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Liang LH, Ma YD, Yang Y, Yu HL, Xia JM, Zhang T, Liu CC, Liu SL. A protein standard absolute quantification strategy for enhanced absolute quantification of ricin in complex matrices using in vitro synthesized mutant holoprotein as internal standard by ultra-high-performance liquid chromatography-tandem mass spectrometry. J Chromatogr A 2023; 1708:464373. [PMID: 37717454 DOI: 10.1016/j.chroma.2023.464373] [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: 07/09/2023] [Revised: 09/06/2023] [Accepted: 09/08/2023] [Indexed: 09/19/2023]
Abstract
Ricin is a highly toxic protein toxin that poses a potential bioterrorism threat due to its potency and widespread availability. However, the accurate quantification of ricin through absolute mass spectrometry (MS) using a protein standard absolute quantification (PSAQ) strategy is not widely practiced. This limitation primarily arises from the presence of interchain disulfide bonds, which hinder the production of full-length isotope-labeled ricin as an internal standard (IS) in vitro. In this study, we have developed a novel approach for the absolute quantification of ricin in complex matrices using recombinant single-chain and full-length mutant ricin as the protein IS, instead of isotope-labeled ricin, in conjunction with ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The amino acid sequence of the ricin mutant internal standard (RMIS) was designed by introducing site mutations in specific amino acids of trypsin/Glu-C enzymatic digestion marker peptides of ricin. To simplify protein expression, the A-chain and B-chain of RMIS were directly linked to replace the original interchain disulfide bonds. The RMISs were synthesized using an Escherichia coli expression system. An appropriate RMIS was selected as the protein IS based on consistent digestion efficiency, UHPLC-MS/MS behavior, antibody recognition function, lectin activity, and proper depurination activity with intact ricin. The RMIS was utilized to simultaneously quantify A- and B-chain marker peptides of ricin through UHPLC-MS/MS. This method was thoroughly validated using a milk matrix. By employing internal protein standards, this quantitative strategy overcomes the challenges posed by variations in extraction recoveries, matrix effects, and digestion efficiency encountered when working with different matrices. Consequently, calibration curves generated from milk matrix-spiked samples were utilized to accurately and precisely quantify ricin in river water and plasma samples. Moreover, the established method successfully detected intact ricin in samples obtained from the sixth Organization for the Prohibition of Chemical Weapons (OPCW) exercise on biotoxin analysis. This study presents a novel PSAQ strategy that enables the accurate quantification of ricin in complex matrices.
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Affiliation(s)
- Long-Hui Liang
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Yang-De Ma
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Yang Yang
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Hui-Lan Yu
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Jun-Mei Xia
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Tao Zhang
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Chang-Cai Liu
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China.
| | - Shi-Lei Liu
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China.
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Chen Z, de Boves Harrington P, Rearden P, Shetty V, Noyola A. A quantitative reliability metric for querying large database. Forensic Sci Int 2021; 331:111155. [PMID: 34972050 DOI: 10.1016/j.forsciint.2021.111155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 10/28/2021] [Accepted: 12/18/2021] [Indexed: 11/25/2022]
Abstract
A redesigned quantitative reliability metric based on the F-distribution (QRMf) is reported for evaluating the reliability of library search. The QRMf provides orthogonal information to the comparison metric (e.g., dot product) and yields a probabilistic result. An intralibrary search can be considered as an idealized search because the top hit, i.e., the closest matching object, will match perfectly. If the search of an unknown object yields the same hit list as the intralibrary search, it would indicate good reliability. For each object in the hit list, a QRMf compares the order of an intralibrary and interlibrary search results and calculates a variance of interlibrary similarity metrics between the records of the intralibrary search and records in the corresponding positions of the interlibrary search. This variance that measures the discordance of the intra and interlibrary search can simply be compared to the variance of the similarity metrics within the interlibrary search results. The ratio of these variances follows an F-distribution that can be used to determine if the discordance is statistically significant and generates the probability based on the cumulative distribution function. The QRMf works for both similarity and dissimilarity and can be used for any queried object and comparison metric that is searched against a database. In this work, the QRMf was used along with the dot product similarity to query the mass spectra of novel synthetic opioids measured by gas chromatography-mass spectrometry (GC/MS). An automated pipeline was devised that used a basis set correction to assist peak detection. The basis was constructed by mass spectra obtained from the blank measurement preceding the analytical run to remove interferences from column bleed and septum degradation. After peak detection, the pipeline applied multivariate curve resolution to the chromatographic peak window to remove background components from the mass spectra. The corrected mass spectra were searched against a customized library for identification. The QRMf can be used along with the similarity metric to detect misidentifications and assist in finding the correct identification when it is not the closest match.
