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Bektas S, Kaptan E. Microbial lectins as a potential therapeutics for the prevention of certain human diseases. Life Sci 2024; 346:122643. [PMID: 38614308 DOI: 10.1016/j.lfs.2024.122643] [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: 02/09/2024] [Revised: 03/20/2024] [Accepted: 04/10/2024] [Indexed: 04/15/2024]
Abstract
Lectins are protein or glycoprotein molecules with a specific ability to bind to carbohydrates. From viruses to mammals, they are found in various organisms and exhibit remarkable diverse structures and functions. They are significant contributors to defense mechanisms against microbial attacks in plants. They are also involved in functions such as controlling lymphocyte migration, regulating glycoprotein biosynthesis, cell-cell recognition, and embryonic development in animals. In addition, lectins serve as invaluable molecular tools in various biological and medical disciplines due to their reversible binding ability and enable the monitoring of cell membrane changes in physiological and pathological contexts. Microbial lectins, often referred to as adhesins, play an important role in microbial colonization, pathogenicity, and interactions among microorganisms. Viral lectins are located in the bilayered viral membrane, whereas bacterial lectins are found intracellularly and on the bacterial cell surface. Microfungal lectins are typically intracellular and have various functions in host-parasite interaction, and in fungal growth and morphogenesis. Although microbial lectin studies are less extensive than those of plants and animals, they provide insights into the infection mechanisms and potential interventions. Glycan specificity, essential functions in infectious diseases, and applications in the diagnosis and treatment of viral and bacterial infections are critical aspects of microbial lectin research. In this review, we will discuss the application and therapeutic potential of viral, bacterial and microfungal lectins.
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Affiliation(s)
- Suna Bektas
- Institute of Graduate Studies in Sciences, Istanbul University, Istanbul 34116, Turkey.
| | - Engin Kaptan
- Istanbul University, Faculty of Science Department of Biology, 34134 Vezneciler, Istanbul, Turkey.
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2
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Maier I, Kontaxis G, Zimmermann C, Steininger C. Cyanovirin-N Binding to N-Acetyl-d-glucosamine Requires Carbohydrate-Binding Sites on Two Different Protomers. Biochemistry 2024; 63:1270-1277. [PMID: 38770609 PMCID: PMC11112747 DOI: 10.1021/acs.biochem.4c00113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/30/2024] [Accepted: 04/01/2024] [Indexed: 05/22/2024]
Abstract
Cyanovirin-N (CV-N) binds high-mannose oligosaccharides on enveloped viruses with two carbohydrate-binding sites, one bearing high affinity and one low affinity to Manα(1-2)Man moieties. A tandem repeat of two CV-N molecules (CVN2) was tested for antiviral activity against human immunodeficiency virus type I (HIV-1) by using a domain-swapped dimer. CV-N was shown to bind N-acetylmannosamine (ManNAc) and N-acetyl-d-glucosamine (GlcNAc) when the carbohydrate-binding sites in CV-N were free to interact with these monosaccharides independently. CVN2 recognized ManNAc at a Kd of 1.4 μM and bound this sugar in solution, regardless of the lectin making amino acid side chain contacts on the targeted viral glycoproteins. An interdomain cross-contacting residue Glu41, which has been shown to be hydrogen bonding with dimannose, was substituted in the monomeric CV-N. The amide derivative of glucose, GlcNAc, achieved similar high affinity to the new variant CVN-E41T as high-mannose N-glycans, but binding to CVN2 in the nanomolar range with four binding sites involved or binding to the monomeric CVN-E41A. A stable dimer was engineered and expressed from the alanine-to-threonine-substituted monomer to confirm binding to GlcNAc. In summary, low-affinity binding was achieved by CVN2 to dimannosylated peptide or GlcNAc with two carbohydrate-binding sites of differing affinities, mimicking biological interactions with the respective N-linked glycans of interest and cross-linking of carbohydrates on human T cells for lymphocyte activation.
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Affiliation(s)
- Irene Maier
- Department
of Environmental Health Sciences, Fielding School of Public Health, University of California, Los Angeles, 650 Charles E. Young Dr. South, Los Angeles, California 90095, United States
- Department
of Internal Medicine I, Medical University
of Vienna, Waehringer Guertel 18-20, Vienna A-1090, Austria
| | - Georg Kontaxis
- Department
of Computational and Structural Biology, Max Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, Vienna 1030, Austria
| | - Christian Zimmermann
- Institute
of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, Wien 1060, Austria
| | - Christoph Steininger
- Department
of Internal Medicine I, Medical University
of Vienna, Waehringer Guertel 18-20, Vienna A-1090, Austria
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3
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Nazmul T, Lawal-Ayinde BM, Morita T, Yoshimoto R, Higashiura A, Yamamoto A, Nomura T, Nakano Y, Hirayama M, Kurokawa H, Kitamura Y, Hori K, Sakaguchi T. Capture and neutralization of SARS-CoV-2 and influenza virus by algae-derived lectins with high-mannose and core fucose specificities. Microbiol Immunol 2023. [PMID: 37248051 DOI: 10.1111/1348-0421.13082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 05/02/2023] [Accepted: 05/14/2023] [Indexed: 05/31/2023]
Abstract
We first investigated the interactions between several algae-derived lectins and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). We created lectin columns using high-mannose (HM)-type glycan-specific lectins OAA and KAA-1 or core fucose-specific lectin hypninA-2 and conducted binding experiments with SARS-CoV-2. The results showed that these lectins were capable of binding to the virus. Furthermore, when examining the neutralization ability of nine different lectins, it was found that KAA-1, ESA-2, and hypninA-2 were effective in neutralizing SARS-CoV-2. In competitive inhibition experiments with glycoproteins, neutralization was confirmed to occur through HM-type or core fucose-type glycans. However, neutralization was not observed with other lectins, such as OAA. This trend of KAA-1 and ESA-2 having the neutralizing ability and OAA not having it was also similar to influenza viruses. Electron microscopy observations revealed that KAA-1 and hypninA-2 strongly aggregated SARS-CoV-2 particles, while OAA showed a low degree of aggregation. It is believed that the neutralization of SARS-CoV-2 involves multiple factors, such as glycan attachment sites on the S protein, the size of lectins, and their propensity to aggregate, which cause inhibition of receptor binding or aggregation of virus particles. This study demonstrated that several algae-derived lectins could neutralize SARS-CoV-2 and that lectin columns can effectively recover and concentrate the virus.
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Affiliation(s)
- Tanuza Nazmul
- Department of Virology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Basirat M Lawal-Ayinde
- Department of Virology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Tomoko Morita
- Department of Virology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Reiko Yoshimoto
- Department of Virology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Akifumi Higashiura
- Department of Virology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Akima Yamamoto
- Department of Virology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Toshihito Nomura
- Department of Virology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
- Department of Infectious Diseases, Hiroshima University Hospital, Hiroshima, Japan
| | - Yukiko Nakano
- Laboratory of Marine Bioresource Chemistry, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Makoto Hirayama
- Laboratory of Marine Bioresource Chemistry, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | | | | | - Kanji Hori
- Laboratory of Marine Bioresource Chemistry, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Takemasa Sakaguchi
- Department of Virology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
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4
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Maier I. Engineering recombinantly expressed lectin-based antiviral agents. Front Cell Infect Microbiol 2022; 12:990875. [PMID: 36211961 PMCID: PMC9539805 DOI: 10.3389/fcimb.2022.990875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Accepted: 08/25/2022] [Indexed: 11/30/2022] Open
Abstract
Cyanovirin-N (CV-N), a lectin from Nostoc ellipsosporum was found an infusion inhibitory protein for human immunodeficiency virus (HIV)-1. A tandem-repeat of the engineered domain-swapped dimer bound specific sites at hemagglutinin (HA), Ebola and HIV spike glycoproteins as well as dimannosylated HA peptide, N-acetyl-D-glucosamine and high-mannose containing oligosaccharides. Among these, CV-N bound the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike protein at a dissociation constant (KD) of 18.6 µM (and KD=260 µM to RBD), which was low-affinity carbohydrate-binding as compared with the recognition of the other viral spikes. Binding of dimannosylated peptide to homo-dimeric CVN2 and variants of CVN2 that were pairing Glu-Arg residues sterically located close to its high-affinity carbohydrate binding sites, was measured using surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC). Binding affinity increased with polar interactions, when the mutated residues were used to substitute a single, or two disulfide bonds, in CVN2. Site-specific N-linked glycans on spikes were mediating the infection with influenza virus by broadly neutralizing antibodies to HA and lectin binding to HA was further investigated via modes of saturation transfer difference (STD)-NMR. Our findings showed that stoichiometry and the lectin’s binding affinity were revealed by an interaction of CVN2 with dimannose units and either the high- or low-affinity binding site. To understand how these binding mechanisms add to viral membrane fusion we compare our tested HA-derived peptides in affinity with SARS-CoV-2 glycoprotein and review lectins and their mechanisms of binding to enveloped viruses for a potential use to simulate neutralization ability.
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Kazan IC, Sharma P, Rahman MI, Bobkov A, Fromme R, Ghirlanda G, Ozkan SB. Design of novel cyanovirin-N variants by modulation of binding dynamics through distal mutations. eLife 2022; 11:67474. [PMID: 36472898 PMCID: PMC9725752 DOI: 10.7554/elife.67474] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 11/28/2022] [Indexed: 12/07/2022] Open
Abstract
We develop integrated co-evolution and dynamic coupling (ICDC) approach to identify, mutate, and assess distal sites to modulate function. We validate the approach first by analyzing the existing mutational fitness data of TEM-1 β-lactamase and show that allosteric positions co-evolved and dynamically coupled with the active site significantly modulate function. We further apply ICDC approach to identify positions and their mutations that can modulate binding affinity in a lectin, cyanovirin-N (CV-N), that selectively binds to dimannose, and predict binding energies of its variants through Adaptive BP-Dock. Computational and experimental analyses reveal that binding enhancing mutants identified by ICDC impact the dynamics of the binding pocket, and show that rigidification of the binding residues compensates for the entropic cost of binding. This work suggests a mechanism by which distal mutations modulate function through dynamic allostery and provides a blueprint to identify candidates for mutagenesis in order to optimize protein function.
