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Bender O, Khoury J, Hirsch G, Weinberg E, Sagy N, Buller S, Lapides-Levy S, Blumer S, Bar DZ. Immunorecognition of Streptococcus mutans secreted proteins protects against caries by limiting tooth adhesion. J Dent 2024; 141:104805. [PMID: 38101504 DOI: 10.1016/j.jdent.2023.104805] [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: 08/15/2023] [Revised: 12/03/2023] [Accepted: 12/12/2023] [Indexed: 12/17/2023] Open
Abstract
INTRODUCTION Childhood caries, a prevalent chronic disease, affects 60-90 % of children in industrialized regions, leading to lesions in both primary and permanent teeth. This condition precipitates hospital admissions, emergency room visits, elevated treatment costs, and missed school days, thereby impeding the child's academic engagement and increasing the likelihood of caries into adulthood. Despite multiple identified risk factors, significant interpersonal variability remains unexplained. The immune system generates a unique antibody repertoire, essential for maintaining a balanced and healthy oral microbiome. Streptococcus mutans is a primary contributor to the development of caries. METHODS Employing mass spectrometry, we investigated the S. mutans proteins targeted by antibodies in children both with and without caries, delineating a fundamental suite of proteins discernible by the immune systems of a majority of individuals. Notably, this suite was enriched with proteins pivotal for bacterial adhesion. To ascertain the physiological implications of these discoveries, we evaluated the efficacy of saliva in thwarting S. mutans adherence to dental surfaces. RESULTS Antibodies in most children recognized a core set of ten S. mutans proteins, with additional proteins identified in some individuals. There was no significant difference in the proteins identified by children with or without caries, but there was variation in antibody binding intensity to some proteins. Functionally, saliva from caries-free individuals, but not children with caries, was found to hinder the binding of S. mutans to teeth. These findings delineate the S. mutans proteome targeted by the immune system and suggest that the inhibition of bacterial adherence to teeth is a primary mechanism employed by the immune system to maintain oral balance and prevent caries formation. CONCLUSIONS These findings enhance our knowledge of the immune system's function in oral health maintenance and caries prevention, shedding light on how immunoglobulins interact with S. mutans proteins. CLINICAL SIGNIFICANCE Targeting S. mutans proteins implicated in bacterial adhesion could be a promising strategy for preventing childhood caries.
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Affiliation(s)
- Omer Bender
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Faculty of Medicine, Tel Aviv University 69978, Israel
| | - Jessica Khoury
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Faculty of Medicine, Tel Aviv University 69978, Israel
| | - Gal Hirsch
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Faculty of Medicine, Tel Aviv University 69978, Israel
| | - Evgeny Weinberg
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Faculty of Medicine, Tel Aviv University 69978, Israel; Department of Periodontology, The Goldschleger School of Dental Medicine, Faculty of Medicine, Tel Aviv University 69978, Israel
| | - Naor Sagy
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Faculty of Medicine, Tel Aviv University 69978, Israel
| | - Shani Buller
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Faculty of Medicine, Tel Aviv University 69978, Israel
| | - Shiri Lapides-Levy
- Department of Pediatric Dentistry, The Goldschleger School of Dental Medicine, Faculty of Medicine, Tel Aviv University 69978, Israel
| | - Sigalit Blumer
- Department of Pediatric Dentistry, The Goldschleger School of Dental Medicine, Faculty of Medicine, Tel Aviv University 69978, Israel
| | - Daniel Z Bar
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Faculty of Medicine, Tel Aviv University 69978, Israel.
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2
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Geens R, Stanisich J, Beyens O, D'Hondt S, Thiberge J, Ryckebosch A, De Groot A, Magez S, Vertommen D, Amino R, De Winter H, Volkov AN, Tompa P, Sterckx YG. Biophysical characterization of the Plasmodium falciparum circumsporozoite protein's N-terminal domain. Protein Sci 2024; 33:e4852. [PMID: 38059674 PMCID: PMC10749493 DOI: 10.1002/pro.4852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 11/28/2023] [Accepted: 12/04/2023] [Indexed: 12/08/2023]
Abstract
The circumsporozoite protein (CSP) is the main surface antigen of the Plasmodium sporozoite (SPZ) and forms the basis of the currently only licensed anti-malarial vaccine (RTS,S/AS01). CSP uniformly coats the SPZ and plays a pivotal role in its immunobiology, in both the insect and the vertebrate hosts. Although CSP's N-terminal domain (CSPN ) has been reported to play an important role in multiple CSP functions, a thorough biophysical and structural characterization of CSPN is currently lacking. Here, we present an alternative method for the recombinant production and purification of CSPN from Plasmodium falciparum (PfCSPN ), which provides pure, high-quality protein preparations with high yields. Through an interdisciplinary approach combining in-solution experimental methods and in silico analyses, we provide strong evidence that PfCSPN is an intrinsically disordered region displaying some degree of compaction.
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Affiliation(s)
- Rob Geens
- Laboratory of Medical Biochemistry (LMB)University of AntwerpAntwerpBelgium
- Structural Biology BrusselsVrije Universiteit BrusselBrusselsBelgium
| | - Jessica Stanisich
- Cellular and Molecular ImmunologyVrije Universiteit BrusselBrusselsBelgium
| | - Olivier Beyens
- Laboratory of Medicinal Chemistry (UAMC)University of AntwerpAntwerpBelgium
| | - Stijn D'Hondt
- Laboratory of Medicinal Chemistry (UAMC)University of AntwerpAntwerpBelgium
| | | | - Amber Ryckebosch
- Laboratory of Medical Biochemistry (LMB)University of AntwerpAntwerpBelgium
| | - Anke De Groot
- Laboratory of Medical Biochemistry (LMB)University of AntwerpAntwerpBelgium
| | - Stefan Magez
- Cellular and Molecular ImmunologyVrije Universiteit BrusselBrusselsBelgium
- Ghent University Global CampusIncheonSouth Korea
| | - Didier Vertommen
- de Duve Institute and MASSPROT Platform, UCLouvainBrusselsBelgium
| | - Rogerio Amino
- Unit of Malaria Infection & ImmunityInstitut PasteurParisFrance
| | - Hans De Winter
- Laboratory of Medicinal Chemistry (UAMC)University of AntwerpAntwerpBelgium
| | - Alexander N. Volkov
- Structural Biology BrusselsVrije Universiteit BrusselBrusselsBelgium
- VIB‐VUB Center for Structural BiologyVlaams Instituut voor Biotechnologie (VIB)BrusselsBelgium
- Jean Jeener NMR CentreVrije Universiteit BrusselBrusselsBelgium
| | - Peter Tompa
- Structural Biology BrusselsVrije Universiteit BrusselBrusselsBelgium
- VIB‐VUB Center for Structural BiologyVlaams Instituut voor Biotechnologie (VIB)BrusselsBelgium
- Institute of Enzymology, Biological Research CenterHungarian Academy of SciencesBudapestHungary
| | - Yann G.‐J. Sterckx
- Laboratory of Medical Biochemistry (LMB)University of AntwerpAntwerpBelgium
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3
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Davies H, Belda H, Broncel M, Dalimot J, Treeck M. PerTurboID, a targeted in situ method reveals the impact of kinase deletion on its local protein environment in the cytoadhesion complex of malaria-causing parasites. eLife 2023; 12:e86367. [PMID: 37737226 PMCID: PMC10564455 DOI: 10.7554/elife.86367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 09/21/2023] [Indexed: 09/23/2023] Open
Abstract
Reverse genetics is key to understanding protein function, but the mechanistic connection between a gene of interest and the observed phenotype is not always clear. Here we describe the use of proximity labeling using TurboID and site-specific quantification of biotinylated peptides to measure changes to the local protein environment of selected targets upon perturbation. We apply this technique, which we call PerTurboID, to understand how the Plasmodium falciparum-exported kinase, FIKK4.1, regulates the function of the major virulence factor of the malaria-causing parasite, PfEMP1. We generated independent TurboID fusions of two proteins that are predicted substrates of FIKK4.1 in a FIKK4.1 conditional KO parasite line. Comparing the abundance of site-specific biotinylated peptides between wildtype and kinase deletion lines reveals the differential accessibility of proteins to biotinylation, indicating changes to localization, protein-protein interactions, or protein structure which are mediated by FIKK4.1 activity. We further show that FIKK4.1 is likely the only FIKK kinase that controls surface levels of PfEMP1, but not other surface antigens, on the infected red blood cell under standard culture conditions. We believe PerTurboID is broadly applicable to study the impact of genetic or environmental perturbation on a selected cellular niche.