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Affiliation(s)
- Zewei Chen
- Chemistry Laboratories, Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA
| | - Peter de Boves Harrington
- Chemistry Laboratories, Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA.
| | - Preshious Rearden
- Research and Development Department, Houston Forensic Science Center, Houston, TX 77002, USA
| | - Vivekananda Shetty
- Research and Development Department, Houston Forensic Science Center, Houston, TX 77002, USA
| | - Angelica Noyola
- Seized Drugs Section, Houston Forensic Science Center, Houston, TX 77002, USA
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Yang J, Wang C, Luo L, Li Z, Xu B, Guo L, Xie J. Highly sensitive MALDI-MS measurement of active ricin: insight from more potential deoxynucleobase-hybrid oligonucleotide substrates. Analyst 2021; 146:2955-2964. [PMID: 33949380 DOI: 10.1039/d0an02205e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Herein, we report an improved MALDI-MS method for active ricin to contribute toward countermeasures against its real threat to the public. Compared with commonly used DNA or RNA substrates, the deoxynucleobase-hybrid oligonucleotide (RNA_dA, Rd) substrate containing functional Gd[combining low line]A[combining low line]GA loop was revealed as a substrate with more potential and used for the first time in ricin measurement via MALDI-MS. The Rd sequence greatly prompted ricin to exhibit its catalytic activity as rRNA N-glycosylase in ex vitro condition, which was supported by molecular docking simulation and enzymatic parameters depicted in MALDI-MS. Furthermore, we discovered that a highly pure matrix was the most crucial parameter for enhancing the sensitivity, which addressed the major obstacle encountered in the oligo(deoxy)nucleotide measurement, i.e., the interfering alkali metal ion-adducted signals in MALDI-MS. After the optimization of pH and enzymatic reaction buffer composition in this ex vitro condition, this method can provide a wide linearity of up to three orders of magnitude, i.e., 1-5000 ng mL-1, and a high sensitivity of 1 ng mL-1 without any enrichment. Denatured and active ricin could be distinctly differentiated, and the application to practical samples from one international exercise and a soft drink proved the feasibility of this new method. We believe this MALDI-MS method can contribute to the first response to ricin occurrence events in public safety and security, as well as pave a new way for a deep understanding of ricin and other type II ribosome inactivating proteins involved toxicology.
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Affiliation(s)
- Jiewei Yang
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing, 100850, China.
| | - Chenyu Wang
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing, 100850, China. and School of Pharmacy, Minzu University, Beijing, 100081, China
| | - Li Luo
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing, 100850, China. and School of Public Health, Hebei Medical University, Shijiazhuang, Hebei Province 050017, China
| | - Zhi Li
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing, 100850, China.
| | - Bin Xu
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing, 100850, China.
| | - Lei Guo
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing, 100850, China.
| | - Jianwei Xie
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing, 100850, China.
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Chan QWT, Rogalski J, Moon KM, Foster LJ. The application of forensic proteomics to identify an unknown snake venom in a deceased toddler. Forensic Sci Int 2021; 323:110820. [PMID: 33984813 DOI: 10.1016/j.forsciint.2021.110820] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 04/23/2021] [Accepted: 04/26/2021] [Indexed: 10/21/2022]
Abstract
Proteomics is the global analysis of proteins in a sample, and its methodologies are commonly applied in life science research. Despite its wide applicability however, proteomics is rarely used as a tool in criminal investigations. Here we present a case where the technique provided key evidence in a case that involved the death of a two-year old girl. The defendant was known to keep exotic snakes, including several venomous species, which led the coroner to probe whether there could be snake venom in the blood of the deceased. One major challenge of the investigation was the overwhelming presence of several blood proteins, such as apolipoprotein and complement proteins, which hinders the detection of less abundant analytes. In a counter-acting strategy, a combination of immunodepletion and fractionation methods was used; the sample was then submitted to tandem mass spectrometry for peptide identification. Using this strategy, 15,000 peptides could be sequenced. However, the subsequent challenge was to differentiate between human and snake proteins, given the genetic similarities that are shared by the two vertebrate species. After a thorough bioinformatics search and manual inspection, we found that<1% of the sequenced peptides could be matched unequivocally to snake proteins, including a well-known venom component, phospholipase A2. This evidence, in part, led to a court-issued search warrant of the defendant's home, followed by his arrest and an eventual guilty plea with formal sentencing to 18 months in prison. The work outlined here is an example of how proteomics technology can help to expand the toolkit for molecular forensics.