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Affiliation(s)
- I Can Kazan
- Center for Biological Physics and Department of Physics, Arizona State UniversityTempeUnited States,School of Molecular Sciences, Arizona State UniversityTempeUnited States
| | - Prerna Sharma
- School of Molecular Sciences, Arizona State UniversityTempeUnited States
| | | | - Andrey Bobkov
- Sanford Burnham Prebys Medical Discovery InstituteLa JollaUnited States
| | - Raimund Fromme
- School of Molecular Sciences, Arizona State UniversityTempeUnited States
| | - Giovanna Ghirlanda
- School of Molecular Sciences, Arizona State UniversityTempeUnited States
| | - S Banu Ozkan
- Center for Biological Physics and Department of Physics, Arizona State UniversityTempeUnited States
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Maier I, Schiestl RH, Kontaxis G. Cyanovirin-N Binds Viral Envelope Proteins at the Low-Affinity Carbohydrate Binding Site without Direct Virus Neutralization Ability. Molecules 2021; 26:3621. [PMID: 34199200 PMCID: PMC8231982 DOI: 10.3390/molecules26123621] [Citation(s) in RCA: 7] [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: 04/27/2021] [Revised: 05/26/2021] [Accepted: 06/07/2021] [Indexed: 01/30/2023] Open
Abstract
Glycan-targeting antibodies and pseudo-antibodies have been extensively studied for their stoichiometry, avidity, and their interactions with the rapidly modifying glycan shield of influenza A. Broadly neutralizing antiviral agents bind in the same order when they neutralize enveloped viruses regardless of the location of epitopes to the host receptor binding site. Herein, we investigated the binding of cyanovirin-N (CV-N) to surface-expressed glycoproteins such as those of human immunodeficiency virus (HIV) gp120, hemagglutinin (HA), and Ebola (GP)1,2 and compared their binding affinities with the binding response to the trimer-folded gp140 using surface plasmon resonance (SPR). Binding-site knockout variants of an engineered dimeric CV-N molecule (CVN2) revealed a binding affinity that correlated with the number of (high-) affinity binding sites. Binding curves were specific for the interaction with N-linked glycans upon binding with two low-affinity carbohydrate binding sites. This biologically active assembly of a domain-swapped CVN2, or monomeric CV-N, bound to HA with a maximum KD of 2.7 nM. All three envelope spike proteins were recognized at a nanomolar KD, whereas binding to HIV neutralizing 2G12 by targeting HA and Ebola GP1,2 was measured in the µM range and specific for the bivalent binding scheme in SPR. In conclusion, invariant structural protein patterns provide a substrate for affinity maturation in the membrane-anchored HA regions, as well as the glycan shield on the membrane-distal HA top part. They can also induce high-affinity binding in antiviral CV-N to HA at two sites, and CVN2 binding is achieved at low-affinity binding sites.
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Affiliation(s)
- Irene Maier
- Department of Environmental Health Sciences, Fielding School of Public Health, University of California, Los Angeles, CA 90095, USA;
| | - Robert H. Schiestl
- Department of Environmental Health Sciences, Fielding School of Public Health, University of California, Los Angeles, CA 90095, USA;
| | - Georg Kontaxis
- Max Perutz Laboratories, Department of Structural and Computational Biology, University of Vienna, A-1030 Vienna, Austria;
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Lebreton A, Bonnardel F, Dai YC, Imberty A, Martin FM, Lisacek F. A Comprehensive Phylogenetic and Bioinformatics Survey of Lectins in the Fungal Kingdom. J Fungi (Basel) 2021; 7:453. [PMID: 34200153 PMCID: PMC8227253 DOI: 10.3390/jof7060453] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/02/2021] [Accepted: 06/03/2021] [Indexed: 12/28/2022] Open
Abstract
Fungal lectins are a large family of carbohydrate-binding proteins with no enzymatic activity. They play fundamental biological roles in the interactions of fungi with their environment and are found in many different species across the fungal kingdom. In particular, their contribution to defense against feeders has been emphasized, and when secreted, lectins may be involved in the recognition of bacteria, fungal competitors and specific host plants. Carbohydrate specificities and quaternary structures vary widely, but evidence for an evolutionary relationship within the different classes of fungal lectins is supported by a high degree of amino acid sequence identity. The UniLectin3D database contains 194 fungal lectin 3D structures, of which 129 are characterized with a carbohydrate ligand. Using the UniLectin3D lectin classification system, 109 lectin sequence motifs were defined to screen 1223 species deposited in the genomic portal MycoCosm of the Joint Genome Institute. The resulting 33,485 putative lectin sequences are organized in MycoLec, a publicly available and searchable database. These results shed light on the evolution of the lectin gene families in fungi.
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Affiliation(s)
- Annie Lebreton
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China; (A.L.); (Y.-C.D.)
| | - François Bonnardel
- University of Grenoble-Alpes, CNRS, CERMAV, 38000 Grenoble, France;
- Swiss Institute of Bioinformatics, CH-1227 Geneva, Switzerland
- Computer Science Department, UniGe, CH-1227 Geneva, Switzerland
| | - Yu-Cheng Dai
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China; (A.L.); (Y.-C.D.)
| | - Anne Imberty
- University of Grenoble-Alpes, CNRS, CERMAV, 38000 Grenoble, France;
| | - Francis M. Martin
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China; (A.L.); (Y.-C.D.)
- Université de Lorraine, INRAE, UMR Interactions Arbres/Microorganismes (IAM), Laboratoire d’Excellence ARBRE, Centre INRAE GrandEst-Nancy, 54280 Champenoux, France
| | - Frédérique Lisacek
- Swiss Institute of Bioinformatics, CH-1227 Geneva, Switzerland
- Computer Science Department, UniGe, CH-1227 Geneva, Switzerland
- Section of Biology, UniGe, CH-1205 Geneva, Switzerland
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8
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Antiviral Cyanometabolites-A Review. Biomolecules 2021; 11:biom11030474. [PMID: 33810129 PMCID: PMC8004682 DOI: 10.3390/biom11030474] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/19/2021] [Accepted: 03/20/2021] [Indexed: 12/14/2022] Open
Abstract
Global processes, such as climate change, frequent and distant travelling and population growth, increase the risk of viral infection spread. Unfortunately, the number of effective and accessible medicines for the prevention and treatment of these infections is limited. Therefore, in recent years, efforts have been intensified to develop new antiviral medicines or vaccines. In this review article, the structure and activity of the most promising antiviral cyanobacterial products are presented. The antiviral cyanometabolites are mainly active against the human immunodeficiency virus (HIV) and other enveloped viruses such as herpes simplex virus (HSV), Ebola or the influenza viruses. The majority of the metabolites are classified as lectins, monomeric or dimeric proteins with unique amino acid sequences. They all show activity at the nanomolar range but differ in carbohydrate specificity and recognize a different epitope on high mannose oligosaccharides. The cyanobacterial lectins include cyanovirin-N (CV-N), scytovirin (SVN), microvirin (MVN), Microcystisviridis lectin (MVL), and Oscillatoria agardhii agglutinin (OAA). Cyanobacterial polysaccharides, peptides, and other metabolites also have potential to be used as antiviral drugs. The sulfated polysaccharide, calcium spirulan (CA-SP), inhibited infection by enveloped viruses, stimulated the immune system’s response, and showed antitumor activity. Microginins, the linear peptides, inhibit angiotensin-converting enzyme (ACE), therefore, their use in the treatment of COVID-19 patients with injury of the ACE2 expressing organs is considered. In addition, many cyanobacterial extracts were revealed to have antiviral activities, but the active agents have not been identified. This fact provides a good basis for further studies on the therapeutic potential of these microorganisms.
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Lima ADM, Siqueira AS, Möller MLS, Souza RCD, Cruz JN, Lima ARJ, Silva RCD, Aguiar DCF, Junior JLDSGV, Gonçalves EC. In silico improvement of the cyanobacterial lectin microvirin and mannose interaction. J Biomol Struct Dyn 2020; 40:1064-1073. [PMID: 32990187 DOI: 10.1080/07391102.2020.1821782] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Lectins that bind to HIV envelope glycoprotein can inhibit virus-cell fusion and be used for rational drug design. This paper presents the results of an in silico approach to improve affinity interaction between the cyanobacterial lectin microvirin and its ligand Manα(1-2)Man. Comparative modeling and molecular dynamics tools were used. Additionally, the alanine scanning webserver was used to study the importance of protein residues in the binding site and to guide mutant production. The model obtained presented two homologous domains designated as domains A and B, each consisting of a single strand with triple and antiparallel β-sheets of (β1-β3 and β6-β8). Disulfide bonds between the cysteines (Cys60-Cys80, Cys63-Cys78 and Cys8-Cys24) were also found. The highly conserved binding site, including residues Asn44, Ile45, Asp46, Gln54, Asn55, Glu58, Thr59, Gln81, Thr82 and Met83. The RMSD values of the di-mannose and the interaction site were very stable during the molecular dynamics. Calculations of the occupation time of the hydrogen bonds were made for the residues that showed interaction in the complex lectin and ligand. The residue that contributed most to the interaction with Manα(1-2)Man was Asn55. After validation, the model generated remained stable during the entire simulation. Despite its structural similarity with the template we used, our mutant (Thr82Arg) showed a higher affinity interaction with Manα(1-2)Man. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Adonis de Melo Lima
- Laboratório de Tecnologia Biomolecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | - Andrei Santos Siqueira
- Laboratório de Tecnologia Biomolecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | - Marina Luiza Saraiva Möller
- Laboratório de Tecnologia Biomolecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | | | - Jorddy Neves Cruz
- Laboratório de Tecnologia Biomolecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | - Alex Ranieri Jerônimo Lima
- Laboratório de Tecnologia Biomolecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | - Ronaldo Correia da Silva
- Laboratório de Tecnologia Biomolecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | | | | | - Evonnildo Costa Gonçalves
- Laboratório de Tecnologia Biomolecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
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Nestor G, Ruda A, Anderson T, Oscarson S, Widmalm G, Gronenborn AM. A detailed picture of a protein-carbohydrate hydrogen-bonding network revealed by NMR and MD simulations. Glycobiology 2020; 31:508-518. [PMID: 32902635 PMCID: PMC8091458 DOI: 10.1093/glycob/cwaa081] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/10/2020] [Accepted: 08/11/2020] [Indexed: 11/12/2022] Open
Abstract
Cyanovirin-N (CV-N) is a cyanobacterial lectin with antiviral activity towards HIV and several other viruses. Here, we identify mannoside hydroxyl protons that are hydrogen bonded to the protein backbone of the CV-N domain B binding site, using NMR spectroscopy. For the two carbohydrate ligands Manα(1→2)ManαOMe and Manα(1→2) Manα(1→6)ManαOMe five hydroxyl protons are involved in hydrogen-bonding networks. Comparison with previous crystallographic results revealed that four of these hydroxyl protons donate hydrogen bonds to protein backbone carbonyl oxygens in solution and in the crystal. Hydrogen bonds were not detected between the side chains of Glu41 and Arg76 with sugar hydroxyls, as previously proposed for CV-N binding of mannosides. Molecular dynamics simulations of the CV-N/Manα(1→2)Manα(1→6)ManαOMe complex confirmed the NMR-determined hydrogen-bonding network. Detailed characterization of CV-N/mannoside complexes provides a better understanding of lectin-carbohydrate interactions and opens up to the use of CV-N and similar lectins as antiviral agents.
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Affiliation(s)
- Gustav Nestor
- Department of Structural Biology, University of Pittsburgh School of Medicine,1051 BST3, 3501 Fifth Ave, Pittsburgh, PA 15261, USA.,Department of Molecular Sciences, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07, Uppsala, Sweden
| | - Alessandro Ruda
- Department of Organic Chemistry, Stockholm University, Svante Arrhenius väg 16C, Stockholm, Sweden
| | - Taigh Anderson
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Stefan Oscarson
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Göran Widmalm
- Department of Organic Chemistry, Stockholm University, Svante Arrhenius väg 16C, Stockholm, Sweden
| | - Angela M Gronenborn
- Department of Structural Biology, University of Pittsburgh School of Medicine,1051 BST3, 3501 Fifth Ave, Pittsburgh, PA 15261, USA
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11
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Long M, Ní Cheallaigh A, Reihill M, Oscarson S, Lahmann M. Synthesis of type 1 Lewis b hexasaccharide antigen structures featuring flexible incorporation of l-[U- 13C 6]-fucose for NMR binding studies. Org Biomol Chem 2020; 18:4452-4458. [PMID: 32478348 DOI: 10.1039/d0ob00426j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
While 13C-labelled proteins are common tools in NMR studies, lack of access to 13C-labelled carbohydrate structures has restricted their use. l-Fucose is involved in a wide range of physiological and pathophysiological processes in mammalian organisms. Here, l-[U-13C6]-Fuc labelled type I Lewis b (Leb) structures have been synthesised for use in NMR binding studies with the Blood-group Antigen Binding Adhesin (BabA), a membrane-bound protein from the bacterium Helicobacter pylori. As part of this work, an efficient synthesis of a benzylated l-[U-13C6]-Fuc thioglycoside donor from l-[U-13C6]-Gal has been developed. The design and synthesis of an orthogonally protected tetrasaccharide precursor enabled controlled introduction of one or two 13C-labelled or non-labelled fucosyl residues prior to global deprotection. NMR analysis showed that it is straightforward to assign the anomeric centres as well as the H-5 positions to the individual fucosyl residues which are relevant for NMR binding studies.