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Affiliation(s)
- Heledd Davies
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Hugo Belda
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Malgorzata Broncel
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Jill Dalimot
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Moritz Treeck
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
- Cell Biology of Host-Pathogen Interaction Laboratory, Gulbenkian Institute of ScienceOeirasPortugal
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4
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Martin GM, Torres JL, Pholcharee T, Oyen D, Flores-Garcia Y, Gibson G, Moskovitz R, Beutler N, Jung DD, Copps J, Lee WH, Gonzalez-Paez G, Emerling D, MacGill RS, Locke E, King CR, Zavala F, Wilson IA, Ward AB. Affinity-matured homotypic interactions induce spectrum of PfCSP structures that influence protection from malaria infection. Nat Commun 2023; 14:4546. [PMID: 37507365 PMCID: PMC10382551 DOI: 10.1038/s41467-023-40151-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 07/14/2023] [Indexed: 07/30/2023] Open
Abstract
The generation of high-quality antibody responses to Plasmodium falciparum (Pf) circumsporozoite protein (PfCSP), the primary surface antigen of Pf sporozoites, is paramount to the development of an effective malaria vaccine. Here we present an in-depth structural and functional analysis of a panel of potent antibodies encoded by the immunoglobulin heavy chain variable (IGHV) gene IGHV3-33, which is among the most prevalent and potent antibody families induced in the anti-PfCSP immune response and targets the Asn-Ala-Asn-Pro (NANP) repeat region. Cryo-electron microscopy (cryo-EM) reveals a remarkable spectrum of helical antibody-PfCSP structures stabilized by homotypic interactions between tightly packed fragments antigen binding (Fabs), many of which correlate with somatic hypermutation. We demonstrate a key role of these mutated homotypic contacts for high avidity binding to PfCSP and in protection from Pf malaria infection. Together, these data emphasize the importance of anti-homotypic affinity maturation in the frequent selection of IGHV3-33 antibodies and highlight key features underlying the potent protection of this antibody family.
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Affiliation(s)
- Gregory M Martin
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Jonathan L Torres
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Tossapol Pholcharee
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
- Department of Biochemistry, University of Oxford, Oxford, OX1 3DR, UK
| | - David Oyen
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
- Pfizer Inc, San Diego, CA, 92121, USA
| | - Yevel Flores-Garcia
- Department of Molecular Microbiology and Immunology, Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Grace Gibson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Re'em Moskovitz
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Nathan Beutler
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Diana D Jung
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Jeffrey Copps
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Wen-Hsin Lee
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Gonzalo Gonzalez-Paez
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | | | | | - Emily Locke
- PATH's Malaria Vaccine Initiative, Washington, DC, 20001, USA
| | - C Richter King
- PATH's Malaria Vaccine Initiative, Washington, DC, 20001, USA
| | - Fidel Zavala
- Department of Molecular Microbiology and Immunology, Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA.
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5
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Mohammed M, Dziedziech A, Sekar V, Ernest M, Alves E Silva TL, Balan B, Emami SN, Biryukova I, Friedländer MR, Jex A, Jacobs-Lorena M, Henriksson J, Vega-Rodriguez J, Ankarklev J. Single-Cell Transcriptomics To Define Plasmodium falciparum Stage Transition in the Mosquito Midgut. Microbiol Spectr 2023; 11:e0367122. [PMID: 36847501 PMCID: PMC10100735 DOI: 10.1128/spectrum.03671-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 02/05/2023] [Indexed: 03/01/2023] Open
Abstract
Malaria inflicts the highest rate of morbidity and mortality among the vector-borne diseases. The dramatic bottleneck of parasite numbers that occurs in the gut of the obligatory mosquito vector provides a promising target for novel control strategies. Using single-cell transcriptomics, we analyzed Plasmodium falciparum development in the mosquito gut, from unfertilized female gametes through the first 20 h after blood feeding, including the zygote and ookinete stages. This study revealed the temporal gene expression of the ApiAP2 family of transcription factors and of parasite stress genes in response to the harsh environment of the mosquito midgut. Further, employing structural protein prediction analyses, we found several upregulated genes predicted to encode intrinsically disordered proteins (IDPs), a category of proteins known for their importance in regulation of transcription, translation, and protein-protein interactions. IDPs are known for their antigenic properties and may serve as suitable targets for antibody- or peptide-based transmission suppression strategies. In total, this study uncovers the P. falciparum transcriptome from early to late parasite development in the mosquito midgut, inside its natural vector, which provides an important resource for future malaria transmission-blocking initiatives. IMPORTANCE The malaria parasite Plasmodium falciparum causes more than half a million deaths per year. The current treatment regimen targets the symptom-causing blood stage inside the human host. However, recent incentives in the field call for novel interventions to block parasite transmission from humans to the mosquito vector. Therefore, we need to better understand the parasite biology during its development inside the mosquito, including a deeper understanding of the expression of genes controlling parasite progression during these stages. Here, we have generated single-cell transcriptome data, covering P. falciparum's development, from gamete to ookinete inside the mosquito midgut, uncovering previously untapped parasite biology, including a repertoire of novel biomarkers to be explored in future transmission-blocking efforts. We anticipate that our study provides an important resource, which can be further explored to improve our understanding of the parasite biology as well as aid in guiding future malaria intervention strategies.
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Affiliation(s)
- Mubasher Mohammed
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Alexis Dziedziech
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Vaishnovi Sekar
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Medard Ernest
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Thiago Luiz Alves E Silva
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Balu Balan
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - S. Noushin Emami
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Inna Biryukova
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Marc R. Friedländer
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Aaron Jex
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Marcelo Jacobs-Lorena
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - Johan Henriksson
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Joel Vega-Rodriguez
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Johan Ankarklev
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
- Microbial Single Cell Genomics, Department of Cell and Molecular Biology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
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6
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Raghavan M, Kalantar KL, Duarte E, Teyssier N, Takahashi S, Kung AF, Rajan JV, Rek J, Tetteh KKA, Drakeley C, Ssewanyana I, Rodriguez-Barraquer I, Greenhouse B, DeRisi JL. Antibodies to repeat-containing antigens in Plasmodium falciparum are exposure-dependent and short-lived in children in natural malaria infections. eLife 2023; 12:e81401. [PMID: 36790168 PMCID: PMC10005774 DOI: 10.7554/elife.81401] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 02/14/2023] [Indexed: 02/16/2023] Open
Abstract
Protection against Plasmodium falciparum, which is primarily antibody-mediated, requires recurrent exposure to develop. The study of both naturally acquired limited immunity and vaccine induced protection against malaria remains critical for ongoing eradication efforts. Towards this goal, we deployed a customized P. falciparum PhIP-seq T7 phage display library containing 238,068 tiled 62-amino acid peptides, covering all known coding regions, including antigenic variants, to systematically profile antibody targets in 198 Ugandan children and adults from high and moderate transmission settings. Repeat elements - short amino acid sequences repeated within a protein - were significantly enriched in antibody targets. While breadth of responses to repeat-containing peptides was twofold higher in children living in the high versus moderate exposure setting, no such differences were observed for peptides without repeats, suggesting that antibody responses to repeat-containing regions may be more exposure dependent and/or less durable in children than responses to regions without repeats. Additionally, short motifs associated with seroreactivity were extensively shared among hundreds of antigens, potentially representing cross-reactive epitopes. PfEMP1 shared motifs with the greatest number of other antigens, partly driven by the diversity of PfEMP1 sequences. These data suggest that the large number of repeat elements and potential cross-reactive epitopes found within antigenic regions of P. falciparum could contribute to the inefficient nature of malaria immunity.
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Affiliation(s)
- Madhura Raghavan
- University of California, San FranciscoSan FranciscoUnited States
| | | | - Elias Duarte
- University of California, BerkeleyBerkeleyUnited States
| | - Noam Teyssier
- University of California, San FranciscoSan FranciscoUnited States
| | - Saki Takahashi
- University of California, San FranciscoSan FranciscoUnited States
| | - Andrew F Kung
- University of California, San FranciscoSan FranciscoUnited States
| | - Jayant V Rajan
- University of California, San FranciscoSan FranciscoUnited States
| | - John Rek
- Infectious Diseases Research CollaborationKampalaUganda
| | - Kevin KA Tetteh
- London School of Hygiene and Tropical MedicineLondonUnited Kingdom
| | - Chris Drakeley
- London School of Hygiene and Tropical MedicineLondonUnited Kingdom
| | - Isaac Ssewanyana
- Infectious Diseases Research CollaborationKampalaUganda
- London School of Hygiene and Tropical MedicineLondonUnited Kingdom
| | - Isabel Rodriguez-Barraquer
- University of California, San FranciscoSan FranciscoUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
| | - Bryan Greenhouse
- University of California, San FranciscoSan FranciscoUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
| | - Joseph L DeRisi
- University of California, San FranciscoSan FranciscoUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
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7
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Ramirez-Montoya MV, García-Olivares D, Acosta H, Rojas A. In silico integrative analysis for the characterization of LYT1 a unique protein of Trypanosoma cruzi. J Biomol Struct Dyn 2022; 40:13154-13160. [PMID: 34583627 DOI: 10.1080/07391102.2021.1982771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Trypanosoma rangeli is the most similar organism to Trypanosoma cruzi. They share distribution areas, hosts, and some vectors. However, there are key differences between them; the first lacks a multiplicative form in the host and does not cause disease, while the second is the etiological agent of the American tripanosomiasis, a tropical disease that still does not have an effective vaccine nor treatment. Aiming to reveal the differences in their gene expression patterns in each life cycle form, the comparison of expression profiles was made parting from the ESTs available in TriTrypDB. We verified that there are no genes unique to T. rangeli in the ESTs. Astonishingly, we determined that T. cruzi has a single copy gene called LYT1, which has no similarity to any other protein of any organism on Earth. LYT1 is involved in invasion, motility, and cell cycle, making it an attractive vaccine target. After its identification, using immunoinformatics programs, we found multiple potential B- and T-cell epitopes in this protein, which is also rich in intrinsically disordered regions. Additionally, an approximation of the 3 D structure was predicted where the B-cell epitopes were located to assess their solvent access. We propose that its particular structural conformation confers the flexibility required for the interactions with multiple proteins, which in part may be performed through N-myristoylation sites. Given its important role in the infectiveness of T. cruzi and its antigenic potential, we highlight the need for future studies focused on its molecular and immunological in vivo characterization.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- María Virginia Ramirez-Montoya
- The National Center of Scientific Calculus at the Universidad de Los Andes (CeCalCULA, Universidad de Los Andes, Mérida, Venezuela
| | - Danielle García-Olivares
- The National Center of Scientific Calculus at the Universidad de Los Andes (CeCalCULA, Universidad de Los Andes, Mérida, Venezuela
| | - Héctor Acosta
- Laboratory of Animal Physiology, Faculty of Science, Universidad de Los Andes, Mérida, Venezuela.,Laboratory of Parasite Enzimology, Faculty of Science, Universidad de Los Andes, Mérida, Venezuela
| | - Ascanio Rojas
- The National Center of Scientific Calculus at the Universidad de Los Andes (CeCalCULA, Universidad de Los Andes, Mérida, Venezuela
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8
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Deletion of the Plasmodium falciparum exported protein PTP7 leads to Maurer’s clefts vesiculation, host cell remodeling defects, and loss of surface presentation of EMP1. PLoS Pathog 2022; 18:e1009882. [PMID: 35930605 PMCID: PMC9385048 DOI: 10.1371/journal.ppat.1009882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 08/17/2022] [Accepted: 06/19/2022] [Indexed: 11/19/2022] Open
Abstract
Presentation of the variant antigen, Plasmodium falciparum erythrocyte membrane protein 1 (EMP1), at knob-like protrusions on the surface of infected red blood cells, underpins the parasite’s pathogenicity. Here we describe a protein PF3D7_0301700 (PTP7), that functions at the nexus between the intermediate trafficking organelle, the Maurer’s cleft, and the infected red blood cell surface. Genetic disruption of PTP7 leads to accumulation of vesicles at the Maurer’s clefts, grossly aberrant knob morphology, and failure to deliver EMP1 to the red blood cell surface. We show that an expanded low complexity sequence in the C-terminal region of PTP7, identified only in the Laverania clade of Plasmodium, is critical for efficient virulence protein trafficking. We describe a malaria parasite protein, PTP7, involved in virulence factor trafficking that is associated with Maurer’s clefts and other trafficking compartments. Upon disruption of the PTP7 locus, the Maurer’s clefts become decorated with vesicles; the knobby protrusions on the host red blood cell surface are fewer and distorted; and trafficking of the virulence protein, EMP1, to the host red blood cell surface is ablated. We provide evidence that a region of PTP7 with low sequence complexity plays an important role in virulence protein trafficking from the Maurer’s clefts.
