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González-Alemán R, Platero-Rochart D, Hernández-Castillo D, Hernández-Rodríguez EW, Caballero J, Leclerc F, Montero-Cabrera L. BitQT: a graph-based approach to the quality threshold clustering of molecular dynamics. Bioinformatics 2021; 38:73-79. [PMID: 34398215 DOI: 10.1093/bioinformatics/btab595] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 06/15/2021] [Accepted: 08/13/2021] [Indexed: 02/03/2023] Open
Abstract
MOTIVATION Classical Molecular Dynamics (MD) is a standard computational approach to model time-dependent processes at the atomic level. The inherent sparsity of increasingly huge generated trajectories demands clustering algorithms to reduce other post-simulation analysis complexity. The Quality Threshold (QT) variant is an appealing one from the vast number of available clustering methods. It guarantees that all members of a particular cluster will maintain a collective similarity established by a user-defined threshold. Unfortunately, its high computational cost for processing big data limits its application in the molecular simulation field. RESULTS In this work, we propose a methodological parallel between QT clustering and another well-known algorithm in the field of Graph Theory, the Maximum Clique Problem. Molecular trajectories are represented as graphs whose nodes designate conformations, while unweighted edges indicate mutual similarity between nodes. The use of a binary-encoded RMSD matrix coupled to the exploitation of bitwise operations to extract clusters significantly contributes to reaching a very affordable algorithm compared to the few implementations of QT for MD available in the literature. Our alternative provides results in good agreement with the exact one while strictly preserving the collective similarity of clusters. AVAILABILITY AND IMPLEMENTATION The source code and documentation of BitQT are free and publicly available on GitHub (https://github.com/LQCT/BitQT.git) and ReadTheDocs (https://bitqt.readthedocs.io/en/latest/), respectively. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Roy González-Alemán
- Departamento de Química-Física, Laboratorio de Química Computacional y Teórica (LQCT), Facultad de Química, Universidad de La Habana, La Habana 10400, Cuba.,Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Saclay, Gif-sur-Yvette F-91198, France
| | - Daniel Platero-Rochart
- Departamento de Química-Física, Laboratorio de Química Computacional y Teórica (LQCT), Facultad de Química, Universidad de La Habana, La Habana 10400, Cuba
| | | | - Erix W Hernández-Rodríguez
- Laboratorio de Bioinformática y Química Computacional, Escuela de Química y Farmacia, Facultad de Medicina, Universidad Católica del Maule, Talca 3460000, Chile
| | - Julio Caballero
- Departamento de Bioinformática, Facultad de Ingeniería, Centro de Bioinformática, Simulación y Modelado (CBSM), Universidad de Talca, Talca 3460000, Chile
| | - Fabrice Leclerc
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Saclay, Gif-sur-Yvette F-91198, France
| | - Luis Montero-Cabrera
- Departamento de Química-Física, Laboratorio de Química Computacional y Teórica (LQCT), Facultad de Química, Universidad de La Habana, La Habana 10400, Cuba
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González-Alemán R, Hernández-Castillo D, Caballero J, Montero-Cabrera LA. Quality Threshold Clustering of Molecular Dynamics: A Word of Caution. J Chem Inf Model 2019; 60:467-472. [PMID: 31532987 DOI: 10.1021/acs.jcim.9b00558] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Clustering Molecular Dynamics trajectories is a common analysis that allows grouping together similar conformations. Several algorithms have been designed and optimized to perform this routine task, and among them, Quality Threshold stands as a very attractive option. This algorithm guarantees that in retrieved clusters no pair of frames will have a similarity value greater than a specified threshold, and hence, a set of strongly correlated frames are obtained for each cluster. In this work, it is shown that various commonly used software implementations are flawed by confusing Quality Threshold with another simplistic well-known clustering algorithm published by Daura et al. (Daura, X.; van Gunsteren, W. F.; Jaun, B.; Mark, A. E.; Gademann, K.; Seebach, D. Peptide Folding: When Simulation Meets Experiment. Angew. Chemie Int. Ed. 1999, 38 (1/2), 236-240). Daura's algorithm does not impose any quality threshold for the frames contained in retrieved clusters, bringing unrelated structural configurations altogether. The advantages of using Quality Threshold whenever possible to explore Molecular Dynamic trajectories is exemplified. An in-house implementation of the original Quality Threshold algorithm has been developed in order to illustrate our comments, and its code is freely available for further use by the scientific community.