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Affiliation(s)
- Mark Long
- School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK.
| | - Aisling Ní Cheallaigh
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, IE
| | - Mark Reihill
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, IE
| | - Stefan Oscarson
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, IE
| | - Martina Lahmann
- School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK.
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12
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Schilling PE, Kontaxis G, Dragosits M, Schiestl RH, Becker CFW, Maier I. Mannosylated hemagglutinin peptides bind cyanovirin-N independent of disulfide-bonds in complementary binding sites. RSC Adv 2020; 10:11079-11087. [PMID: 35495330 PMCID: PMC9050506 DOI: 10.1039/d0ra01128b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 03/10/2020] [Indexed: 01/11/2023] Open
Abstract
Cyanovirin-N (CV-N) has been shown to reveal broad neutralizing activity against human immunodeficiency virus (HIV) and to specifically bind Manα(1→2)Manα units exposed on various glycoproteins of enveloped viruses, such as influenza hemagglutinin (HA) and Ebola glycoprotein. Chemically synthesized dimannosylated HA peptides bound domain-swapped and dimeric CV-N with either four disulfide-bonds (Cys–Cys), or three Cys–Cys bonds and an intact fold of the high-affinity binding site at an equilibrium dissociation constant KD of 10 μM. Cys–Cys mutagenesis with ion-pairing amino-acids glutamic acid and arginine was calculated by in silico structure-based protein design and allowed for recognizing dimannose and dimannosylated peptide binding to low-affinity binding sites (KD ≈ 11 μM for one C58–C73 bond, and binding to dimannosylated peptide). In comparison, binding to HA was achieved based on one ion-pairing C58E–C73R substitution at KD = 275 nM, and KD = 5 μM for two C58E–C73R substitutions. We were utilizing a triazole bioisostere linkage to form the respective mannosylated-derivative on the HA peptide sequence of residues glutamine, glycine, and glutamic acid. Thus, mono- and dimannosylated peptides with N-terminal cysteine facilitated site-specific interactions with HA peptides, mimicking a naturally found N-linked glycosylation site on the HA head domain. Di-mannosylated peptides reveal mannose binding to cyanovirin-N (CV-N) low-affinity binding sites.![]()
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Affiliation(s)
- Philipp E Schilling
- Faculty of Chemistry, Institute of Biological Chemistry, University of Vienna Währinger Straße 38 A-1090 Vienna Austria
| | - Georg Kontaxis
- Department of Structural and Computational Biology, Max Perutz Laboratories, University of Vienna Campus Vienna Bohrgasse 5 A-1030 Vienna Austria
| | - Martin Dragosits
- Department of Chemistry, Division of Biochemistry, University of Natural Resources and Life Sciences Muthgasse 18 A-1190 Vienna Austria
| | - Robert H Schiestl
- Department of Pathology and Laboratory Medicine, Geffen School of Medicine, University of California Los Angeles CA-90095 USA.,Department of Environmental Health Sciences, Fielding School of Public Health, University of California, Los Angeles 650 Charles E. Young Dr. South Los Angeles CA-90095 USA +1-310-267-2578 +1-310-267-2087
| | - Christian F W Becker
- Faculty of Chemistry, Institute of Biological Chemistry, University of Vienna Währinger Straße 38 A-1090 Vienna Austria
| | - Irene Maier
- Faculty of Chemistry, Institute of Biological Chemistry, University of Vienna Währinger Straße 38 A-1090 Vienna Austria.,Department of Environmental Health Sciences, Fielding School of Public Health, University of California, Los Angeles 650 Charles E. Young Dr. South Los Angeles CA-90095 USA +1-310-267-2578 +1-310-267-2087
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13
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Zhang W, Meredith R, Pan Q, Wang X, Woods RJ, Carmichael I, Serianni AS. Use of Circular Statistics To Model αMan-(1→2)-αMan and αMan-(1→3)-α/βMan O-Glycosidic Linkage Conformation in 13C-Labeled Disaccharides and High-Mannose Oligosaccharides. Biochemistry 2019; 58:546-560. [PMID: 30605318 DOI: 10.1021/acs.biochem.8b01050] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A new experimental method, MA' AT analysis, has been applied to investigate the conformational properties of O-glycosidic linkages in several biologically important mannose-containing di- and oligosaccharides. Methyl α-d-mannopyranosyl-(1→2)-α-d-mannopyranoside (2), methyl α-d-mannopyranosyl-(1→3)-α-d-mannopyranoside (3), and methyl α-d-mannopyranosyl-(1→3)-β-d-mannopyranoside (4) were prepared with selective 13C-enrichment to enable the measurement of NMR scalar couplings across their internal O-glycosidic linkages. Density functional theory (DFT) was used to parameterize equations for JCH and JCC values in 2-4 that are sensitive to phi (ϕ) and psi (ψ). The experimental J-couplings and parameterized equations were treated using a circular statistics algorithm encoded in the MA' AT program. Conformations about ϕ and ψ treated using single-state von Mises models gave excellent fits to the ensembles of redundant J-couplings. Mean values and circular standard deviations (CSDs) for each linkage torsion angle ϕ (CSD) and ψ (CSD) in 2, -29° (25°) and 20° (22°); in 3, -36° (36°) and 8° (27°); in 4, -37° (34°) and 10° (26°); ϕ = H1'-C1'-O1'-CX and ψ = C1'-O1'-CX-HX (CX = aglycone carbon) were compared to histograms obtained from 1 μs aqueous molecular dynamics (MD) simulations and X-ray database statistical analysis. MA' AT-derived models of ψ were in very good agreement with the MD and X-ray data, but not those of ϕ, suggesting a need for force field revision. The effect of structural context on linkage conformation was also investigated in four selectively 13C-labeled homomannose tri- and tetrasaccharides using the MA' AT method. In the cases examined, context effects were found to be small.
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Affiliation(s)
| | | | | | - Xiaocong Wang
- Complex Carbohydrate Research Center , University of Georgia , Athens , Georgia 30602 United States
| | - Robert J Woods
- Complex Carbohydrate Research Center , University of Georgia , Athens , Georgia 30602 United States
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14
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Abstract
Complex carbohydrates are ubiquitous in nature, and together with proteins and nucleic acids they comprise the building blocks of life. But unlike proteins and nucleic acids, carbohydrates form nonlinear polymers, and they are not characterized by robust secondary or tertiary structures but rather by distributions of well-defined conformational states. Their molecular flexibility means that oligosaccharides are often refractory to crystallization, and nuclear magnetic resonance (NMR) spectroscopy augmented by molecular dynamics (MD) simulation is the leading method for their characterization in solution. The biological importance of carbohydrate-protein interactions, in organismal development as well as in disease, places urgency on the creation of innovative experimental and theoretical methods that can predict the specificity of such interactions and quantify their strengths. Additionally, the emerging realization that protein glycosylation impacts protein function and immunogenicity places the ability to define the mechanisms by which glycosylation impacts these features at the forefront of carbohydrate modeling. This review will discuss the relevant theoretical approaches to studying the three-dimensional structures of this fascinating class of molecules and interactions, with reference to the relevant experimental data and techniques that are key for validation of the theoretical predictions.
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Affiliation(s)
- Robert J Woods
- Complex Carbohydrate Research Center and Department of Biochemistry and Molecular Biology , University of Georgia , 315 Riverbend Road , Athens , Georgia 30602 , United States
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15
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Qadir A, Riaz M, Saeed M, Shahzad-Ul-Hussan S. Potential targets for therapeutic intervention and structure based vaccine design against Zika virus. Eur J Med Chem 2018; 156:444-460. [PMID: 30015077 DOI: 10.1016/j.ejmech.2018.07.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 06/28/2018] [Accepted: 07/06/2018] [Indexed: 01/01/2023]
Abstract
Continuously increasing number of reports of Zika virus (ZIKV) infections and associated severe clinical manifestations, including autoimmune abnormalities and neurological disorders such as neonatal microcephaly and Guillain-Barré syndrome have created alarming situation in various countries. To date, no specific antiviral therapy or vaccine is available against ZIKV. This review provides a comprehensive insight into the potential therapeutic targets and describes viral epitopes of broadly neutralizing antibodies (bNAbs) in vaccine design perspective. Interactions between ZIKV envelope glycoprotein E and cellular receptors mediate the viral fusion and entry to the target cell. Blocking these interactions by targeting cellular receptors or viral structural proteins mediating these interactions or viral surface glycans can inhibit viral entry to the cell. Similarly, different non-structural proteins of ZIKV and un-translated regions (UTRs) of its RNA play essential roles in viral replication cycle and potentiate for therapeutic interventions. Structure based vaccine design requires identity and structural description of the epitopes of bNAbs. We have described different conserved bNAb epitopes present in the ZIKV envelope as potential targets for structure based vaccine design. This review also highlights successes, unanswered questions and future perspectives in relation to therapeutic and vaccine development against ZIKV.
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Affiliation(s)
- Amina Qadir
- Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, 54792, Pakistan
| | - Muhammad Riaz
- Department of Chemistry, University of Azad Jammu & Kashmir, Muzaffarabad, Pakistan
| | - Muhammad Saeed
- Department of Chemistry and Chemical Engineering, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, 54792, Pakistan.
| | - Syed Shahzad-Ul-Hussan
- Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, 54792, Pakistan.
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16
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Lotfi H, Sheervalilou R, Zarghami N. An update of the recombinant protein expression systems of Cyanovirin-N and challenges of preclinical development. BIOIMPACTS : BI 2018. [PMID: 29977835 DOI: 10.1517/bi.2018.16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Abstract
Introduction: Human immunodeficiency virus (HIV) is a debilitating challenge and concern worldwide. Accessibility to highly active antiretroviral drugs is little or none for developing countries. Production of cost-effective microbicides to prevent the infection with HIV is a requirement. Cyanovirin-N (CVN) is known as a promising cyanobacterial lectin, capable of inhibiting the HIV cell entry in a highly specific manner. Methods: This review article presents an overview of attempts conducted on different expression systems for the recombinant production of CVN. We have also assessed the potential of the final recombinant product, as an effective anti-HIV microbicide, comparing prokaryotic and eukaryotic expression systems. Results: Artificial production of CVN is a challenging task because the desirable anti-HIV activity (CVN-gp120 interaction) depends on the correct formation of disulfide bonds during recombinant production. Thus, inexpensive and functional production of rCVN requires an effective expression system which must be found among the bacteria, yeast, and transgenic plants, for the subsequent satisfying medical application. Moreover, the strong anti-HIV potential of CVN in trace concentrations (micromolar to picomolar) was reported for the in vitro and in vivo tests. Conclusion: To produce pharmaceutically effective CVN, we first need to identify the best expression system, with Escherichia coli, Pichia pastoris , Lactic acid bacteria and transgenic plants being possible candidates. For this reason, heterologous production of this valuable protein is a serious challenge. Since different obstacles influence clinical trials on microbicides in the field of HIV prevention, these items should be considered for evaluating the CVN activity in pre-clinical and clinical studies.