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9
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Epigenetics of malaria parasite nutrient uptake, but why? Trends Parasitol 2022; 38:618-628. [PMID: 35641406 PMCID: PMC9283302 DOI: 10.1016/j.pt.2022.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 05/01/2022] [Accepted: 05/10/2022] [Indexed: 11/23/2022]
Abstract
The conserved plasmodial surface anion channel (PSAC) mediates nutrient uptake by bloodstream malaria parasites and is an antimalarial target. This pathogen-associated channel is linked to the clag multigene family, which is variably expanded in Plasmodium spp. Member genes are under complex epigenetic regulation, with the clag3 genes of the human P. falciparum pathogen exhibiting monoallelic transcription and mutually exclusive surface exposure on infected erythrocytes. While other multigene families use monoallelic expression to evade host immunity, the reasons of epigenetic control of clag genes are unclear. I consider existing models and their implications for nutrient acquisition and immune evasion. Understanding the reasons for epigenetic regulation of PSAC-mediated nutrient uptake will help clarify host-pathogen interactions and guide development of therapies resistant to allele switching.
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10
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Pashova S, Balabanski L, Elmadjian G, Savov A, Stoyanova E, Shivarov V, Petrov P, Pashov A. Restriction of the Global IgM Repertoire in Antiphospholipid Syndrome. Front Immunol 2022; 13:865232. [PMID: 35493489 PMCID: PMC9043687 DOI: 10.3389/fimmu.2022.865232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 03/21/2022] [Indexed: 11/22/2022] Open
Abstract
The typical anti-phospholipid antibodies (APLA) in the anti-phospholipid syndrome (APS) are reactive with the phospholipid-binding protein β2GPI as well as a growing list of other protein targets. The relation of APLA to natural antibodies and the fuzzy set of autoantigens involved provoked us to study the changes in the IgM repertoire in APS. To this end, peptides selected by serum IgM from a 7-residue linear peptide phage display library (PDL) were deep sequenced. The analysis was aided by a novel formal representation of the Igome (the mimotope set reflecting the IgM specificities) in the form of a sequence graph. The study involved women with APLA and habitual abortions (n=24) compared to age-matched clinically healthy pregnant women (n=20). Their pooled Igomes (297 028 mimotope sequences) were compared also to the global public repertoire Igome of pooled donor plasma IgM (n=2 796 484) and a set of 7-mer sequences found in the J regions of human immunoglobulins (n=4 433 252). The pooled Igome was represented as a graph connecting the sequences as similar as the mimotopes of the same monoclonal antibody. The criterion was based on previously published data. In the resulting graph, identifiable clusters of vertices were considered related to the footprints of overlapping antibody cross-reactivities. A subgraph based on the clusters with a significant differential expression of APS patients' mimotopes contained predominantly specificities underrepresented in APS. The differentially expressed IgM footprints showed also an increased cross-reactivity with immunoglobulin J regions. The specificities underexpressed in APS had a higher correlation with public specificities than those overexpressed. The APS associated specificities were strongly related also to the human peptidome with 1 072 mimotope sequences found in 7 519 human proteins. These regions were characterized by low complexity. Thus, the IgM repertoire of the APS patients was found to be characterized by a significant reduction of certain public specificities found in the healthy controls with targets representing low complexity linear self-epitopes homologous to human antibody J regions.
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Affiliation(s)
- Shina Pashova
- Institute of Biology and Immunology of Reproduction, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Lubomir Balabanski
- Department of Medical Genetics, Medical University-Sofia, Sofia, Bulgaria
- Genomics Laboratory, Hospital “Malinov”, Sofia, Bulgaria
| | - Gabriel Elmadjian
- Institute of Biology and Immunology of Reproduction, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Alexey Savov
- Department of Medical Genetics, Medical University-Sofia, Sofia, Bulgaria
| | - Elena Stoyanova
- Institute of Biology and Immunology of Reproduction, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | | | - Peter Petrov
- Institute Mathematics and Informatics, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Anastas Pashov
- Institute of Microbiology, Bulgarian Academy of Sciences, Sofia, Bulgaria
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11
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Liu ZSJ, Sattabongkot J, White M, Chotirat S, Kumpitak C, Takashima E, Harbers M, Tham WH, Healer J, Chitnis CE, Tsuboi T, Mueller I, Longley RJ. Naturally acquired antibody kinetics against Plasmodium vivax antigens in people from a low malaria transmission region in western Thailand. BMC Med 2022; 20:89. [PMID: 35260169 PMCID: PMC8904165 DOI: 10.1186/s12916-022-02281-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 02/02/2022] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Plasmodium vivax (P. vivax) is the dominant Plasmodium spp. causing the disease malaria in low-transmission regions outside of Africa. These regions often feature high proportions of asymptomatic patients with sub-microscopic parasitaemia and relapses. Naturally acquired antibody responses are induced after Plasmodium infection, providing partial protection against high parasitaemia and clinical episodes. However, previous work has failed to address the presence and maintenance of such antibody responses to P. vivax particularly in low-transmission regions. METHODS We followed 34 patients in western Thailand after symptomatic P. vivax infections to monitor antibody kinetics over 9 months, during which no recurrent infections occurred. We assessed total IgG, IgG subclass and IgM levels to up to 52 P. vivax proteins every 2-4 weeks using a multiplexed Luminex® assay and identified protein-specific variation in antibody longevity. Mathematical modelling was used to generate the estimated half-life of antibodies, long-, and short-lived antibody-secreting cells. RESULTS Generally, an increase in antibody level was observed within 1-week post symptomatic infection, followed by an exponential decay of different rates. We observed mostly IgG1 dominance and IgG3 sub-dominance in this population. IgM responses followed similar kinetic patterns to IgG, with some proteins unexpectedly inducing long-lived IgM responses. We also monitored antibody responses against 27 IgG-immunogenic antigens in 30 asymptomatic individuals from a similar region. Our results demonstrate that most antigens induced robust and long-lived total IgG responses following asymptomatic infections in the absence of (detected) boosting infections. CONCLUSIONS Our work provides new insights into the development and maintenance of naturally acquired immunity to P. vivax and will guide the potential use of serology to indicate immune status and/or identify populations at risk.
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Affiliation(s)
- Zoe Shih-Jung Liu
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3010, Australia.,Current affiliation: Deakin University, School of Medicine, IMPACT, Institute for Innovation in Physical and Mental Health and Clinical Translation, Geelong, Victoria, 3220, Australia
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Michael White
- Infectious Disease Epidemiology and Analytics G5 Unit, Department of Global Health, Institut Pasteur, Paris, France
| | - Sadudee Chotirat
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chalermpon Kumpitak
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Eizo Takashima
- Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Matthias Harbers
- CellFree Sciences Co., Ltd., Yokohama, Japan and RIKEN Centre for Integrative Medical Sciences, Yokohama, Japan
| | - Wai-Hong Tham
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Julie Healer
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Chetan E Chitnis
- Malaria Parasite Biology and Vaccines, Department of Parasites & Insect Vectors, Institut Pasteur, Paris, France
| | | | - Ivo Mueller
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Rhea J Longley
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia. .,Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3010, Australia.