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Affiliation(s)
- Roy González-Alemán
- Laboratorio de Química Computacional y Teórica, Facultad de Química , Universidad de La Habana , 10400 La Habana , Cuba
| | - David Hernández-Castillo
- Laboratorio de Química Computacional y Teórica, Facultad de Química , Universidad de La Habana , 10400 La Habana , Cuba
| | - Julio Caballero
- Centro de Bioinformática y Simulación Molecular, Facultad de Ingeniería en Bioinformática , Universidad de Talca , 2 Norte 685, Casilla 721 , Talca , Chile
| | - Luis A Montero-Cabrera
- Laboratorio de Química Computacional y Teórica, Facultad de Química , Universidad de La Habana , 10400 La Habana , Cuba
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Gale PJ, Cologna SM. Alfred L. Yergey III (September 17, 1941-May 27, 2018). JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:557-560. [PMID: 30644054 DOI: 10.1007/s13361-018-2097-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- P Jane Gale
- ASMS Archivist/Historian, Southborough, MA, USA.
| | - Stephanie M Cologna
- Assistant Professor, Department of Chemistry, University of Illinois at Chicago, Chicago, IL, USA
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Tobias F, Olson MT, Cologna SM. Mass spectrometry imaging of lipids: untargeted consensus spectra reveal spatial distributions in Niemann-Pick disease type C1. J Lipid Res 2018; 59:2446-2455. [PMID: 30266834 DOI: 10.1194/jlr.d086090] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Revised: 09/24/2018] [Indexed: 12/12/2022] Open
Abstract
Mass spectrometry imaging (MSI) is a tool to rapidly map the spatial location of analytes without the need for tagging or a reporter system. Niemann-Pick disease type C1 (NPC1) is a neurodegenerative, lysosomal storage disorder characterized by accumulation of unesterified cholesterol and sphingolipids in the endo-lysosomal system. Here, we use MSI to visualize lipids including cholesterol in cerebellar brain tissue from the NPC1 symptomatic mouse model and unaffected controls. To complement the imaging studies, a data-processing pipeline was developed to generate consensus mass spectra, thereby using both technical and biological image replicates to assess differences. The consensus spectra are used to determine true differences in lipid relative abundance; lipid distributions can be determined in an unbiased fashion without prior knowledge of location. We show the cerebellar distribution of gangliosides GM1, GM2, and GM3, including variants of lipid chain length. We also performed MALDI-MSI of cholesterol. Further analysis of lobules IV/V and X of the cerebellum gangliosides indicates regional differences. The specificity achieved highlights the power of MSI, and this new workflow demonstrates a universal approach for addressing reproducibility in imaging experiments applied to NPC1.
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Affiliation(s)
- Fernando Tobias
- Department of Chemistry University of Illinois at Chicago, Chicago, IL 60607
| | - Matthew T Olson
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Jacksonville, FL 32224
| | - Stephanie M Cologna
- Department of Chemistry University of Illinois at Chicago, Chicago, IL 60607 .,Laboratory of Integrative Neuroscience, University of Illinois at Chicago, Chicago, IL 60607
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O'Rourke MB, Djordjevic SP, Padula MP. The quest for improved reproducibility in MALDI mass spectrometry. MASS SPECTROMETRY REVIEWS 2018; 37:217-228. [PMID: 27420733 DOI: 10.1002/mas.21515] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 05/19/2016] [Accepted: 06/16/2016] [Indexed: 05/18/2023]
Abstract
Reproducibility has been one of the biggest hurdles faced when attempting to develop quantitative protocols for MALDI mass spectrometry. The heterogeneous nature of sample recrystallization has made automated sample acquisition somewhat "hit and miss" with manual intervention needed to ensure that all sample spots have been analyzed. In this review, we explore the last 30 years of literature and anecdotal evidence that has attempted to address and improve reproducibility in MALDI MS. Though many methods have been attempted, we have discovered a significant publication history surrounding the use of nitrocellulose as a substrate to improve homogeneity of crystal formation and therefore reproducibility. We therefore propose that this is the most promising avenue of research for developing a comprehensive and universal preparation protocol for quantitative MALDI MS analysis. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 37:217-228, 2018.
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Affiliation(s)
- Matthew B O'Rourke
- Proteomics Core Facility, University of Technology Sydney, Cnr Harris and Thomas St, Ultimo, New South Wales, 2007, Australia
| | - Steven P Djordjevic
- The iThree Institute, University of Technology Sydney, Cnr Harris and Thomas St, Ultimo, New South Wales, 2007, Australia
| | - Matthew P Padula
- Proteomics Core Facility, University of Technology Sydney, Cnr Harris and Thomas St, Ultimo, New South Wales, 2007, Australia
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Cho YT, Su H, Wu WJ, Wu DC, Hou MF, Kuo CH, Shiea J. Biomarker Characterization by MALDI-TOF/MS. Adv Clin Chem 2015; 69:209-54. [PMID: 25934363 DOI: 10.1016/bs.acc.2015.01.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mass spectrometric techniques frequently used in clinical diagnosis, such as gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, ambient ionization mass spectrometry, and matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF/MS), are discussed. Due to its ability to rapidly detect large biomolecules in trace amounts, MALDI-TOF/MS is an ideal tool for characterizing disease biomarkers in biologic samples. Clinical applications of MS for the identification and characterization of microorganisms, DNA fragments, tissues, and biofluids are introduced. Approaches for using MALDI-TOF/MS to detect various disease biomarkers including peptides, proteins, and lipids in biological fluids are further discussed. Finally, various sample pretreatment methods which improve the detection efficiency of disease biomarkers are introduced.