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Affiliation(s)
- Hajie Lotfi
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Roghayeh Sheervalilou
- Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Nosratollah Zarghami
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
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17
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Lotfi H, Sheervalilou R, Zarghami N. An update of the recombinant protein expression systems of Cyanovirin-N and challenges of preclinical development. ACTA ACUST UNITED AC 2017; 8:139-151. [PMID: 29977835 PMCID: PMC6026528 DOI: 10.15171/bi.2018.16] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 11/05/2017] [Accepted: 11/07/2017] [Indexed: 12/15/2022]
Abstract
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Introduction: Human immunodeficiency virus (HIV) is a debilitating challenge and concern worldwide. Accessibility to highly active antiretroviral drugs is little or none for developing countries. Production of cost-effective microbicides to prevent the infection with HIV is a requirement. Cyanovirin-N (CVN) is known as a promising cyanobacterial lectin, capable of inhibiting the HIV cell entry in a highly specific manner.
Methods: This review article presents an overview of attempts conducted on different expression systems for the recombinant production of CVN. We have also assessed the potential of the final recombinant product, as an effective anti-HIV microbicide, comparing prokaryotic and eukaryotic expression systems.
Results: Artificial production of CVN is a challenging task because the desirable anti-HIV activity (CVN-gp120 interaction) depends on the correct formation of disulfide bonds during recombinant production. Thus, inexpensive and functional production of rCVN requires an effective expression system which must be found among the bacteria, yeast, and transgenic plants, for the subsequent satisfying medical application. Moreover, the strong anti-HIV potential of CVN in trace concentrations (micromolar to picomolar) was reported for the in vitro and in vivo tests.
Conclusion: To produce pharmaceutically effective CVN, we first need to identify the best expression system, with Escherichia coli, Pichia pastoris , Lactic acid bacteria and transgenic plants being possible candidates. For this reason, heterologous production of this valuable protein is a serious challenge. Since different obstacles influence clinical trials on microbicides in the field of HIV prevention, these items should be considered for evaluating the CVN activity in pre-clinical and clinical studies.
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Affiliation(s)
- Hajie Lotfi
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Roghayeh Sheervalilou
- Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Nosratollah Zarghami
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
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18
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Lusvarghi S, Ghirlando R, Davison JR, Bewley CA. Chemical and Biophysical Approaches for Complete Characterization of Lectin-Carbohydrate Interactions. Methods Enzymol 2017; 598:3-35. [PMID: 29306440 PMCID: PMC6141027 DOI: 10.1016/bs.mie.2017.06.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Lectins are carbohydrate-binding proteins unrelated to antibodies or enzymes. While carbohydrates are present on all cells and pathogens, lectins are also ubiquitous in nature and their interactions with glycans mediate countless biological and physical interactions. Due to the multivalency found in both lectins and their glycan-binding partners, complete characterization of these interactions can be complex and typically requires the use of multiple complimentary techniques. In this chapter, we provide a general strategy and protocols for chemical and biophysical approaches that can be used to characterize carbohydrate-mediated interactions in the context of individual oligosaccharides, as part of a glycoprotein, and ending with visualization of interactions with whole virions.
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Affiliation(s)
- Sabrina Lusvarghi
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Jack R Davison
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Carole A Bewley
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States.
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19
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Effects of microvirin monomers and oligomers on hepatitis C virus. Biosci Rep 2017; 37:BSR20170015. [PMID: 28507200 PMCID: PMC6434159 DOI: 10.1042/bsr20170015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 05/02/2017] [Accepted: 05/10/2017] [Indexed: 12/25/2022] Open
Abstract
Microvirin (MVN) is a carbohydrate-binding protein which shows high specificity for high-mannose type N-glycan structures. In the present study, we tried to identify whether MVN could bind to high-mannose containing hepatitis C virus (HCV) envelope glycoproteins, which are heavily decorated high-mannose glycans. In addition, recombinantly expressed MVN oligomers in di-, tri- and tetrameric form were evaluated for their viral inhibition. MVN oligomers bound more efficiently to HCV virions, and displayed in comparison with the MVN monomer a higher neutralization potency against HCV infection. The antiviral effect was furthermore affected by the peptide linker sequence connecting the MVN monomers. The results indicate that MVN oligomers such as trimers and tetramers may be used as future neutralization agents against HCV infections.
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20
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Mitchell CA, Ramessar K, O'Keefe BR. Antiviral lectins: Selective inhibitors of viral entry. Antiviral Res 2017; 142:37-54. [PMID: 28322922 PMCID: PMC5414728 DOI: 10.1016/j.antiviral.2017.03.007] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/13/2017] [Indexed: 01/27/2023]
Abstract
Many natural lectins have been reported to have antiviral activity. As some of these have been put forward as potential development candidates for preventing or treating viral infections, we have set out in this review to survey the literature on antiviral lectins. The review groups lectins by structural class and class of source organism we also detail their carbohydrate specificity and their reported antiviral activities. The review concludes with a brief discussion of several of the pertinent hurdles that heterologous proteins must clear to be useful clinical candidates and cites examples where such studies have been reported for antiviral lectins. Though the clearest path currently being followed is the use of antiviral lectins as anti-HIV microbicides via topical mucosal administration, some investigators have also found systemic efficacy against acute infections following subcutaneous administration.
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Affiliation(s)
- Carter A Mitchell
- Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Frederick, MD, 21702-1201, USA
| | - Koreen Ramessar
- Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Frederick, MD, 21702-1201, USA
| | - Barry R O'Keefe
- Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Frederick, MD, 21702-1201, USA.
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21
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Schubert M. Insights into Carbohydrate Recognition by 3D Structure Determination of Protein–Carbohydrate Complexes Using NMR. NMR IN GLYCOSCIENCE AND GLYCOTECHNOLOGY 2017:101-122. [DOI: 10.1039/9781782623946-00101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
This chapter provides an overview of protein–carbohydrate complex structures determined with NMR spectroscopy and deposited in the Protein Data Bank (PDB). These 14 structures include protein–carbohydrate interactions ranging from nanomolar to millimolar affinities. Two complexes are discussed in detail, one representing a tightly bound complex and one a weak but specific interaction. This review illustrates that NMR spectroscopy is a competitive method for three-dimensional structure determination of protein–carbohydrate complexes, especially in the case of weak interactions. The number of biological functions in which protein–carbohydrate interactions are involved is steadily growing. Essential functions of the immune system such as the distinction between self and non-self, or the resolution of inflammation, involve critical protein–carbohydrate recognition events. It is therefore expected that by providing atomic details, NMR spectroscopy can make a significant contribution in the near future to unexplored pathways of the immune system and of many other biological processes.
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Affiliation(s)
- Mario Schubert
- Department of Molecular Biology, University of Salzburg 5020 Salzburg Austria
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22
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Singh RS, Walia AK, Khattar JS, Singh DP, Kennedy JF. Cyanobacterial lectins characteristics and their role as antiviral agents. Int J Biol Macromol 2017; 102:475-496. [PMID: 28437766 DOI: 10.1016/j.ijbiomac.2017.04.041] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/29/2017] [Accepted: 04/11/2017] [Indexed: 12/12/2022]
Abstract
Lectins are ubiquitous proteins/glycoproteins of non-immune origin that bind reversibly to carbohydrates in non-covalent and highly specific manner. These lectin-glycan interactions could be exploited for establishment of novel therapeutics, targeting the adherence stage of viruses and thus helpful in eliminating wide spread viral infections. Here the review focuses on the haemagglutination activity, carbohydrate specificity and characteristics of cyanobacterial lectins. Cyanobacterial lectins exhibiting high specificity towards mannose or complex glycans have potential role as anti-viral agents. Prospective role of cyanobacterial lectins in targeting various diseases of worldwide concern such as HIV, hepatitis, herpes, influenza and ebola viruses has been discussed extensively. The review also lays emphasis on recent studies involving structural analysis of glycan-lectin interactions which in turn influence their mechanism of action. Altogether, the promising approach of these cyanobacterial lectins provides insight into their use as antiviral agents.
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Affiliation(s)
- Ram Sarup Singh
- Carbohydrate and Protein Biotechnology Laboratory, Department of Biotechnology, Punjabi University, Patiala 147002, Punjab, India.
| | - Amandeep Kaur Walia
- Carbohydrate and Protein Biotechnology Laboratory, Department of Biotechnology, Punjabi University, Patiala 147002, Punjab, India
| | | | - Davinder Pal Singh
- Department of Botany, Punjabi University, Patiala 147 002, Punjab, India
| | - John F Kennedy
- Chembiotech Laboratories, Advanced Science & Technology Institute, Kyrewood House, Tenbury Wells, Worcestershire WR1 8SG, UK
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23
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Nestor G, Anderson T, Oscarson S, Gronenborn AM. Exploiting Uniformly 13C-Labeled Carbohydrates for Probing Carbohydrate-Protein Interactions by NMR Spectroscopy. J Am Chem Soc 2017; 139:6210-6216. [PMID: 28406013 DOI: 10.1021/jacs.7b01929] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
NMR of a uniformly 13C-labeled carbohydrate was used to elucidate the atomic details of a sugar-protein complex. The structure of the 13C-labeled Manα(1-2)Manα(1-2)ManαOMe trisaccharide ligand, when bound to cyanovirin-N (CV-N), was characterized and revealed that in the complex the glycosidic linkage torsion angles between the two reducing-end mannoses are different from the free trisaccharide. Distances within the carbohydrate were employed for conformational analysis, and NOE-based distance mapping between sugar and protein revealed that Manα(1-2)Manα(1-2)ManαOMe is bound more intimately with its two reducing-end mannoses into the domain A binding site of CV-N than with the nonreducing end unit. Taking advantage of the 13C spectral dispersion of 13C-labeled carbohydrates in isotope-filtered experiments is a versatile means for a simultaneous mapping of the binding interactions on both, the carbohydrate and the protein.