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12
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Wahl I, Wardemann H. How to induce protective humoral immunity against Plasmodium falciparum circumsporozoite protein. J Exp Med 2022; 219:212951. [PMID: 35006242 PMCID: PMC8754000 DOI: 10.1084/jem.20201313] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 12/03/2021] [Accepted: 12/17/2021] [Indexed: 12/23/2022] Open
Abstract
The induction of protective humoral immune responses against sporozoite surface proteins of the human parasite Plasmodium falciparum (Pf) is a prime goal in the development of a preerythrocytic malaria vaccine. The most promising antibody target is circumsporozoite protein (CSP). Although PfCSP induces strong humoral immune responses upon vaccination, vaccine efficacy is overall limited and not durable. Here, we review recent efforts to gain a better molecular and cellular understanding of anti-PfCSP B cell responses in humans and discuss ways to overcome limitations in the induction of stable titers of high-affinity antibodies that might help to increase vaccine efficacy and promote long-lived protection.
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Affiliation(s)
- Ilka Wahl
- B Cell Immunology, German Cancer Research Center, Heidelberg, Germany
| | - Hedda Wardemann
- B Cell Immunology, German Cancer Research Center, Heidelberg, Germany
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13
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Naung MT, Martin E, Munro J, Mehra S, Guy AJ, Laman M, Harrison GLA, Tavul L, Hetzel M, Kwiatkowski D, Mueller I, Bahlo M, Barry AE. Global diversity and balancing selection of 23 leading Plasmodium falciparum candidate vaccine antigens. PLoS Comput Biol 2022; 18:e1009801. [PMID: 35108259 PMCID: PMC8843232 DOI: 10.1371/journal.pcbi.1009801] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 02/14/2022] [Accepted: 01/03/2022] [Indexed: 12/30/2022] Open
Abstract
Investigation of the diversity of malaria parasite antigens can help prioritize and validate them as vaccine candidates and identify the most common variants for inclusion in vaccine formulations. Studies of vaccine candidates of the most virulent human malaria parasite, Plasmodium falciparum, have focused on a handful of well-known antigens, while several others have never been studied. Here we examine the global diversity and population structure of leading vaccine candidate antigens of P. falciparum using the MalariaGEN Pf3K (version 5.1) resource, comprising more than 2600 genomes from 15 malaria endemic countries. A stringent variant calling pipeline was used to extract high quality antigen gene 'haplotypes' from the global dataset and a new R-package named VaxPack was used to streamline population genetic analyses. In addition, a newly developed algorithm that enables spatial averaging of selection pressure on 3D protein structures was applied to the dataset. We analysed the genes encoding 23 leading and novel candidate malaria vaccine antigens including csp, trap, eba175, ama1, rh5, and CelTOS. Our analysis shows that current malaria vaccine formulations are based on rare haplotypes and thus may have limited efficacy against natural parasite populations. High levels of diversity with evidence of balancing selection was detected for most of the erythrocytic and pre-erythrocytic antigens. Measures of natural selection were then mapped to 3D protein structures to predict targets of functional antibodies. For some antigens, geographical variation in the intensity and distribution of these signals on the 3D structure suggests adaptation to different human host or mosquito vector populations. This study provides an essential framework for the diversity of P. falciparum antigens to be considered in the design of the next generation of malaria vaccines.
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Affiliation(s)
- Myo T. Naung
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Carlton, Victoria, Australia
- Institute of Mental and Physical Health and Clinical Translation (IMPACT), School of Medicine, Deakin University, Geelong, Victoria, Australia
| | - Elijah Martin
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Life Sciences Discipline, Burnet Institute, Melbourne, Victoria, Australia
| | - Jacob Munro
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Somya Mehra
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Life Sciences Discipline, Burnet Institute, Melbourne, Victoria, Australia
| | - Andrew J. Guy
- School of Science, RMIT University, Melbourne, Victoria, Australia
| | - Moses Laman
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - G. L. Abby Harrison
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Carlton, Victoria, Australia
| | - Livingstone Tavul
- Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Manuel Hetzel
- Swiss Tropical Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Dominic Kwiatkowski
- Sanger Institute, Hinxton, United Kingdom
- Big Data Institute, University of Oxford, Oxford, United Kingdom
| | - Ivo Mueller
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Carlton, Victoria, Australia
- Division of Parasites and Insect Vectors, Pasteur Institute, Paris, France
| | - Melanie Bahlo
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Carlton, Victoria, Australia
| | - Alyssa E. Barry
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Carlton, Victoria, Australia
- Institute of Mental and Physical Health and Clinical Translation (IMPACT), School of Medicine, Deakin University, Geelong, Victoria, Australia
- Life Sciences Discipline, Burnet Institute, Melbourne, Victoria, Australia
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14
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Badaya A, Sasidhar YU. The role of temperature in the binding of the disordered epitope region of human thrombopoietin to antibody: A molecular dynamics simulations study. J Mol Graph Model 2021; 111:108098. [PMID: 34871981 DOI: 10.1016/j.jmgm.2021.108098] [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: 04/21/2021] [Revised: 11/11/2021] [Accepted: 11/26/2021] [Indexed: 12/01/2022]
Abstract
The N-terminal domain (163 residues) of Human thrombopoietin (hTPO) is highly conserved and responsible for the receptor-binding. The crystal structure of free hTPO is not yet available, but the crystal structure of its receptor-binding domain (hTPO163) is available in complex with the TN1-Fab antibody. According to a thermodynamic study of hTPO163 binding to TN1-Fab Ab, the ΔH value for binding becomes more negative with an increase in temperature from 283 K to 303 K. The objective of our study is to understand how the free hTPO163 behaves dynamically and to study the effect of temperature on the association of hTPO163 to TN1-Fab antibody through molecular dynamics simulations. We studied the Ag-Ab interactions at two different temperatures 298 K and 303 K. The discontinuous epitope region (residues 98-115) of free hTPO163 displays a conformational switch and it gets stabilized upon binding to the Ab at 303 K. Based on our results, it may be surmised that the epitope region 98-115 is behaving like a disordered epitope. The disordered epitopes are known to be more efficient in binding with the antibody. We also find that, there is an increase in number of hydrogen-bonding interactions and hydrophobic contacts with an increase in the temperature from 298 K to 303 K. Thus, this observation explains a possible reason behind the more negative value of ΔH at the higher temperature 303 K as compared to 298 K.
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Affiliation(s)
- Apoorva Badaya
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Yellamraju U Sasidhar
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
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15
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Shah Z, Naung MT, Moser KA, Adams M, Buchwald AG, Dwivedi A, Ouattara A, Seydel KB, Mathanga DP, Barry AE, Serre D, Laufer MK, Silva JC, Takala-Harrison S. Whole-genome analysis of Malawian Plasmodium falciparum isolates identifies possible targets of allele-specific immunity to clinical malaria. PLoS Genet 2021; 17:e1009576. [PMID: 34033654 PMCID: PMC8184011 DOI: 10.1371/journal.pgen.1009576] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 06/07/2021] [Accepted: 05/04/2021] [Indexed: 12/30/2022] Open
Abstract
Individuals acquire immunity to clinical malaria after repeated Plasmodium falciparum infections. Immunity to disease is thought to reflect the acquisition of a repertoire of responses to multiple alleles in diverse parasite antigens. In previous studies, we identified polymorphic sites within individual antigens that are associated with parasite immune evasion by examining antigen allele dynamics in individuals followed longitudinally. Here we expand this approach by analyzing genome-wide polymorphisms using whole genome sequence data from 140 parasite isolates representing malaria cases from a longitudinal study in Malawi and identify 25 genes that encode possible targets of naturally acquired immunity that should be validated immunologically and further characterized for their potential as vaccine candidates.