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Affiliation(s)
- Queenie W T Chan
- Michael Smith Laboratories and Department of Biochemistry & Molecular Biology, University of British Columbia, 2185 E Mall, Vancouver, BC V6T 1Z4, Canada
| | - Jason Rogalski
- Michael Smith Laboratories and Department of Biochemistry & Molecular Biology, University of British Columbia, 2185 E Mall, Vancouver, BC V6T 1Z4, Canada
| | - Kyung-Mee Moon
- Michael Smith Laboratories and Department of Biochemistry & Molecular Biology, University of British Columbia, 2185 E Mall, Vancouver, BC V6T 1Z4, Canada
| | - Leonard J Foster
- Michael Smith Laboratories and Department of Biochemistry & Molecular Biology, University of British Columbia, 2185 E Mall, Vancouver, BC V6T 1Z4, Canada.
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Worbs S, Kampa B, Skiba M, Hansbauer EM, Stern D, Volland H, Becher F, Simon S, Dorner MB, Dorner BG. Differentiation, Quantification and Identification of Abrin and Abrus precatorius Agglutinin. Toxins (Basel) 2021; 13:toxins13040284. [PMID: 33919561 PMCID: PMC8073929 DOI: 10.3390/toxins13040284] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 04/10/2021] [Accepted: 04/13/2021] [Indexed: 12/21/2022] Open
Abstract
Abrin, the toxic lectin from the rosary pea plant Abrus precatorius, has gained considerable interest in the recent past due to its potential malevolent use. However, reliable and easy-to-use assays for the detection and discrimination of abrin from related plant proteins such as Abrus precatorius agglutinin or the homologous toxin ricin from Ricinus communis are sparse. To address this gap, a panel of highly specific monoclonal antibodies was generated against abrin and the related Abrus precatorius agglutinin. These antibodies were used to establish two sandwich ELISAs to preferentially detect abrin or A. precatorius agglutinin (limit of detection 22 pg/mL for abrin; 35 pg/mL for A. precatorius agglutinin). Furthermore, an abrin-specific lateral flow assay was developed for rapid on-site detection (limit of detection ~1 ng/mL abrin). Assays were validated for complex food, environmental and clinical matrices illustrating broad applicability in different threat scenarios. Additionally, the antibodies turned out to be suitable for immuno-enrichment strategies in combination with mass spectrometry-based approaches for unambiguous identification. Finally, we were able to demonstrate for the first time how the developed assays can be applied to detect, identify and quantify abrin from a clinical sample derived from an attempted suicide case involving A. precatorius.
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Affiliation(s)
- Sylvia Worbs
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany; (S.W.); (B.K.); (M.S.); (E.-M.H.); (D.S.); (M.B.D.)
| | - Bettina Kampa
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany; (S.W.); (B.K.); (M.S.); (E.-M.H.); (D.S.); (M.B.D.)
| | - Martin Skiba
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany; (S.W.); (B.K.); (M.S.); (E.-M.H.); (D.S.); (M.B.D.)
| | - Eva-Maria Hansbauer
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany; (S.W.); (B.K.); (M.S.); (E.-M.H.); (D.S.); (M.B.D.)
- Département Médicaments et Technologies pour la Santé, Université Paris Saclay, CEA, INRAE, SPI, 91191 Gif-sur-Yvette, France; (H.V.); (F.B.); (S.S.)
| | - Daniel Stern
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany; (S.W.); (B.K.); (M.S.); (E.-M.H.); (D.S.); (M.B.D.)
| | - Hervé Volland
- Département Médicaments et Technologies pour la Santé, Université Paris Saclay, CEA, INRAE, SPI, 91191 Gif-sur-Yvette, France; (H.V.); (F.B.); (S.S.)
| | - François Becher
- Département Médicaments et Technologies pour la Santé, Université Paris Saclay, CEA, INRAE, SPI, 91191 Gif-sur-Yvette, France; (H.V.); (F.B.); (S.S.)
| | - Stéphanie Simon
- Département Médicaments et Technologies pour la Santé, Université Paris Saclay, CEA, INRAE, SPI, 91191 Gif-sur-Yvette, France; (H.V.); (F.B.); (S.S.)
| | - Martin B. Dorner
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany; (S.W.); (B.K.); (M.S.); (E.-M.H.); (D.S.); (M.B.D.)
| | - Brigitte G. Dorner
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany; (S.W.); (B.K.); (M.S.); (E.-M.H.); (D.S.); (M.B.D.)
- Correspondence: ; Tel.: +49-30-18754-2500
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