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Affiliation(s)
- Gustav Nestor
- Department of Structural Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15261, United States
| | - Taigh Anderson
- Centre for Synthesis and Chemical Biology, University College Dublin , Belfield, Dublin 4, Ireland
| | - Stefan Oscarson
- Centre for Synthesis and Chemical Biology, University College Dublin , Belfield, Dublin 4, Ireland
| | - Angela M Gronenborn
- Department of Structural Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15261, United States
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24
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Shahzad-Ul-Hussan S, Sastry M, Lemmin T, Soto C, Loesgen S, Scott DA, Davison JR, Lohith K, O'Connor R, Kwong PD, Bewley CA. Insights from NMR Spectroscopy into the Conformational Properties of Man-9 and Its Recognition by Two HIV Binding Proteins. Chembiochem 2017; 18:764-771. [PMID: 28166380 PMCID: PMC5557091 DOI: 10.1002/cbic.201600665] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Indexed: 12/12/2022]
Abstract
Man9 GlcNAc2 (Man-9) present at the surface of HIV makes up the binding sites of several HIV-neutralizing agents and the mammalian lectin DC-SIGN, which is involved in cellular immunity and trans-infections. We describe the conformational properties of Man-9 in its free state and when bound by the HIV entry-inhibitor protein microvirin (MVN), and define the minimum epitopes of both MVN and DC-SIGN by using NMR spectroscopy. To facilitate the implementation of 3D 13 C-edited spectra to deconvolute spectral overlap and to determine the solution structure of Man-9, we developed a robust expression system for the production of 13 C,15 N-labeled glycans in mammalian cells. The studies reveal that Man-9 interacts with HIV-binding proteins through distinct epitopes and adopts diverse conformations in the bound state. In combination with molecular dynamics simulations we observed receptor-bound conformations to be sampled by Man-9 in the free state, thus suggesting a conformational selection mechanism for diverse recognition.
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Affiliation(s)
- Syed Shahzad-Ul-Hussan
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, 8 Center Drive, Bethesda, MD, 20892, USA
- Structural Biology Section, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, 40 Convent Drive, Bethesda, MD, 20892, USA
- Present address: Department of Biology, SBA School of Science and Engineering, Lahore University of Management Sciences, Lahore, 54792, Pakistan
| | - Mallika Sastry
- Structural Biology Section, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, 40 Convent Drive, Bethesda, MD, 20892, USA
| | - Thomas Lemmin
- Structural Biology Section, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, 40 Convent Drive, Bethesda, MD, 20892, USA
- Structural Bioinformatics Core Section, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, 40 Convent Drive, Bethesda, MD, 20892, USA
| | - Cinque Soto
- Structural Biology Section, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, 40 Convent Drive, Bethesda, MD, 20892, USA
- Structural Bioinformatics Core Section, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, 40 Convent Drive, Bethesda, MD, 20892, USA
| | - Sandra Loesgen
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, 8 Center Drive, Bethesda, MD, 20892, USA
| | - Danielle A Scott
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, 8 Center Drive, Bethesda, MD, 20892, USA
| | - Jack R Davison
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, 8 Center Drive, Bethesda, MD, 20892, USA
| | - Katheryn Lohith
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, 8 Center Drive, Bethesda, MD, 20892, USA
| | - Robert O'Connor
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, 8 Center Drive, Bethesda, MD, 20892, USA
| | - Peter D Kwong
- Structural Biology Section, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, 40 Convent Drive, Bethesda, MD, 20892, USA
- Structural Bioinformatics Core Section, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, 40 Convent Drive, Bethesda, MD, 20892, USA
| | - Carole A Bewley
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, 8 Center Drive, Bethesda, MD, 20892, USA
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25
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Lusvarghi S, Lohith K, Morin-Leisk J, Ghirlando R, Hinshaw JE, Bewley CA. Binding Site Geometry and Subdomain Valency Control Effects of Neutralizing Lectins on HIV-1 Viral Particles. ACS Infect Dis 2016; 2:882-891. [PMID: 27669574 DOI: 10.1021/acsinfecdis.6b00139] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Carbohydrate binding proteins such as griffithsin, cyanovirin-N, and BanLec are potent HIV entry inhibitors and promising microbicides. Each binds to high-mannose glycans on the surface envelope glycoprotein gp120, yet the mechanisms by which they engage viral spikes and exhibit inhibition constants ranging from nanomolar to picomolar are not understood. To determine the structural and mechanistic basis for recognition and potency, we selected a panel of lectins possessing different valencies per subunit, oligomeric states, and relative orientations of carbohydrate binding sites to systematically probe their contributions to inhibiting viral entry. Cryo-electron micrographs and immuno gold staining of lectin-treated viral particles revealed two distinct effects-namely, viral aggregation or clustering of the HIV-1 envelope on the viral membrane-that were dictated by carbohydrate binding site geometry and valency. "Sandwich" surface plasmon resonance experiments revealed that a second binding event occurs only for those lectins that could aggregate viral particles. Furthermore, picomolar Kd values were observed for the second binding event, providing a mechanism by which picomolar IC50 values are achieved. We suggest that these binding and aggregation phenomena translate to neutralization potency.
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Affiliation(s)
- Sabrina Lusvarghi
- Laboratory of Bioorganic
Chemistry, ‡Laboratory of Cell and Molecular Biology and #Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Center Drive, Bethesda, Maryland 20892, United States
| | - Katheryn Lohith
- Laboratory of Bioorganic
Chemistry, ‡Laboratory of Cell and Molecular Biology and #Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Center Drive, Bethesda, Maryland 20892, United States
| | - Jeanne Morin-Leisk
- Laboratory of Bioorganic
Chemistry, ‡Laboratory of Cell and Molecular Biology and #Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Center Drive, Bethesda, Maryland 20892, United States
| | - Rodolfo Ghirlando
- Laboratory of Bioorganic
Chemistry, ‡Laboratory of Cell and Molecular Biology and #Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Center Drive, Bethesda, Maryland 20892, United States
| | - Jenny E. Hinshaw
- Laboratory of Bioorganic
Chemistry, ‡Laboratory of Cell and Molecular Biology and #Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Center Drive, Bethesda, Maryland 20892, United States
| | - Carole A. Bewley
- Laboratory of Bioorganic
Chemistry, ‡Laboratory of Cell and Molecular Biology and #Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Center Drive, Bethesda, Maryland 20892, United States
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26
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Woodrum BW, Maxwell J, Allen DM, Wilson J, Krumpe LRH, Bobkov AA, Hill RB, Kibler KV, O'Keefe BR, Ghirlanda G. A Designed "Nested" Dimer of Cyanovirin-N Increases Antiviral Activity. Viruses 2016; 8:v8060158. [PMID: 27275831 PMCID: PMC4926178 DOI: 10.3390/v8060158] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 05/26/2016] [Accepted: 05/30/2016] [Indexed: 12/19/2022] Open
Abstract
Cyanovirin-N (CV-N) is an antiviral lectin with potent activity against enveloped viruses, including HIV. The mechanism of action involves high affinity binding to mannose-rich glycans that decorate the surface of enveloped viruses. In the case of HIV, antiviral activity of CV-N is postulated to require multivalent interactions with envelope protein gp120, achieved through a pseudo-repeat of sequence that adopts two near-identical glycan-binding sites, and possibly involves a 3D-domain-swapped dimeric form of CV-N. Here, we present a covalent dimer of CV-N that increases the number of active glycan-binding sites, and we characterize its ability to recognize four glycans in solution. A CV-N variant was designed in which two native repeats were separated by the “nested” covalent insertion of two additional repeats of CV-N, resulting in four possible glycan-binding sites. The resulting Nested CV-N folds into a wild-type-like structure as assessed by circular dichroism and NMR spectroscopy, and displays high thermal stability with a Tm of 59 °C, identical to WT. All four glycan-binding domains encompassed by the sequence are functional as demonstrated by isothermal titration calorimetry, which revealed two sets of binding events to dimannose with dissociation constants Kd of 25 μM and 900 μM, assigned to domains B and B’ and domains A and A’ respectively. Nested CV-N displays a slight increase in activity when compared to WT CV-N in both an anti-HIV cellular assay and a fusion assay. This construct conserves the original binding specifityies of domain A and B, thus indicating correct fold of the two CV-N repeats. Thus, rational design can be used to increase multivalency in antiviral lectins in a controlled manner.
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Affiliation(s)
- Brian W Woodrum
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA.
| | - Jason Maxwell
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA.
| | - Denysia M Allen
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA.
| | - Jennifer Wilson
- Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA.
| | - Lauren R H Krumpe
- Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, MD 21702, USA.
| | - Andrey A Bobkov
- Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - R Blake Hill
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Karen V Kibler
- School of Life Sciences and The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA.
| | - Barry R O'Keefe
- Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA.
| | - Giovanna Ghirlanda
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287-1604, USA.
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27
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Bailey LD, Kalyana Sundaram RV, Li H, Duffy C, Aneja R, Rosemary Bastian A, Holmes AP, Kamanna K, Rashad AA, Chaiken I. Disulfide Sensitivity in the Env Protein Underlies Lytic Inactivation of HIV-1 by Peptide Triazole Thiols. ACS Chem Biol 2015; 10:2861-73. [PMID: 26458166 DOI: 10.1021/acschembio.5b00381] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We investigated the mode of action underlying lytic inactivation of HIV-1 virions by peptide triazole thiol (PTT), in particular the relationship between gp120 disulfides and the C-terminal cysteine-SH required for virolysis. Obligate PTT dimer obtained by PTT SH cross-linking and PTTs with serially truncated linkers between pharmacophore isoleucine-ferrocenyltriazole-proline-tryptophan and cysteine-SH were synthesized. PTT variants showed loss of lytic activity but not binding and infection inhibition upon SH blockade. A disproportionate loss of lysis activity vs binding and infection inhibition was observed upon linker truncation. Molecular docking of PTT onto gp120 argued that, with sufficient linker length, the peptide SH could approach and disrupt several alternative gp120 disulfides. Inhibition of lysis by gp120 mAb 2G12, which binds at the base of the V3 loop, as well as disulfide mutational effects, argued that PTT-induced disruption of the gp120 disulfide cluster at the base of the V3 loop is an important step in lytic inactivation of HIV-1. Further, PTT-induced lysis was enhanced after treating virus with reducing agents dithiothreitol and tris (2-carboxyethyl)phosphine. Overall, the results are consistent with the view that the binding of PTT positions the peptide SH group to interfere with conserved disulfides clustered proximal to the CD4 binding site in gp120, leading to disulfide exchange in gp120 and possibly gp41, rearrangement of the Env spike, and ultimately disruption of the viral membrane. The dependence of lysis activity on thiol-disulfide interaction may be related to intrinsic disulfide exchange susceptibility in gp120 that has been reported previously to play a role in HIV-1 cell infection.
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Affiliation(s)
- Lauren D. Bailey
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Ramalingam Venkat Kalyana Sundaram
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
- School
of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Huiyuan Li
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Caitlin Duffy
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Rachna Aneja
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | | | - Andrew P. Holmes
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Kantharaju Kamanna
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Adel A. Rashad
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Irwin Chaiken
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
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28
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Sensitivity of transmitted and founder human immunodeficiency virus type 1 envelopes to carbohydrate-binding agents griffithsin, cyanovirin-N and Galanthus nivalis agglutinin. J Gen Virol 2015; 96:3660-3666. [DOI: 10.1099/jgv.0.000299] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) transmission often results from infection by a single transmitted/founder (T/F) virus. Here, we investigated the sensitivity of T/F HIV-1 envelope glycoproteins (Envs) to microbicide candidate carbohydrate-binding agents (CBAs) griffithsin (GRFT), cyanovirin-N (CV-N) and Galanthus nivalis agglutinin (GNA), showing that T/F Envs demonstrated different sensitivity to CBAs, with IC50 values ranging from 0.006 ± 0.0003 to >10 nM for GRFT, from 0.6 ± 0.2 to 28.9 ± 2.9 nM for CV-N and from 1.3 ± 0.2 to >500 nM for GNA. We further revealed that deglycosylation at position 295 or 448 decreased the sensitivity of T/F Env to GRFT, and at 339 to both CV-N and GNA. Mutation of all the three glcyans rendered a CBA-sensitive T/F Env largely resistant to GRFT, indicating that the sensitivity of T/F Env to GRFT is mainly determined by glycans at 295, 339 and 448. Our study identified specific T/F Env residues associated with CBA sensitivity.