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Affiliation(s)
- Zalak Shah
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Myo T. Naung
- Population Health and Immunity Division, Walter Eliza Hall of Medical Institute for Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Carlton, Victoria, Australia
- School of Medicine, Deakin University, Geelong, Victoria, Australia
| | - Kara A. Moser
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Matthew Adams
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Andrea G. Buchwald
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Ankit Dwivedi
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Amed Ouattara
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Karl B. Seydel
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, United States of America
- Blantyre Malaria Project, University of Malawi College of Medicine, Blantyre, Malawi
| | - Don P. Mathanga
- University of Malawi College of Medicine, Malaria Alert Centre, Blantyre, Malawi
| | - Alyssa E. Barry
- Population Health and Immunity Division, Walter Eliza Hall of Medical Institute for Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Carlton, Victoria, Australia
- School of Medicine, Deakin University, Geelong, Victoria, Australia
- Disease Elimination and Maternal and Child Health, Burnet Institute, Melbourne, Victoria, Australia
| | - David Serre
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Miriam K. Laufer
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Joana C. Silva
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Shannon Takala-Harrison
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
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16
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Shey RA, Ghogomu SM, Shintouo CM, Nkemngo FN, Nebangwa DN, Esoh K, Yaah NE, Manka’aFri M, Nguve JE, Ngwese RA, Njume FN, Bertha FA, Ayong L, Njemini R, Vanhamme L, Souopgui J. Computational Design and Preliminary Serological Analysis of a Novel Multi-Epitope Vaccine Candidate against Onchocerciasis and Related Filarial Diseases. Pathogens 2021; 10:99. [PMID: 33494344 PMCID: PMC7912539 DOI: 10.3390/pathogens10020099] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/14/2021] [Accepted: 01/18/2021] [Indexed: 11/16/2022] Open
Abstract
: Onchocerciasis is a skin and eye disease that exerts a heavy socio-economic burden, particularly in sub-Saharan Africa, a region which harbours greater than 96% of either infected or at-risk populations. The elimination plan for the disease is currently challenged by many factors including amongst others; the potential emergence of resistance to the main chemotherapeutic agent, ivermectin (IVM). Novel tools, including preventative and therapeutic vaccines, could provide additional impetus to the disease elimination tool portfolio. Several observations in both humans and animals have provided evidence for the development of both natural and artificial acquired immunity. In this study, immuno-informatics tools were applied to design a filarial-conserved multi-epitope subunit vaccine candidate, (designated Ov-DKR-2) consisting of B-and T-lymphocyte epitopes of eight immunogenic antigens previously assessed in pre-clinical studies. The high-percentage conservation of the selected proteins and epitopes predicted in related nematode parasitic species hints that the generated chimera may be instrumental for cross-protection. Bioinformatics analyses were employed for the prediction, refinement, and validation of the 3D structure of the Ov-DKR-2 chimera. In-silico immune simulation projected significantly high levels of IgG1, T-helper, T-cytotoxic cells, INF-γ, and IL-2 responses. Preliminary immunological analyses revealed that the multi-epitope vaccine candidate reacted with antibodies in sera from both onchocerciasis-infected individuals, endemic normals as well as loiasis-infected persons but not with the control sera from European individuals. These results support the premise for further characterisation of the engineered protein as a vaccine candidate for onchocerciasis.
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Affiliation(s)
- Robert Adamu Shey
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea 99999, Cameroon; (R.A.S.); (S.M.G.); (C.M.S.); (D.N.N.); (N.E.Y.); (M.M.); (J.E.N.); (R.A.N.); (F.N.N.)
- Department of Molecular Biology, Institute of Biology and Molecular Medicine, IBMM, Université Libre de Bruxelles, Gosselies Campus, 6040 Gosselies, Belgium;
| | - Stephen Mbigha Ghogomu
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea 99999, Cameroon; (R.A.S.); (S.M.G.); (C.M.S.); (D.N.N.); (N.E.Y.); (M.M.); (J.E.N.); (R.A.N.); (F.N.N.)
| | - Cabirou Mounchili Shintouo
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea 99999, Cameroon; (R.A.S.); (S.M.G.); (C.M.S.); (D.N.N.); (N.E.Y.); (M.M.); (J.E.N.); (R.A.N.); (F.N.N.)
- Frailty in Ageing Research Group, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium;
- Department of Gerontology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium
| | - Francis Nongley Nkemngo
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Buea 99999, Cameroon;
- Centre for Research in Infectious Diseases (CRID), Department of Parasitology and Medical Entomology, Yaounde BP 13591, Cameroon
| | - Derrick Neba Nebangwa
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea 99999, Cameroon; (R.A.S.); (S.M.G.); (C.M.S.); (D.N.N.); (N.E.Y.); (M.M.); (J.E.N.); (R.A.N.); (F.N.N.)
| | - Kevin Esoh
- Division of Human Genetics, Health Sciences Campus, Department of Pathology, University of Cape Town, Anzio Rd, Observatory, Cape Town 7925, South Africa;
| | - Ntang Emmaculate Yaah
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea 99999, Cameroon; (R.A.S.); (S.M.G.); (C.M.S.); (D.N.N.); (N.E.Y.); (M.M.); (J.E.N.); (R.A.N.); (F.N.N.)
| | - Muyanui Manka’aFri
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea 99999, Cameroon; (R.A.S.); (S.M.G.); (C.M.S.); (D.N.N.); (N.E.Y.); (M.M.); (J.E.N.); (R.A.N.); (F.N.N.)
| | - Joel Ebai Nguve
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea 99999, Cameroon; (R.A.S.); (S.M.G.); (C.M.S.); (D.N.N.); (N.E.Y.); (M.M.); (J.E.N.); (R.A.N.); (F.N.N.)
| | - Roland Akwelle Ngwese
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea 99999, Cameroon; (R.A.S.); (S.M.G.); (C.M.S.); (D.N.N.); (N.E.Y.); (M.M.); (J.E.N.); (R.A.N.); (F.N.N.)
| | - Ferdinand Ngale Njume
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea 99999, Cameroon; (R.A.S.); (S.M.G.); (C.M.S.); (D.N.N.); (N.E.Y.); (M.M.); (J.E.N.); (R.A.N.); (F.N.N.)
- Department of Molecular Biology, Institute of Biology and Molecular Medicine, IBMM, Université Libre de Bruxelles, Gosselies Campus, 6040 Gosselies, Belgium;
| | - Fru Asa Bertha
- Department of Public Health and Hygiene, Faculty of Health Science, University of Buea, Buea 99999, Cameroon;
| | - Lawrence Ayong
- Malaria Research Unit, Centre Pasteur Cameroon, Yaoundé Rue 2005, Cameroon;
| | - Rose Njemini
- Frailty in Ageing Research Group, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium;
- Department of Gerontology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium
| | - Luc Vanhamme
- Department of Molecular Biology, Institute of Biology and Molecular Medicine, IBMM, Université Libre de Bruxelles, Gosselies Campus, 6040 Gosselies, Belgium;
| | - Jacob Souopgui
- Department of Molecular Biology, Institute of Biology and Molecular Medicine, IBMM, Université Libre de Bruxelles, Gosselies Campus, 6040 Gosselies, Belgium;
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17
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Discovery of four new B-cell protective epitopes for malaria using Q beta virus-like particle as platform. NPJ Vaccines 2020; 5:92. [PMID: 33083027 PMCID: PMC7546618 DOI: 10.1038/s41541-020-00242-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 09/17/2020] [Indexed: 12/26/2022] Open
Abstract
Malaria remains one of the world’s most urgent global health problems, with almost half a million deaths and hundreds of millions of clinical cases each year. Existing interventions by themselves will not be enough to tackle infection in high-transmission areas. The best new intervention would be an effective vaccine; but the leading P. falciparum and P. vivax vaccine candidates, RTS,S and VMP001, show only modest to low field efficacy. New antigens and improved ways for screening antigens for protective efficacy will be required. This study exploits the potential of Virus-Like Particles (VLP) to enhance immune responses to antigens, the ease of coupling peptides to the Q beta (Qβ) VLP and the existing murine malaria challenge to screen B-cell epitopes for protective efficacy. We screened P. vivax TRAP (PvTRAP) immune sera against individual 20-mer PvTRAP peptides. The most immunogenic peptides associated with protection were loaded onto Qβ VLPs to assess protective efficacy in a malaria sporozoite challenge. A second approach focused on identifying conserved regions within known sporozoite invasion proteins and assessing them as part of the Qβ. Using this VLP as a peptide scaffold, four new protective B-cell epitopes were discovered: three from the disordered region of PvTRAP and one from Thrombospondin-related sporozoite protein (TRSP). Antigenic interference between these and other B-cell epitopes was also explored using the virus-like particle/peptide platform. This approach demonstrates the utility of VLPs to help identifying new B-cell epitopes for inclusion in next-generation malaria vaccines.
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18
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Wang Y, Yang HJ, Harrison PM. The relationship between protein domains and homopeptides in the Plasmodium falciparum proteome. PeerJ 2020; 8:e9940. [PMID: 33062426 PMCID: PMC7534687 DOI: 10.7717/peerj.9940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/24/2020] [Indexed: 12/03/2022] Open
Abstract
The proteome of the malaria parasite Plasmodium falciparum is notable for the pervasive occurrence of homopeptides or low-complexity regions (i.e., regions that are made from a small subset of amino-acid residue types). The most prevalent of these are made from residues encoded by adenine/thymidine (AT)-rich codons, in particular asparagine. We examined homopeptide occurrences within protein domains in P. falciparum. Homopeptide enrichments occur for hydrophobic (e.g., valine), or small residues (alanine or glycine) in short spans (<5 residues), but these enrichments disappear for longer lengths. We observe that short asparagine homopeptides (<10 residues long) have a dramatic relative depletion inside protein domains, indicating some selective constraint to keep them from forming. We surmise that this is possibly linked to co-translational protein folding, although there are specific protein domains that are enriched in longer asparagine homopeptides (≥10 residues) indicating a functional linkage for specific poly-asparagine tracts. Top gene ontology functional category enrichments for homopeptides associated with diverse protein domains include “vesicle-mediated transport”, and “DNA-directed 5′-3′ RNA polymerase activity”, with various categories linked to “binding” evidencing significant homopeptide depletions. Also, in general homopeptides are substantially enriched in the parts of protein domains that are near/in IDRs. The implications of these findings are discussed.
