1021/cr030040w] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joseph H Banoub
- Fisheries and Oceans Canada, Science Branch, Special Projects, P.O. Box 5667, St. John's NL A1C 5X1, Canada.
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Oberacher H, Parson W, Hölzl G, Oefner PJ, Huber CG. Optimized suppression of adducts in polymerase chain reaction products for semi-quantitative SNP genotyping by liquid chromatography-mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2004; 15:1897-1906. [PMID: 15589766 DOI: 10.1016/j.jasms.2004.09.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2004] [Revised: 09/03/2004] [Accepted: 09/04/2004] [Indexed: 05/24/2023]
Abstract
While electrospray ionization mass spectrometry has shown great potential for the identification of genotypes in DNA sequences amplified by polymerase chain reaction (PCR), the quantitative determination of allele frequencies remains challenging because of the presence of cationic adducts in the mass spectra which severely impairs accuracy of quantitation. We report here on the elaboration of an optimized desalting protocol for ion-pair reversed-phase high-performance liquid chromatography-electrospray ionization mass spectrometry (ICEMS) of PCR amplicons which facilitates the genotyping of single nucleotide polymorphisms (SNPs). Chromatographic purification at temperatures between 50 and 70 degrees C using monolithic reversed-phase columns and acetonitrile gradients in aqueous, 20-30 mmol/l butyldimethylammonium bicarbonate enabled the mass spectrometric analysis of nucleic acid solutions containing up to 1.7 mol/l sodium chloride. A further improvement in removal of metal cations was achieved upon the addition of 5-10 mmol/l ethylenediaminetetraacetic acid (EDTA) to the sample solution prior to liquid chromatography. ICEMS was used for the semi-quantitative genotyping of SNPs amplified from the tetraploid genome of potato cultivars. Using a quadrupole ion trap mass spectrometer, allele frequencies were determined with an accuracy of 2-9% by measuring the relative intensities of the signals corresponding to the molecular mass of each of the alleles in the deconvoluted mass spectra. ICEMS results correlated well with those obtained by pyrosequencing, single nucleotide primer extension, and conventional dideoxy sequencing.
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Affiliation(s)
- Herbert Oberacher
- Institute of Legal Medicine, Innsbruck Medical University, Innsbruck, Austria
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Nepomuceno AI, Mason CJ, Muddiman DC, Bergen HR, Zeldenrust SR. Detection of Genetic Variants of Transthyretin by Liquid Chromatography–Dual Electrospray Ionization Fourier-Transform Ion-Cyclotron-Resonance Mass Spectrometry. Clin Chem 2004; 50:1535-43. [PMID: 15205369 DOI: 10.1373/clinchem.2004.033274] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractBackground: One of the numerous proteins causing amyloidosis is transthyretin (TTR), a protein usually responsible for the transport of thyroxine and retinol-binding protein. Variants within TTR cause it to aggregate and form insoluble fibers that accumulate in tissue, leading to organ dysfunction.Methods: TTR was immunoprecipitated from serum by use of a polyclonal antibody and subsequently reduced with tris(2-carboxyethyl)phosphine. The purified TTR was then analyzed by fast-gradient liquid chromatography–dual-electrospray ionization Fourier-transform ion-cyclotron-resonance (FT-ICR) mass spectrometry. DNA sequencing was performed on all samples used in this study.Results: Because of the inherent limitations in achieving high mass measurement accuracy based on the most abundant isotopic mass, we applied a fitting procedure that allowed determination of monoisotopic mass. Wild-type TTR (mean molecular mass, 13 761 Da) and its associated variant forms could be distinguished because of the high molecular mass accuracy afforded by FT-ICR (≤3 ppm) except for instances involving isobaric species or when isotopic distributions overlapped significantly. The [M + 11 H+]11+ charge state for all samples was used to determine the mass accuracies for both wild-type and variant forms of the protein. We correctly assigned seven of seven TTR variants. Moreover, using a combination of proteomic and genomic technologies, we discovered and characterized a previously unreported cis double mutation with a mass only 2 Da different from wild-type TTR. Furthermore, DNA sequencing of the TTR gene for all individuals in this study completely agreed with the intact protein measurements.Conclusions: FT-ICR mass spectrometry has sufficient mass accuracy to identify genetic variants of immunoaffinity-purified TTR. We believe that 91% of known TTR variants could be detected by this technique.
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Affiliation(s)
- Angelito I Nepomuceno
- WM Keck FT-ICR Mass Spectrometry Laboratory, Mayo Proteomics Research Center, Rochester, MN, USA
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Jiang Y, Hofstadler SA. A highly efficient and automated method of purifying and desalting PCR products for analysis by electrospray ionization mass spectrometry. Anal Biochem 2003; 316:50-7. [PMID: 12694726 DOI: 10.1016/s0003-2697(03)00024-1] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this work we present a rapid and fully automated method to purify and desalt PCR products prior to analysis by electrospray ionization mass spectrometry. The protocol employs a commercial pipette tip packed with an anion-exchange resin and comprises four primary steps: tip pretreatment, sample loading, rinsing, and sample elution. This tip-based purification/desalting protocol has two distinct advantages over previously published methods. First, the protocol can be performed either manually (1-12 samples at a time), using a standard p10 manual pipette, or in a fully automated microtiter plate format (96 samples at a time) employing standard laboratory robotics. Additionally, the entire protocol from crude PCR product to an "electrosprayable" analyte solution requires only 10 microl of crude product and takes less than 20 min. Using capillary gel electrophoresis, we demonstrate an overall recovery efficiency of approximately 80% and demonstrate the exquisite desalting efficiency with high-performance electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. Using an internal mass standard we demonstrate sub-ppm mass measurement error which provides an unambiguous base composition for a 120-mer PCR product.
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Affiliation(s)
- Yun Jiang
- Ibis Therapeutics, A Division of Isis Pharmaceuticals, 2292 Faraday Avenue, Carlsbad, CA 92008, USA
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Null AP, Benson LM, Muddiman DC. Enzymatic strategies for the characterization of nucleic acids by electrospray ionization mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2003; 17:2699-2706. [PMID: 14673816 DOI: 10.1002/rcm.1255] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Electrospray ionization mass spectrometry (ESI-MS) is a powerful technique used for the identification and characterization of DNA polymorphisms. Continual improvement in instrument design assures high mass measurement accuracy, sensitivity, and resolving power. This work describes an eclectic array of enzymatic strategies we have invoked in order to detect single-nucleotide polymorphisms by ESI-MS, although other applications may be envisioned. One strategy combines the use of two enzymes, exonuclease III and lambda exonuclease, to provide a ladder of single-stranded DNA fragments for straightforward sequence identification by mass spectrometry. A second strategy combines restriction enzymes to screen for polymorphisms present within specific amplicons. Finally, we describe the use of stable-isotope-labeled nucleotides for the determination of length and base composition of a PCR product.
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Affiliation(s)
- Allison P Null
- W. M. Keck FT-ICR Mass Spectrometry Laboratory, Mayo Proteomics Research Center, and Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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