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Li Z, Bolia A, Maxwell JD, Bobkov AA, Ghirlanda G, Ozkan SB, Margulis CJ. A Rigid Hinge Region Is Necessary for High-Affinity Binding of Dimannose to Cyanovirin and Associated Constructs. Biochemistry 2015; 54:6951-60. [PMID: 26507789 DOI: 10.1021/acs.biochem.5b00635] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Mutations in the hinge region of cyanovirin-N (CVN) dictate its preferential oligomerization state. Constructs with the Pro51Gly mutation preferentially exist as monomers, whereas wild-type cyanovirin can form domain-swapped dimers under certain conditions. Because the hinge region is an integral part of the high-affinity binding site of CVN, we investigated whether this mutation affects the shape, flexibility, and binding affinity of domain B for dimannose. Our studies indicate that the capability of monomeric wild-type CVN to resist mechanical perturbations is enhanced when compared to that of constructs in which the hinge region is more flexible. Our computational results also show that enhanced flexibility leads to blocking of the binding site by allowing different rotational isomeric states of Asn53. Moreover, at higher temperatures, this observed flexibility leads to an interaction between Asn53 and Asn42, further hindering access to the binding site. On the basis of these results, we predicted that binding affinity for dimannose would be more favorable for cyanovirin constructs containing a wild-type hinge region, whereas affinity would be impaired in the case of mutants containing Pro51Gly. Experimental characterization by isothermal titration calorimetry of a set of cyanovirin mutants confirms this hypothesis. Those possessing the Pro51Gly mutation are consistently inferior binders.
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Affiliation(s)
- Zhen Li
- Department of Chemistry, University of Iowa , Iowa City, Iowa 52242, United States
| | - Ashini Bolia
- Department of Chemistry and Biochemistry, Arizona State University , Tempe, Arizona 85287-1604, United States
| | - Jason D Maxwell
- Department of Chemistry and Biochemistry, Arizona State University , Tempe, Arizona 85287-1604, United States
| | - Andrey A Bobkov
- Sanford Burnham Medical Research Institute , 10901 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Giovanna Ghirlanda
- Department of Chemistry and Biochemistry, Arizona State University , Tempe, Arizona 85287-1604, United States
| | - S Banu Ozkan
- Center for Biological Physics, Department of Physics, Arizona State University , Tempe, Arizona 85287, United States
| | - Claudio J Margulis
- Department of Chemistry, University of Iowa , Iowa City, Iowa 52242, United States
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Acharya P, Lusvarghi S, Bewley CA, Kwong PD. HIV-1 gp120 as a therapeutic target: navigating a moving labyrinth. Expert Opin Ther Targets 2015; 19:765-83. [PMID: 25724219 DOI: 10.1517/14728222.2015.1010513] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
INTRODUCTION The HIV-1 gp120 envelope (Env) glycoprotein mediates attachment of virus to human target cells that display requisite receptors, CD4 and co-receptor, generally CCR5. Despite high-affinity interactions with host receptors and proof-of-principle by the drug maraviroc that interference with CCR5 provides therapeutic benefit, no licensed drug currently targets gp120. AREAS COVERED An overview of the role of gp120 in HIV-1 entry and of sites of potential gp120 vulnerability to therapeutic inhibition is presented. Viral defenses that protect these sites and turn gp120 into a moving labyrinth are discussed together with strategies for circumventing these defenses to allow therapeutic targeting of gp120 sites of vulnerability. EXPERT OPINION The gp120 envelope glycoprotein interacts with host proteins through multiple interfaces and has conserved structural features at these interaction sites. In spite of this, targeting gp120 for therapeutic purposes is challenging. Env mechanisms that have evolved to evade the humoral immune response also shield it from potential therapeutics. Nevertheless, substantial progress has been made in understanding HIV-1 gp120 structure and its interactions with host receptors, and in developing therapeutic leads that potently neutralize diverse HIV-1 strains. Synergies between advances in understanding, needs for therapeutics against novel viral targets and characteristics of breadth and potency for a number of gp120-targetting lead molecules bodes well for gp120 as a HIV-1 therapeutic target.
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Affiliation(s)
- Priyamvada Acharya
- National Institute of Allergy and Infectious Diseases/National Institutes of Health, Vaccine Research Center, Structural Biology Section , Room 4609B, 40 Convent Drive, Bethesda, MD 20892 , USA
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31
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Bolia A, Woodrum BW, Cereda A, Ruben MA, Wang X, Ozkan SB, Ghirlanda G. A flexible docking scheme efficiently captures the energetics of glycan-cyanovirin binding. Biophys J 2014; 106:1142-51. [PMID: 24606938 DOI: 10.1016/j.bpj.2014.01.040] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 01/08/2014] [Accepted: 01/10/2014] [Indexed: 01/10/2023] Open
Abstract
Cyanovirin-N (CVN), a cyanobacterial lectin, exemplifies a class of antiviral agents that inhibit HIV by binding to the highly glycosylated envelope protein gp120. Here, we investigate the energetics of glycan recognition using a computationally inexpensive flexible docking approach, backbone perturbation docking (BP-Dock). We benchmarked our method using two mutants of CVN: P51G-m4-CVN, which binds dimannose with high affinity through domain B, and CVN((mutDB)), in which binding to domain B has been abolished through mutation of five polar residues to small nonpolar side chains. We investigated the energetic contribution of these polar residues along with the additional position 53 by docking dimannose to single-point CVN mutant models. Analysis of the docking simulations indicated that the E41A/G and T57A mutations led to a significant decrease in binding energy scores due to rearrangements of the hydrogen-bond network that reverberated throughout the binding cavity. N42A decreased the binding score to a level comparable to that of CVN((mutDB)) by affecting the integrity of the local protein structure. In contrast, N53S resulted in a high binding energy score, similar to P51G-m4-CVN. Experimental characterization of the five mutants by NMR spectroscopy confirmed the binding affinity pattern predicted by BP-Dock. Despite their mostly conserved fold and stability, E41A, E41G, and T57A displayed dissociation constants in the millimolar range. N53S showed a binding constant in the low micromolar range, similar to that observed for P51G-m4-CVN. No binding was observed for N42A. Our results show that BP-Dock is a useful tool for rapidly screening the relative binding affinity pattern of in silico-designed mutants compared with wild-type, supporting its use to design novel mutants with enhanced binding properties.
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Affiliation(s)
- Ashini Bolia
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona
| | - Brian W Woodrum
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona
| | - Angelo Cereda
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona
| | - Melissa A Ruben
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona
| | - Xu Wang
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona
| | - S Banu Ozkan
- Center for Biological Physics, Department of Physics, Arizona State University, Tempe, Arizona.
| | - Giovanna Ghirlanda
- Center for Biological Physics, Department of Physics, Arizona State University, Tempe, Arizona.
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32
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Göbl C, Madl T, Simon B, Sattler M. NMR approaches for structural analysis of multidomain proteins and complexes in solution. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2014; 80:26-63. [PMID: 24924266 DOI: 10.1016/j.pnmrs.2014.05.003] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 05/14/2014] [Indexed: 05/22/2023]
Abstract
NMR spectroscopy is a key method for studying the structure and dynamics of (large) multidomain proteins and complexes in solution. It plays a unique role in integrated structural biology approaches as especially information about conformational dynamics can be readily obtained at residue resolution. Here, we review NMR techniques for such studies focusing on state-of-the-art tools and practical aspects. An efficient approach for determining the quaternary structure of multidomain complexes starts from the structures of individual domains or subunits. The arrangement of the domains/subunits within the complex is then defined based on NMR measurements that provide information about the domain interfaces combined with (long-range) distance and orientational restraints. Aspects discussed include sample preparation, specific isotope labeling and spin labeling; determination of binding interfaces and domain/subunit arrangements from chemical shift perturbations (CSP), nuclear Overhauser effects (NOEs), isotope editing/filtering, cross-saturation, and differential line broadening; and based on paramagnetic relaxation enhancements (PRE) using covalent and soluble spin labels. Finally, the utility of complementary methods such as small-angle X-ray or neutron scattering (SAXS, SANS), electron paramagnetic resonance (EPR) or fluorescence spectroscopy techniques is discussed. The applications of NMR techniques are illustrated with studies of challenging (high molecular weight) protein complexes.
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Affiliation(s)
- Christoph Göbl
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technische Universität München, Garching, Germany
| | - Tobias Madl
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technische Universität München, Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany; Institute of Molecular Biology, University of Graz, Graz, Austria.
| | - Bernd Simon
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Michael Sattler
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technische Universität München, Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany.
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33
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Férir G, Huskens D, Noppen S, Koharudin LMI, Gronenborn AM, Schols D. Broad anti-HIV activity of the Oscillatoria agardhii agglutinin homologue lectin family. J Antimicrob Chemother 2014; 69:2746-58. [PMID: 24970741 DOI: 10.1093/jac/dku220] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVES Oscillatoria agardhii agglutinin homologue (OAAH) proteins belong to a recently discovered lectin family. The founding member OAA and a designed hybrid OAAH (OPA) recognize similar but unique carbohydrate structures of Man-9, compared with other antiviral carbohydrate-binding agents (CBAs). These two newly described CBAs were evaluated for their inactivating properties on HIV replication and transmission and for their potential as microbicides. METHODS Various cellular assays were used to determine antiviral activity against wild-type and certain CBA-resistant HIV-1 strains: (i) free HIV virion infection in human T lymphoma cell lines and PBMCs; (ii) syncytium formation assay using persistently HIV-infected T cells and non-infected CD4+ T cells; (iii) DC-SIGN-mediated viral capture; and (iv) transmission to uninfected CD4+ T cells. OAA and OPA were also evaluated for their mitogenic properties and potential synergistic effects using other CBAs. RESULTS OAA and OPA inhibit HIV replication, syncytium formation between HIV-1-infected and uninfected T cells, DC-SIGN-mediated HIV-1 capture and transmission to CD4+ target T cells, thereby rendering a variety of HIV-1 and HIV-2 clinical isolates non-infectious, independent of their coreceptor use. Both CBAs competitively inhibit the binding of the Manα(1-2)Man-specific 2G12 monoclonal antibody (mAb) as shown by flow cytometry and surface plasmon resonance analysis. The HIV-1 NL4.3(2G12res), NL4.3(MVNres) and IIIB(GRFTres) strains were equally inhibited as the wild-type HIV-1 strains by these CBAs. Combination studies indicate that OAA and OPA act synergistically with Hippeastrum hybrid agglutinin, 2G12 mAb and griffithsin (GRFT), with the exception of OPA/GRFT. CONCLUSIONS OAA and OPA are unique CBAs with broad-spectrum anti-HIV activity; however, further optimization will be necessary for microbicidal application.