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Kumar A, Kumar P, Saumya KU, Kapuganti SK, Bhardwaj T, Giri R. Exploring the SARS-CoV-2 structural proteins for multi-epitope vaccine development: an in-silico approach. Expert Rev Vaccines 2020; 19:887-898. [PMID: 32815406 PMCID: PMC7544969 DOI: 10.1080/14760584.2020.1813576] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 08/13/2020] [Indexed: 12/17/2022]
Abstract
INTRODUCTION The ongoing life-threatening pandemic of coronavirus disease 2019 (COVID-19) has extensively affected the world. During this global health crisis, it is fundamentally crucial to find strategies to combat SARS-CoV-2. Despite several efforts in this direction and continuing clinical trials, no vaccine has been approved for it yet. METHODS To find a preventive measure, we have computationally designed a multi-epitopic subunit vaccine using immuno-informatic approaches. RESULTS The structural proteins of SARS-CoV-2 involved in its survival and pathogenicity were used to predict antigenic epitopes. The antigenic epitopes were capable of eliciting a strong humoral as well as cell-mediated immune response, our predictions suggest. The final vaccine was constructed by joining the all epitopes with specific linkers and to enhance their stability and immunogenicity. The physicochemical property of the vaccine was assessed. The vaccine 3D structure prediction and validation were done and docked with the human TLR-3 receptor. Furthermore, molecular dynamics simulations of the vaccine-TLR-3 receptor complex are employed to assess its dynamic motions and binding stability in-silico. CONCLUSION Based on this study, we strongly suggest synthesizing this vaccine, which further can be tested in-vitro and in-vivo to check its potency in a cure for COVID-19.
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Affiliation(s)
- Amit Kumar
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, India
| | - Prateek Kumar
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, India
| | - Kumar Udit Saumya
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, India
| | | | - Taniya Bhardwaj
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, India
| | - Rajanish Giri
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, India
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20
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Zheng Z, Mergaert AM, Fahmy LM, Bawadekar M, Holmes CL, Ong IM, Bridges AJ, Newton MA, Shelef MA. Disordered Antigens and Epitope Overlap Between Anti-Citrullinated Protein Antibodies and Rheumatoid Factor in Rheumatoid Arthritis. Arthritis Rheumatol 2019; 72:262-272. [PMID: 31397047 DOI: 10.1002/art.41074] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 08/06/2019] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Anti-citrullinated protein antibodies (ACPAs) and rheumatoid factor (RF) are commonly present in rheumatoid arthritis (RA) without a clear rationale for their coexistence. Moreover, autoantibodies develop against proteins with different posttranslational modifications and native proteins without obvious unifying characteristics of the antigens. We undertook this study to broadly evaluate autoantibody binding in seronegative and seropositive RA to identify novel features of reactivity. METHODS An array was created using a total of 172,828 native peptides, citrulline-containing peptides, and homocitrulline-containing peptides derived primarily from proteins citrullinated in the rheumatoid joint. IgG and IgM binding to peptides were compared between cyclic citrullinated peptide (CCP)-positive RF+, CCP+RF-, CCP-RF+, and CCP-RF- serum from RA patients (n = 48) and controls (n = 12). IgG-bound and endogenously citrullinated peptides were analyzed for amino acid patterns and predictors of intrinsic disorder, i.e., unstable 3-dimensional structure. Binding to IgG-derived peptides was specifically evaluated. Enzyme-linked immunosorbent assay confirmed key results. RESULTS Broadly, CCP+RF+ patients had high citrulline-specific IgG binding to array peptides and CCP+RF- and CCP-RF+ patients had modest citrulline-specific IgG binding (median Z scores 3.02, 1.42, and 0.75, respectively; P < 0.0001). All RA groups had low homocitrulline-specific binding. CCP+RF+ patients had moderate IgG binding to native peptides (median Z score 2.38; P < 0.0001). The highest IgG binding was to citrulline-containing peptides, irrespective of protein identity, especially if citrulline was adjacent to glycine or serine, motifs also seen in endogenous citrullination in the rheumatoid joint. Highly bound peptides had multiple features predictive of disorder. IgG from CCP+RF+ patients targeted citrulline-containing IgG-derived peptides. CONCLUSION Disordered antigens, which are frequently citrullinated, and common epitopes for ACPAs and RF are potentially unifying features for RA autoantibodies.
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Affiliation(s)
| | | | | | | | | | - Irene M Ong
- University of Wisconsin-Madison and University of Wisconsin Carbone Comprehensive Cancer Center
| | - Alan J Bridges
- University of Wisconsin-Madison and William S. Middleton Memorial Veterans Hospital
| | | | - Miriam A Shelef
- University of Wisconsin-Madison and William S. Middleton Memorial Veterans Hospital
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21
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Sormanni P, Aprile FA, Vendruscolo M. Third generation antibody discovery methods: in silico rational design. Chem Soc Rev 2018; 47:9137-9157. [PMID: 30298157 DOI: 10.1039/c8cs00523k] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Owing to their outstanding performances in molecular recognition, antibodies are extensively used in research and applications in molecular biology, biotechnology and medicine. Recent advances in experimental and computational methods are making it possible to complement well-established in vivo (first generation) and in vitro (second generation) methods of antibody discovery with novel in silico (third generation) approaches. Here we describe the principles of computational antibody design and review the state of the art in this field. We then present Modular, a method that implements the rational design of antibodies in a modular manner, and describe the opportunities offered by this approach.
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Affiliation(s)
- Pietro Sormanni
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK.
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22
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Modulation of the aggregation of an amyloidogenic sequence by flanking-disordered region in the intrinsically disordered antigen merozoite surface protein 2. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2018; 48:99-110. [PMID: 30443712 DOI: 10.1007/s00249-018-1337-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 08/31/2018] [Accepted: 11/08/2018] [Indexed: 10/27/2022]
Abstract
The abundant Plasmodium falciparum merozoite surface protein MSP2, a potential malaria vaccine candidate, is an intrinsically disordered protein with some nascent secondary structure present in its conserved N-terminal region. This relatively ordered region has been implicated in both membrane interactions and amyloid-like aggregation of the protein, while the significance of the flanking-disordered region is unclear. In this study, we show that aggregation of the N-terminal conserved region of MSP2 is influenced in a length- and sequence-dependent fashion by the disordered central variable sequences. Intriguingly, MSP2 peptides containing the conserved region and the first five residues of the variable disordered regions aggregated more rapidly than a peptide corresponding to the conserved region alone. In contrast, MSP2 peptides extending 8 or 12 residues into the disordered region aggregated more slowly, consistent with the expected inhibitory effect of flanking-disordered sequences on the aggregation of amyloidogenic ordered sequences. Computational analyses indicated that the helical propensity of the ordered region of MSP2 was modulated by the adjacent disordered five residues in a sequence-dependent manner. Nuclear magnetic resonance and circular dichroism spectroscopic studies with synthetic peptides confirmed the computational predictions, emphasizing the correlation between aggregation propensity and conformation of the ordered region and the effects thereon of the adjacent disordered region. These results show that the effects of flanking-disordered sequences on a more ordered sequence may include enhancement of aggregation through modulation of the conformational properties of the more ordered sequence.
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23
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Large-Scale Analyses of Site-Specific Evolutionary Rates across Eukaryote Proteomes Reveal Confounding Interactions between Intrinsic Disorder, Secondary Structure, and Functional Domains. Genes (Basel) 2018; 9:genes9110553. [PMID: 30441862 PMCID: PMC6265720 DOI: 10.3390/genes9110553] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 11/09/2018] [Accepted: 11/09/2018] [Indexed: 12/31/2022] Open
Abstract
Various structural and functional constraints govern the evolution of protein sequences. As a result, the relative rates of amino acid replacement among sites within a protein can vary significantly. Previous large-scale work on Metazoan (Animal) protein sequence alignments indicated that amino acid replacement rates are partially driven by a complex interaction among three factors: intrinsic disorder propensity; secondary structure; and functional domain involvement. Here, we use sequence-based predictors to evaluate the effects of these factors on site-specific sequence evolutionary rates within four eukaryotic lineages: Metazoans; Plants; Saccharomycete Fungi; and Alveolate Protists. Our results show broad, consistent trends across all four Eukaryote groups. In all four lineages, there is a significant increase in amino acid replacement rates when comparing: (i) disordered vs. ordered sites; (ii) random coil sites vs. sites in secondary structures; and (iii) inter-domain linker sites vs. sites in functional domains. Additionally, within Metazoans, Plants, and Saccharomycetes, there is a strong confounding interaction between intrinsic disorder and secondary structure-alignment sites exhibiting both high disorder propensity and involvement in secondary structures have very low average rates of sequence evolution. Analysis of gene ontology (GO) terms revealed that in all four lineages, a high fraction of sequences containing these conserved, disordered-structured sites are involved in nucleic acid binding. We also observe notable differences in the statistical trends of Alveolates, where intrinsically disordered sites are more variable than in other Eukaryotes and the statistical interactions between disorder and other factors are less pronounced.
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24
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Oyen D, Torres JL, Cottrell CA, Richter King C, Wilson IA, Ward AB. Cryo-EM structure of P. falciparum circumsporozoite protein with a vaccine-elicited antibody is stabilized by somatically mutated inter-Fab contacts. SCIENCE ADVANCES 2018; 4:eaau8529. [PMID: 30324137 PMCID: PMC6179375 DOI: 10.1126/sciadv.aau8529] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 09/07/2018] [Indexed: 05/29/2023]
Abstract
The circumsporozoite protein (CSP) on the surface of Plasmodium falciparum sporozoites is important for parasite development, motility, and host hepatocyte invasion. However, intrinsic disorder of the NANP repeat sequence in the central region of CSP has hindered its structural and functional characterization. Here, the cryo-electron microscopy structure at ~3.4-Å resolution of a recombinant shortened CSP construct with the variable domains (Fabs) of a highly protective monoclonal antibody reveals an extended spiral conformation of the central NANP repeat region surrounded by antibodies. This unusual structure appears to be stabilized and/or induced by interaction with an antibody where contacts between adjacent Fabs are somatically mutated and enhance the interaction. This maturation in non-antigen contact residues may be an effective mechanism for antibodies to target tandem repeat sequences and provide novel insights into malaria vaccine design.