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Affiliation(s)
- Yi-Tzu Cho
- Department of Cosmetic Applications and Management, Yuh-Ing Junior College of Health Care & Management, Kaohsiung, Taiwan
| | - Hung Su
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Wen-Jeng Wu
- Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Deng-Chyang Wu
- Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan; Center for Stem Cell Research, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Ming-Feng Hou
- Department of Surgery, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan; Cancer Center, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Chao-Hung Kuo
- Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan; Center for Stem Cell Research, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Jentaie Shiea
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung, Taiwan; Center for Stem Cell Research, Kaohsiung Medical University, Kaohsiung, Taiwan; Cancer Center, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan; Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung, Taiwan.
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Olson MT, Harrington C, Beierl K, Chen G, Thiess M, O’Neill A, Taube JM, Zeiger MA, Lin MT, Eshleman JR. BRAF pyrosequencing analysis aided by a lookup table. Am J Clin Pathol 2014; 141:639-47. [PMID: 24713734 DOI: 10.1309/ajcpvwh1k2zihhtv] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
OBJECTIVES BRAF mutations have substantial therapeutic, diagnostic, and prognostic significance, so detecting and specifying them is an important part of the workload of molecular pathology laboratories. Pyrosequencing assays are well suited for this analysis but can produce complex results. Therefore, we introduce a pyrosequencing lookup table based on Pyromaker that assists the user in generating hypotheses for solving complex pyrosequencing results. METHODS The lookup table contains all known mutations in the sequenced region and the positions in the dispensation sequence at which changes would occur with those mutations. We demonstrate the lookup table using a homebrew dispensation sequence for BRAF codons 596 to 605 as well as a commercially available kit-based dispensation sequence for codons 599 to 600. RESULTS These results demonstrate that the homebrew dispensation sequence unambiguously identifies all known BRAF mutations in this region, whereas the kit-based dispensation sequence has one unresolvable degeneracy that could be solved with the addition of two injections. CONCLUSIONS Using the lookup table and confirmatory virtual pyrogram, we unambiguously solved clinical pyrograms of the complex mutations V600K (c.1798_1799delGTinsAA), V600R (c.1798_1799delGTinsAG), V600D (c.1799_1800delTGinsAT), V600E (c.1799_1800delTGinsAA), and V600_K601delinsE (c.1799_1801delTGA). In addition, we used the approach to hypothesize and confirm a new mutation in human melanoma, V600_K601delinsEI (c.1799_1802delTGAAinsAAAT).
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Affiliation(s)
- Matthew T. Olson
- Departments of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Colleen Harrington
- Departments of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Katie Beierl
- Departments of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Guoli Chen
- Departments of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Michele Thiess
- Departments of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Alan O’Neill
- Departments of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Janis M. Taube
- Dermatology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Martha A. Zeiger
- Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Ming-Tseh Lin
- Departments of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - James R. Eshleman
- Departments of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD
- Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD
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Mischak H, Vlahou A, Ioannidis JP. Technical aspects and inter-laboratory variability in native peptide profiling: The CE–MS experience. Clin Biochem 2013; 46:432-43. [DOI: 10.1016/j.clinbiochem.2012.09.025] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 09/18/2012] [Accepted: 09/27/2012] [Indexed: 02/08/2023]
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Crutchfield CA, Olson MT, Gourgari E, Nesterova M, Stratakis CA, Yergey AL. Comprehensive analysis of LC/MS data using pseudocolor plots. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2013; 24:230-237. [PMID: 23283727 PMCID: PMC4141469 DOI: 10.1007/s13361-012-0524-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 10/15/2012] [Accepted: 10/23/2012] [Indexed: 06/01/2023]
Abstract
We have developed new applications of the pseudocolor plot for the analysis of LC/MS data. These applications include spectral averaging, analysis of variance, differential comparison of spectra, and qualitative filtering by compound class. These applications have been motivated by the need to better understand LC/MS data generated from analysis of human biofluids. The examples presented use data generated to profile steroid hormones in urine extracts from a Cushing's disease patient relative to a healthy control, but are general to any discovery-based scanning mass spectrometry technique. In addition to new visualization techniques, we introduce a new metric of variance: the relative maximum difference from the mean. We also introduce the concept of substructure-dependent analysis of steroid hormones using precursor ion scans. These new analytical techniques provide an alternative approach to traditional untargeted metabolomics workflow. We present an approach to discovery using MS that essentially eliminates alignment or preprocessing of spectra. Moreover, we demonstrate the concept that untargeted metabolomics can be achieved using low mass resolution instrumentation.
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