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Affiliation(s)
- Geoffrey Férir
- Rega Institute for Medical Research, University of Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium
| | - Dana Huskens
- Rega Institute for Medical Research, University of Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium
| | - Sam Noppen
- Rega Institute for Medical Research, University of Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium
| | - Leonardus M I Koharudin
- Department of Structural Biology, University of Pittsburgh School of Medicine, Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Angela M Gronenborn
- Department of Structural Biology, University of Pittsburgh School of Medicine, Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Dominique Schols
- Rega Institute for Medical Research, University of Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium
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The antiviral lectin cyanovirin-N: probing multivalency and glycan recognition through experimental and computational approaches. Biochem Soc Trans 2014; 41:1170-6. [PMID: 24059504 DOI: 10.1042/bst20130154] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
CVN (cyanovirin-N), a small lectin isolated from cyanobacteria, exemplifies a novel class of anti-HIV agents that act by binding to the highly glycosylated envelope protein gp120 (glycoprotein 120), resulting in inhibition of the crucial viral entry step. In the present review, we summarize recent work in our laboratory and others towards determining the crucial role of multivalency in the antiviral activity, and we discuss features that contribute to the high specificity and affinity for the glycan ligand observed in CVN. An integrated approach that encompasses structural determination, mutagenesis analysis and computational work holds particular promise to clarify aspects of the interactions between CVN and glycans.
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Ramadugu SK, Li Z, Kashyap HK, Margulis CJ. The role of Glu41 in the binding of dimannose to P51G-m4-CVN. Biochemistry 2014; 53:1477-84. [PMID: 24524298 DOI: 10.1021/bi4014159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The carbohydrate binding protein, Cyanovirin-N, obtained from cyanobacteria, consists of high-affinity and low-affinity binding domains. To avoid the formation of a domain swapped structure in solution and also to better focus on the binding of carbohydrates at the high-affinity site, the Ghirlanda group (Biochemistry, 46, 2007, 9199-9207) engineered the P51G-m4-CVN mutant which does not dimerize nor binds at the low-affinity site. This mutant provides an excellent starting point for the experimental and computational study of further transformations to enhance binding at the high-affinity site as well as to retool this site for the possible binding of different sugars. However, before such endeavors are pursued, detailed understanding of apparently key interactions both present in wild-type and P51G-m4-CVN at the high-affinity site must be derived and controversies about the importance of certain residues must be resolved. One such interaction is that of Glu41, a charged residue in intimate contact with 2'OH of dimannose at the nonreducing end. We do so computationally by performing two mutations using the thermodynamic integration formalism in explicit solvent. Mutations of P51G-m4-CVN Glu41 to Ala41 and Gly41 reveal that whereas the loss of Coulomb interactions result in a free energy penalty of about 2.1 kcal/mol, this is significantly compensated by favorable contributions to the Lennard-Jones portion of the transformation, resulting in almost no change in the free energy of binding. At least in terms of free energetics, and in the case of this particular CVN mutant, Glu41 does not appear to be as important as previously thought. This is not because of lack of extensive hydrogen bonding with the ligand but instead because of other compensating factors.
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Affiliation(s)
- Sai Kumar Ramadugu
- Department of Chemistry, University of Iowa , 118 IATL, Iowa City, Iowa 52241, United States
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36
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Differential inhibitory effects of cyanovirin-N, griffithsin, and scytovirin on entry mediated by envelopes of gammaretroviruses and deltaretroviruses. J Virol 2013; 88:2327-32. [PMID: 24284326 DOI: 10.1128/jvi.02553-13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The antiviral lectins griffithsin (GRFT), cyanovirin-N (CV-N), and scytovirin (SVN), which inhibit several enveloped viruses, including lentiviruses, were examined for their ability to inhibit entry mediated by Env proteins of delta- and gammaretroviruses. The glycoproteins from human T-cell leukemia virus type 1 (HTLV-1) were resistant to the antiviral effects of all three lectins. For gammaretroviruses, CV-N inhibited entry mediated by some but not all of the envelopes examined, whereas GRFT and SVN displayed only little or no effect.
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37
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Kachko A, Loesgen S, Shahzad-Ul-Hussan S, Tan W, Zubkova I, Takeda K, Wells F, Rubin S, Bewley CA, Major ME. Inhibition of hepatitis C virus by the cyanobacterial protein Microcystis viridis lectin: mechanistic differences between the high-mannose specific lectins MVL, CV-N, and GNA. Mol Pharm 2013; 10:4590-4602. [PMID: 24152340 DOI: 10.1021/mp400399b] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Plant or microbial lectins are known to exhibit potent antiviral activities against viruses with glycosylated surface proteins, yet the mechanism(s) by which these carbohydrate-binding proteins exert their antiviral activities is not fully understood. Hepatitis C virus (HCV) is known to possess glycosylated envelope proteins (gpE1E2) and to be potently inhibited by lectins. Here, we tested in detail the antiviral properties of the newly discovered Microcystis viridis lectin (MVL) along with cyanovirin-N (CV-N) and Galanthus nivalis agglutinin (GNA) against cell culture HCV, as well as their binding properties toward viral particles, target cells, and recombinant HCV glycoproteins. Using infectivity assays, CV-N, MVL, and GNA inhibited HCV with IC50 values of 0.6 nM, 30.4 nM, and 11.1 nM, respectively. Biolayer interferometry analysis demonstrated a higher affinity of GNA to immobilized recombinant HCV glycoproteins compared to CV-N and MVL. Complementary studies, including fluorescence-activated cell sorting (FACS) analysis, confocal microscopy, and pre- and post-virus binding assays, showed a complex mechanism of inhibition for CV-N and MVL that includes both viral and cell association, while GNA functions by binding directly to the viral particle. Combinations of GNA with CV-N or MVL in HCV infection studies revealed synergistic inhibitory effects, which can be explained by different glycan recognition profiles of the mainly high-mannoside specific lectins, and supports the hypothesis that these lectins inhibit through different and complex modes of action. Our findings provide important insights into the mechanisms by which lectins inhibit HCV infection. Overall, the data suggest MVL and CV-N have the potential for toxicity due to interactions with cellular proteins while GNA may be a better therapeutic agent due to specificity for the HCV gpE1E2.
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Affiliation(s)
- Alla Kachko
- Laboratory of Hepatitis Viruses, Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892 USA
| | - Sandra Loesgen
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda Maryland 20892, USA
| | - Syed Shahzad-Ul-Hussan
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda Maryland 20892, USA.,Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda Maryland 20892, USA
| | - Wendy Tan
- Laboratory of Hepatitis Viruses, Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892 USA
| | - Iryna Zubkova
- Laboratory of Hepatitis Viruses, Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892 USA
| | - Kazuyo Takeda
- Microscopy and Imaging Core Facility, Center for Biologics Evaluation and Research, US Food and Drug Administration, Bethesda, MD 20892. USA
| | - Frances Wells
- Laboratory of Hepatitis Viruses, Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892 USA
| | - Steven Rubin
- Laboratory of Method Development, Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892. USA
| | - Carole A Bewley
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda Maryland 20892, USA
| | - Marian E Major
- Laboratory of Hepatitis Viruses, Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892 USA
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Bewley CA, Shahzad-ul-Hussan S. Characterizing carbohydrate-protein interactions by nuclear magnetic resonance spectroscopy. Biopolymers 2013; 99:796-806. [PMID: 23784792 PMCID: PMC3820370 DOI: 10.1002/bip.22329] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 06/13/2013] [Indexed: 11/07/2022]
Abstract
Interactions between proteins and soluble carbohydrates and/or surface displayed glycans are central to countless recognition, attachment and signaling events in biology. The physical chemical features associated with these binding events vary considerably, depending on the biological system of interest. For example, carbohydrate-protein interactions can be stoichiometric or multivalent, the protein receptors can be monomeric or oligomeric, and the specificity of recognition can be highly stringent or rather promiscuous. Equilibrium dissociation constants for carbohydrate binding are known to vary from micromolar to millimolar, with weak interactions being far more prevalent; and individual carbohydrate-binding sites can be truly symmetrical or merely homologous, and hence, the affinities of individual sites within a single protein can vary, as can the order of binding. Several factors, including the weak affinities with which glycans bind their protein receptors, the dynamic nature of the glycans themselves, and the nonequivalent interactions among oligomeric carbohydrate receptors, have made nuclear magnetic resonance (NMR) an especially powerful tool for studying and defining carbohydrate-protein interactions. Here, we describe those NMR approaches that have proven to be the most robust in characterizing these systems, and explain what type of information can (or cannot) be obtained from each. Our goal is to provide the reader the information necessary for selecting the correct experiment or sets of experiments to characterize their carbohydrate-protein interaction of interest.
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Affiliation(s)
- Carole A Bewley
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
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Francesconi O, Nativi C, Gabrielli G, Gentili M, Palchetti M, Bonora B, Roelens S. Pyrrolic Tripodal Receptors for the Molecular Recognition of Carbohydrates: Ditopic Receptors for Dimannosides. Chemistry 2013; 19:11742-52. [DOI: 10.1002/chem.201204298] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Indexed: 11/08/2022]
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40
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Fujimoto YK, Green DF. Carbohydrate recognition by the antiviral lectin cyanovirin-N. J Am Chem Soc 2012; 134:19639-51. [PMID: 23057413 DOI: 10.1021/ja305755b] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cyanovirin-N (CVN) is a cyanobacterial lectin with potent antiviral activity and has been the focus of extensive preclinical investigation as a potential prophylactic for the prevention of the sexual transmission of the human immunodeficiency virus (HIV). Here we present a detailed analysis of carbohydrate recognition by this important protein, using a combination of computational methods, including extensive molecular dynamics simulations and molecular mechanics/Poisson-Boltzmann surface area (MM/PBSA) energetic analysis. The simulation results strongly suggest that the observed tendency of wild-type CVN to form domain-swapped dimers is the result of a previously unidentified cis-peptide bond present in the monomeric state. The energetic analysis additionally indicates that the highest-affinity ligand for CVN characterized to date (α-Man-(1,2)-α-Man-(1,2)-α-Man) is recognized asymmetrically by the two binding sites. Finally, we are able to provide a detailed map of the role of all binding site functional groups (both backbone and side chain) to various aspects of molecular recognition: general affinity for cognate ligands, specificity for distinct oligosaccharide targets, and the asymmetric recognition of α-Man-(1,2)-α-Man-(1,2)-α-Man. Taken as a whole, these results complement past experimental characterization (both structural and thermodynamic) to provide the most complete understanding of carbohydrate recognition by CVN to date. The results also provide strong support for the application of similar approaches to the understanding of other protein-carbohydrate complexes.
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Affiliation(s)
- Yukiji K Fujimoto
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3600, United States
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41
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Carrero P, Ardá A, Alvarez M, Doyagüez EG, Rivero-Buceta E, Quesada E, Prieto A, Solís D, Camarasa MJ, Peréz-Pérez MJ, Jiménez-Barbero J, San-Félix A. Differential Recognition of Mannose-Based Polysaccharides by Tripodal Receptors Based on a Triethylbenzene Scaffold Substituted with Trihydroxybenzoyl Moieties. European J Org Chem 2012. [DOI: 10.1002/ejoc.201201239] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
Carbohydrate biomarkers play very important roles in a wide range of biological and pathological processes. Compounds that can specifically recognize a carbohydrate biomarker are useful for targeted delivery of imaging agents and for development of new diagnostics. Furthermore, such compounds could also be candidates for the development of therapeutic agents. A tremendous amount of active work on synthetic lectin mimics has been reported in recent years. Amongst all the synthetic lectins, boronic-acid-based lectins (boronolectins) have shown great promise. Along this line, four classes of boronolectins including peptide-, nucleic-acid-, polymer-, and small-molecule-based ones are discussed with a focus on the design principles and recent advances. We hope that by presenting the potentials of this field, this review will stimulate more research in this area.