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Affiliation(s)
- David Oyen
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jonathan L. Torres
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Christopher A. Cottrell
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - C. Richter King
- PATH’s Malaria Vaccine Initiative, PATH’s Center for Vaccine Innovation and Access, Washington, DC 20001, USA
| | - Ian A. Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Andrew B. Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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25
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A disordered acidic domain in GPIHBP1 harboring a sulfated tyrosine regulates lipoprotein lipase. Proc Natl Acad Sci U S A 2018; 115:E6020-E6029. [PMID: 29899144 DOI: 10.1073/pnas.1806774115] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The intravascular processing of triglyceride-rich lipoproteins depends on lipoprotein lipase (LPL) and GPIHBP1, a membrane protein of endothelial cells that binds LPL within the subendothelial spaces and shuttles it to the capillary lumen. In the absence of GPIHBP1, LPL remains mislocalized within the subendothelial spaces, causing severe hypertriglyceridemia (chylomicronemia). The N-terminal domain of GPIHBP1, an intrinsically disordered region (IDR) rich in acidic residues, is important for stabilizing LPL's catalytic domain against spontaneous and ANGPTL4-catalyzed unfolding. Here, we define several important properties of GPIHBP1's IDR. First, a conserved tyrosine in the middle of the IDR is posttranslationally modified by O-sulfation; this modification increases both the affinity of GPIHBP1-LPL interactions and the ability of GPIHBP1 to protect LPL against ANGPTL4-catalyzed unfolding. Second, the acidic IDR of GPIHBP1 increases the probability of a GPIHBP1-LPL encounter via electrostatic steering, increasing the association rate constant (kon) for LPL binding by >250-fold. Third, we show that LPL accumulates near capillary endothelial cells even in the absence of GPIHBP1. In wild-type mice, we expect that the accumulation of LPL in close proximity to capillaries would increase interactions with GPIHBP1. Fourth, we found that GPIHBP1's IDR is not a key factor in the pathogenicity of chylomicronemia in patients with the GPIHBP1 autoimmune syndrome. Finally, based on biophysical studies, we propose that the negatively charged IDR of GPIHBP1 traverses a vast space, facilitating capture of LPL by capillary endothelial cells and simultaneously contributing to GPIHBP1's ability to preserve LPL structure and activity.
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26
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Krishnarjuna B, Sugiki T, Morales RAV, Seow J, Fujiwara T, Wilde KL, Norton RS, MacRaild CA. Transient antibody-antigen interactions mediate the strain-specific recognition of a conserved malaria epitope. Commun Biol 2018; 1:58. [PMID: 30271940 PMCID: PMC6123721 DOI: 10.1038/s42003-018-0063-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 05/07/2018] [Indexed: 01/09/2023] Open
Abstract
Transient interactions in which binding partners retain substantial conformational disorder play an essential role in regulating biological networks, challenging the expectation that specificity demands structurally defined and unambiguous molecular interactions. The monoclonal antibody 6D8 recognises a completely conserved continuous nine-residue epitope within the intrinsically disordered malaria antigen, MSP2, yet it has different affinities for the two allelic forms of this antigen. NMR chemical shift perturbations, relaxation rates and paramagnetic relaxation enhancements reveal the presence of transient interactions involving polymorphic residues immediately C-terminal to the structurally defined epitope. A combination of these experimental data with molecular dynamics simulations shows clearly that the polymorphic C-terminal extension engages in multiple transient interactions distributed across much of the accessible antibody surface. These interactions are determined more by topographical features of the antibody surface than by sequence-specific interactions. Thus, specificity arises as a consequence of subtle differences in what are highly dynamic and essentially non-specific interactions.
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Affiliation(s)
- Bankala Krishnarjuna
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Toshihiko Sugiki
- Laboratory of Molecular Biophysics, Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Rodrigo A V Morales
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Jeffrey Seow
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Toshimichi Fujiwara
- Laboratory of Molecular Biophysics, Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Karyn L Wilde
- National Deuteration Facility, Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, NSW, 2234, Australia
| | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia.
| | - Christopher A MacRaild
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia.
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27
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MacRaild CA, Seow J, Das SC, Norton RS. Disordered epitopes as peptide vaccines. Pept Sci (Hoboken) 2018; 110:e24067. [PMID: 32328540 PMCID: PMC7167742 DOI: 10.1002/pep2.24067] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 03/08/2018] [Accepted: 03/09/2018] [Indexed: 01/23/2023]
Abstract
The development of clinically useful peptide-based vaccines remains a long-standing goal. This review highlights that intrinsically disordered protein antigens, which lack an ordered three-dimensional structure, represent excellent starting points for the development of such vaccines. Disordered proteins represent an important class of antigen in a wide range of human pathogens, and, contrary to widespread belief, they are frequently targets of protective antibody responses. Importantly, disordered epitopes appear invariably to be linear epitopes, rendering them ideally suited to incorporation into a peptide vaccine. Nonetheless, the conformational properties of disordered antigens, and hence their recognition by antibodies, frequently depend on the interactions they make and the context in which they are presented to the immune system. These effects must be considered in the design of an effective vaccine. Here we discuss these issues and propose design principles that may facilitate the development of peptide vaccines targeting disordered antigens.
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Affiliation(s)
- Christopher A. MacRaild
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal ParadeParkville3052Australia
| | - Jeffrey Seow
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal ParadeParkville3052Australia
| | - Sreedam C. Das
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal ParadeParkville3052Australia
| | - Raymond S. Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal ParadeParkville3052Australia
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28
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Singh SK, Tiendrebeogo RW, Chourasia BK, Kana IH, Singh S, Theisen M. Lactococcus lactis provides an efficient platform for production of disulfide-rich recombinant proteins from Plasmodium falciparum. Microb Cell Fact 2018; 17:55. [PMID: 29618355 PMCID: PMC5885415 DOI: 10.1186/s12934-018-0902-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 03/27/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The production of recombinant proteins with proper conformation, appropriate post-translational modifications in an easily scalable and cost-effective system is challenging. Lactococcus lactis has recently been identified as an efficient Gram positive cell factory for the production of recombinant protein. We and others have used this expression host for the production of selected malaria vaccine candidates. The safety of this production system has been confirmed in multiple clinical trials. Here we have explored L. lactis cell factories for the production of 31 representative Plasmodium falciparum antigens with varying sizes (ranging from 9 to 90 kDa) and varying degree of predicted structural complexities including eleven antigens with multiple predicted structural disulfide bonds, those which are considered difficult-to-produce proteins. RESULTS Of the 31 recombinant constructs attempted in the L. lactis expression system, the initial expression efficiency was 55% with 17 out of 31 recombinant gene constructs producing high levels of secreted recombinant protein. The majority of the constructs which failed to produce a recombinant protein were found to consist of multiple intra-molecular disulfide-bonds. We found that these disulfide-rich constructs could be produced in high yields when genetically fused to an intrinsically disorder protein domain (GLURP-R0). By exploiting the distinct biophysical and structural properties of the intrinsically disordered protein region we developed a simple heat-based strategy for fast purification of the disulfide-rich protein domains in yields ranging from 1 to 40 mg/l. CONCLUSIONS A novel procedure for the production and purification of disulfide-rich recombinant proteins in L. lactis is described.
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Affiliation(s)
- Susheel K Singh
- Department for Congenital Disorders, Statens Serum Institut, Artillerivej 5, 2300, Copenhagen S, Denmark.,Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Régis Wendpayangde Tiendrebeogo
- Department for Congenital Disorders, Statens Serum Institut, Artillerivej 5, 2300, Copenhagen S, Denmark.,Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Bishwanath Kumar Chourasia
- Department for Congenital Disorders, Statens Serum Institut, Artillerivej 5, 2300, Copenhagen S, Denmark.,Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Ikhlaq Hussain Kana
- Department for Congenital Disorders, Statens Serum Institut, Artillerivej 5, 2300, Copenhagen S, Denmark.,Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Subhash Singh
- Indian Institute of Integrative Medicine, Jammu, India
| | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Artillerivej 5, 2300, Copenhagen S, Denmark. .,Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark. .,Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
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29
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Davies HM, Nofal SD, McLaughlin EJ, Osborne AR. Repetitive sequences in malaria parasite proteins. FEMS Microbiol Rev 2018; 41:923-940. [PMID: 29077880 DOI: 10.1093/femsre/fux046] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 09/13/2017] [Indexed: 12/13/2022] Open
Abstract
Five species of parasite cause malaria in humans with the most severe disease caused by Plasmodium falciparum. Many of the proteins encoded in the P. falciparum genome are unusually enriched in repetitive low-complexity sequences containing a limited repertoire of amino acids. These repetitive sequences expand and contract dynamically and are among the most rapidly changing sequences in the genome. The simplest repetitive sequences consist of single amino acid repeats such as poly-asparagine tracts that are found in approximately 25% of P. falciparum proteins. More complex repeats of two or more amino acids are also common in diverse parasite protein families. There is no universal explanation for the occurrence of repetitive sequences and it is possible that many confer no function to the encoded protein and no selective advantage or disadvantage to the parasite. However, there are increasing numbers of examples where repetitive sequences are important for parasite protein function. We discuss the diverse roles of low-complexity repetitive sequences throughout the parasite life cycle, from mediating protein-protein interactions to enabling the parasite to evade the host immune system.
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Affiliation(s)
- Heledd M Davies
- The Francis Crick Institute, London, NW1 1AT, United Kingdom
| | - Stephanie D Nofal
- London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom
| | - Emilia J McLaughlin
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Andrew R Osborne
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom.,Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, Malet Street, London, WC1E 7HX, United Kingdom
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30
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Abstract
Humoral immune responses against the malaria parasite are an important component of a protective immune response. Antibodies are often directed towards conformational epitopes, and the native structure of the antigenic region is usually critical for antibody recognition. We examined the structural features of various Plasmodium antigens that may impact on epitope location, by performing a comprehensive analysis of known and modelled structures from P. falciparum. Examining the location of known polymorphisms over all available structures, we observed a strong propensity for polymorphic residues to be exposed on the surface and to occur in particular secondary structure segments such as hydrogen-bonded turns. We also utilised established prediction algorithms for B-cell epitopes and MHC class II binding peptides, examining predicted epitopes in relation to known polymorphic sites within structured regions. Finally, we used the available structures to examine polymorphic hotspots and Tajima's D values using a spatial averaging approach. We identified a region of PfAMA1 involving both domains II and III under a high degree of balancing selection relative to the rest of the protein. In summary, we developed general methods for examining how sequence-based features relate to one another in three-dimensional space and applied these methods to key P. falciparum antigens.
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31
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Structural basis for antibody recognition of the NANP repeats in Plasmodium falciparum circumsporozoite protein. Proc Natl Acad Sci U S A 2017; 114:E10438-E10445. [PMID: 29138320 PMCID: PMC5715787 DOI: 10.1073/pnas.1715812114] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The Plasmodium falciparum circumsporozoite protein (CSP) has been studied for decades as a potential immunogen, but little structural information is available on how antibodies recognize the immunodominant NANP repeats within CSP. The most advanced vaccine candidate is RTS,S, which includes multiple NANP repeats. Here, we analyzed two functional antibodies from an RTS,S trial and determined the number of repeats that interact with the antibody Fab fragments using isothermal titration calorimetry and X-ray crystallography. Using negative-stain electron microscopy, we also established how the antibody binds to the NANP repeat region in a recombinant CSP construct. The structural features outlined here provide a rationale for structure-based immunogen design to improve upon the efficacy of the current RTS,S vaccine. Acquired resistance against antimalarial drugs has further increased the need for an effective malaria vaccine. The current leading candidate, RTS,S, is a recombinant circumsporozoite protein (CSP)-based vaccine against Plasmodium falciparum that contains 19 NANP repeats followed by a thrombospondin repeat domain. Although RTS,S has undergone extensive clinical testing and has progressed through phase III clinical trials, continued efforts are underway to enhance its efficacy and duration of protection. Here, we determined that two monoclonal antibodies (mAbs 311 and 317), isolated from a recent controlled human malaria infection trial exploring a delayed fractional dose, inhibit parasite development in vivo by at least 97%. Crystal structures of antibody fragments (Fabs) 311 and 317 with an (NPNA)3 peptide illustrate their different binding modes. Notwithstanding, one and three of the three NPNA repeats adopt similar well-defined type I β-turns with Fab311 and Fab317, respectively. Furthermore, to explore antibody binding in the context of P. falciparum CSP, we used negative-stain electron microscopy on a recombinant shortened CSP (rsCSP) construct saturated with Fabs. Both complexes display a compact rsCSP with multiple Fabs bound, with the rsCSP–Fab311 complex forming a highly organized helical structure. Together, these structural insights may aid in the design of a next-generation malaria vaccine.
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In-silico screening, identification and validation of a novel vaccine candidate in the fight against Plasmodium falciparum. Parasitol Res 2017; 116:1293-1305. [DOI: 10.1007/s00436-017-5408-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 02/08/2017] [Indexed: 12/14/2022]
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Seow J, Morales RAV, MacRaild CA, Krishnarjuna B, McGowan S, Dingjan T, Jaipuria G, Rouet R, Wilde KL, Atreya HS, Richards JS, Anders RF, Christ D, Drinkwater N, Norton RS. Structure and Characterisation of a Key Epitope in the Conserved C-Terminal Domain of the Malaria Vaccine Candidate MSP2. J Mol Biol 2017; 429:836-846. [PMID: 28189425 DOI: 10.1016/j.jmb.2017.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 01/22/2017] [Accepted: 02/05/2017] [Indexed: 10/20/2022]
Abstract
Merozoite surface protein 2 (MSP2) is an intrinsically disordered antigen that is abundant on the surface of the malaria parasite Plasmodium falciparum. The two allelic families of MSP2, 3D7 and FC27, differ in their central variable regions, which are flanked by highly conserved C-terminal and N-terminal regions. In a vaccine trial, full-length 3D7 MSP2 induced a strain-specific protective immune response despite the detectable presence of conserved region antibodies. This work focuses on the conserved C-terminal region of MSP2, which includes the only disulphide bond in the protein and encompasses key epitopes recognised by the mouse monoclonal antibodies 4D11 and 9H4. Although the 4D11 and 9H4 epitopes are overlapping, immunofluorescence assays have shown that the mouse monoclonal antibody 4D11 binds to MSP2 on the merozoite surface with a much stronger signal than 9H4. Understanding the structural basis for this antigenic difference between these antibodies will help direct the design of a broad-spectrum and MSP2-based malaria vaccine. 4D11 and 9H4 were reengineered into antibody fragments [variable region fragment (Fv) and single-chain Fv (scFv)] and were validated as suitable models for their full-sized IgG counterparts by surface plasmon resonance and isothermal titration calorimetry. An alanine scan of the 13-residue epitope 3D7-MSP2207-222 identified the minimal binding epitope of 4D11 and the key residues involved in binding. A 2.2-Å crystal structure of 4D11 Fv bound to the eight-residue epitope NKENCGAA provided valuable insight into the possible conformation of the C-terminal region of MSP2 on the parasite. This work underpins continued efforts to optimise recombinant MSP2 constructs for evaluation as potential vaccine candidates.
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Affiliation(s)
- Jeffrey Seow
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Australia
| | - Rodrigo A V Morales
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Australia
| | - Christopher A MacRaild
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Australia
| | - Bankala Krishnarjuna
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Australia
| | - Sheena McGowan
- Department of Microbiology, Monash University, Clayton 3168, Australia
| | - Tamir Dingjan
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Australia
| | - Garima Jaipuria
- NMR Research Centre, Indian Institute of Science, Bangalore, 560012, India
| | - Romain Rouet
- Garvan Institute of Medical Research, Darlinghurst 2010, Australia
| | - Karyn L Wilde
- National Deuteration Facility, Australian Nuclear Science and Technology Organisation, Lucas Heights 2234, Australia
| | - Hanudatta S Atreya
- NMR Research Centre, Indian Institute of Science, Bangalore, 560012, India
| | - Jack S Richards
- Centre for Biomedical Research, The Burnet Institute, Melbourne 3004, Australia
| | - Robin F Anders
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Australia
| | - Daniel Christ
- Garvan Institute of Medical Research, Darlinghurst 2010, Australia
| | - Nyssa Drinkwater
- Department of Microbiology, Monash University, Clayton 3168, Australia
| | - Raymond S Norton
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Australia.
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Davies HM, Thalassinos K, Osborne AR. Expansion of Lysine-rich Repeats in Plasmodium Proteins Generates Novel Localization Sequences That Target the Periphery of the Host Erythrocyte. J Biol Chem 2016; 291:26188-26207. [PMID: 27777305 PMCID: PMC5207086 DOI: 10.1074/jbc.m116.761213] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Indexed: 01/05/2023] Open
Abstract
Repetitive low complexity sequences, mostly assumed to have no function, are common in proteins that are exported by the malaria parasite into its host erythrocyte. We identify a group of exported proteins containing short lysine-rich tandemly repeated sequences that are sufficient to localize to the erythrocyte periphery, where key virulence-related modifications to the plasma membrane and the underlying cytoskeleton are known to occur. Efficiency of targeting is dependent on repeat number, indicating that novel targeting modules could evolve by expansion of short lysine-rich sequences. Indeed, analysis of fragments of GARP from different species shows that two novel targeting sequences have arisen via the process of repeat expansion in this protein. In the protein Hyp12, the targeting function of a lysine-rich sequence is masked by a neighboring repetitive acidic sequence, further highlighting the importance of repetitive low complexity sequences. We show that sequences capable of targeting the erythrocyte periphery are present in at least nine proteins from Plasmodium falciparum and one from Plasmodium knowlesi. We find these sequences in proteins known to be involved in erythrocyte rigidification and cytoadhesion as well as in previously uncharacterized exported proteins. Together, these data suggest that expansion and contraction of lysine-rich repeats could generate targeting sequences de novo as well as modulate protein targeting efficiency and function in response to selective pressure.
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Affiliation(s)
- Heledd M Davies
- From the Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck and University College London, London WC1E 6BT, United Kingdom
| | - Konstantinos Thalassinos
- From the Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck and University College London, London WC1E 6BT, United Kingdom
| | - Andrew R Osborne
- From the Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck and University College London, London WC1E 6BT, United Kingdom
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