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Driessen NN, Boshoff HI, Maaskant JJ, Gilissen SA, Vink S, van der Sar AM, Vandenbroucke-Grauls CM, Bewley CA, Appelmelk BJ, Geurtsen J. Cyanovirin-N inhibits mannose-dependent Mycobacterium-C-type lectin interactions but does not protect against murine tuberculosis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2012; 189:3585-92. [PMID: 22942435 PMCID: PMC3448799 DOI: 10.4049/jimmunol.1102408] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cyanovirin-N (CV-N) is a mannose-binding lectin that inhibits HIV-1 infection by blocking mannose-dependent target cell entry via C-type lectins. Like HIV-1, Mycobacterium tuberculosis expresses mannosylated surface structures and exploits C-type lectins to gain cell access. In this study, we investigated whether CV-N, like HIV-1, can inhibit M. tuberculosis infection. We found that CV-N specifically interacted with mycobacteria by binding to the mannose-capped lipoglycan lipoarabinomannan. Furthermore, CV-N competed with the C-type lectins DC-SIGN and mannose receptor for ligand binding and inhibited the binding of M. tuberculosis to dendritic cells but, unexpectedly, not to macrophages. Subsequent in vivo infection experiments in a mouse model demonstrated that, despite its activity, CV-N did not inhibit or delay M. tuberculosis infection. This outcome argues against a critical role for mannose-dependent C-type lectin interactions during the initial stages of murine M. tuberculosis infection and suggests that, depending on the circumstances, M. tuberculosis can productively infect cells using different modes of entry.
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Affiliation(s)
- Nicole N. Driessen
- Department of Medical Microbiology and Infection Control, Free university medical center, 1081 BT Amsterdam, the Netherlands
| | - Helena I.M. Boshoff
- Tuberculosis Research Section, Laboratory of Clinical Infectious Diseases, National Institute for Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Janneke J. Maaskant
- Department of Medical Microbiology and Infection Control, Free university medical center, 1081 BT Amsterdam, the Netherlands
| | - Sebastiaan A.C. Gilissen
- Department of Medical Microbiology and Infection Control, Free university medical center, 1081 BT Amsterdam, the Netherlands
| | - Simone Vink
- Department of Medical Microbiology and Infection Control, Free university medical center, 1081 BT Amsterdam, the Netherlands
| | - Astrid M. van der Sar
- Department of Medical Microbiology and Infection Control, Free university medical center, 1081 BT Amsterdam, the Netherlands
| | | | - Carole A. Bewley
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Ben J. Appelmelk
- Department of Medical Microbiology and Infection Control, Free university medical center, 1081 BT Amsterdam, the Netherlands
| | - Jeroen Geurtsen
- Department of Medical Microbiology and Infection Control, Free university medical center, 1081 BT Amsterdam, the Netherlands
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Koharudin LMI, Gronenborn AM. Sweet entanglements--protein:glycan interactions in two HIV-inactivating lectin families. Biopolymers 2012; 99:196-202. [PMID: 23023834 DOI: 10.1002/bip.22106] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 05/25/2012] [Indexed: 11/08/2022]
Abstract
Structures and sugar binding by members of two lectin families, Cyanovirin-N homolog (CVNH) and Oscillatoria Agardhii agglutinin homolog (OAAH), were determined to elucidate the basis for recognition of high-mannose glycans on the HIV envelope glycoprotein gp120. We solved NMR solution and/or crystal structures for several lectins and delineated their carbohydrate specificity by array screening and direct NMR titrations. Both families recognize different epitopes on high-mannose glycans, namely, Manα(1-2)Man units at the end of the D1 and D3 arms and α3,α6-mannopentaose at the central branch point of Man-8 or Man-9 for CVNH and OAAH lectins, respectively.
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Affiliation(s)
- Leonardus M I Koharudin
- Department of Structural Biology, School of Medicine, University of Pittsburgh, Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA.
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45
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Xue J, Gao Y, Hoorelbeke B, Kagiampakis I, Zhao B, Demeler B, Balzarini J, Liwang PJ. The role of individual carbohydrate-binding sites in the function of the potent anti-HIV lectin griffithsin. Mol Pharm 2012; 9:2613-25. [PMID: 22827601 DOI: 10.1021/mp300194b] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Griffithsin (GRFT) is a lectin that has been shown to inhibit HIV infection by binding to high mannose glycan structures on the surface of gp120, and it is among the most potent HIV entry inhibitors reported so far. However, important biochemical details on the antiviral mechanism of GRFT action remain unexplored. In order to understand the role of the three individual carbohydrate-binding sites (CBS) in GRFT, mutations were made at each site (D30A, D70A, and D112A), and the resulting mutants were investigated. NMR studies revealed that each GRFT variant was folded but showed significant peak movement on the carbohydrate-binding face of the protein. The wild-type and each point mutant protein appeared as tight dimers with a K(d) below 4.2 μM. Mutation of any individual CBS on GRFT reduced binding of the protein to mannose, and ELISA assays revealed a partial loss of ability of each GRFT point mutant to bind gp120, with a near-complete loss of binding by the triple mutant D30A/D70A/D112A GRFT. A more quantitative surface plasmon resonance (SPR) examination showed a rather small loss of binding to gp120 for the individual GRFT point mutants (K(D): 123 to 245 pM range versus 73 pM for wild-type GRFT), but dramatic loss of the triple mutant to bind gp120 derived from R5 and X4 strains (K(D) > 12 nM). In contrast to the 2- to 3-fold loss of binding to gp120, the single CBS point mutants of GRFT were significantly less able to inhibit viral infection, exhibiting a 26- to 1900-fold loss of potency, while the triple mutant was at least 875-fold less effective against HIV-1 infection. The disparity between HIV-1 gp120 binding ability and HIV inhibitory potency for these GRFT variants indicates that gp120 binding and virus neutralization do not necessarily correlate, and suggests a mechanism that is not based on simple gp120 binding.
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Affiliation(s)
- Jie Xue
- University of California Merced, 5200 North Lake Road, Merced, California 95343, United States
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46
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Koharudin LMI, Kollipara S, Aiken C, Gronenborn AM. Structural insights into the anti-HIV activity of the Oscillatoria agardhii agglutinin homolog lectin family. J Biol Chem 2012; 287:33796-811. [PMID: 22865886 DOI: 10.1074/jbc.m112.388579] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Oscillatoria agardhii agglutinin homolog (OAAH) proteins belong to a recently discovered lectin family. All members contain a sequence repeat of ~66 amino acids, with the number of repeats varying among different family members. Apart from data for the founding member OAA, neither three-dimensional structures, information about carbohydrate binding specificities, nor antiviral activity data have been available up to now for any other members of the OAAH family. To elucidate the structural basis for the antiviral mechanism of OAAHs, we determined the crystal structures of Pseudomonas fluorescens and Myxococcus xanthus lectins. Both proteins exhibit the same fold, resembling the founding family member, OAA, with minor differences in loop conformations. Carbohydrate binding studies by NMR and x-ray structures of glycan-lectin complexes reveal that the number of sugar binding sites corresponds to the number of sequence repeats in each protein. As for OAA, tight and specific binding to α3,α6-mannopentaose was observed. All the OAAH proteins described here exhibit potent anti-HIV activity at comparable levels. Altogether, our results provide structural details of the protein-carbohydrate interaction for this novel lectin family and insights into the molecular basis of their HIV inactivation properties.
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Affiliation(s)
- Leonardus M I Koharudin
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260, USA
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47
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Algal lectins as potential HIV microbicide candidates. Mar Drugs 2012; 10:1476-1497. [PMID: 22851920 PMCID: PMC3407925 DOI: 10.3390/md10071476] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 06/22/2012] [Accepted: 06/29/2012] [Indexed: 11/23/2022] Open
Abstract
The development and use of topical microbicides potentially offers an additional strategy to reduce the spread of the Human Immunodeficiency Virus (HIV). Carbohydrate-binding agents (CBAs) that show specificity for high mannose carbohydrates on the surface of the heavily glycosylated envelope of HIV are endowed with potent anti-HIV activity. In fact, a number of algal lectins such as cyanovirin-N, microvirin, microcystis viridis lectin, scytovirin, Oscillatoria agardhii agglutinin and griffithsin are considered as potential microbicide candidates to prevent the sexual transmission of HIV through topical applications. They not only inhibit infection of cells by cell-free virus but they can also efficiently prevent virus transmission from virus-infected cells to uninfected CD4+ target T-lymphocytes and DC-SIGN-directed capture of HIV-1 and transmission to CD4+ T lymphocytes. This review focuses on the structural properties and carbohydrate specificity of these algal lectins, their antiviral activity against HIV and several other enveloped viruses, their safety profile and viral resistance patterns.
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48
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Patsalo V, Raleigh DP, Green DF. Rational and computational design of stabilized variants of cyanovirin-N that retain affinity and specificity for glycan ligands. Biochemistry 2011; 50:10698-712. [PMID: 22032696 PMCID: PMC3234137 DOI: 10.1021/bi201411c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Cyanovirin-N (CVN) is an 11 kDa pseudosymmetric cyanobacterial lectin that has been shown to inhibit infection by the human immunodeficiency virus by binding to high-mannose oligosaccharides on the surface of the viral envelope glycoprotein gp120. In this work, we describe rationally designed CVN variants that stabilize the protein fold while maintaining high affinity and selectivity for their glycan targets. Poisson-Boltzmann calculations and protein repacking algorithms were used to select stabilizing mutations in the protein core. By substituting the buried polar side chains of Ser11, Ser20, and Thr61 with aliphatic groups, we stabilized CVN by nearly 12 °C against thermal denaturation, and by 1 M GuaHCl against chemical denaturation, relative to a previously characterized stabilized mutant. Glycan microarray binding experiments confirmed that the specificity profile of carbohydrate binding is unperturbed by the mutations and is identical for all variants. In particular, the variants selectively bound glycans containing the Manα(1→2)Man linkage, which is the known minimal binding unit of CVN. We also report the slow denaturation kinetics of CVN and show that they can complicate thermodynamic analysis; in particular, the unfolding of CVN cannot be described as a fixed two-state transition. Accurate thermodynamic parameters are needed to describe the complicated free energy landscape of CVN, and we provide updated values for CVN unfolding.
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Affiliation(s)
- Vadim Patsalo
- Department of Applied Mathematics and Statistics Stony Brook University Stony Brook, New York 11794 USA
- Laufer Center for Physical and Quantitative Biology Stony Brook University Stony Brook, New York 11794 USA
| | - Daniel P. Raleigh
- Department of Chemistry Stony Brook University Stony Brook, New York 11794 USA
- Graduate Program in Biochemistry and Structural Biology Stony Brook University Stony Brook, New York 11794 USA
| | - David F. Green
- Department of Applied Mathematics and Statistics Stony Brook University Stony Brook, New York 11794 USA
- Laufer Center for Physical and Quantitative Biology Stony Brook University Stony Brook, New York 11794 USA
- Department of Chemistry Stony Brook University Stony Brook, New York 11794 USA
- Graduate Program in Biochemistry and Structural Biology Stony Brook University Stony Brook, New York 11794 USA
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Structural basis of the anti-HIV activity of the cyanobacterial Oscillatoria Agardhii agglutinin. Structure 2011; 19:1170-81. [PMID: 21827952 DOI: 10.1016/j.str.2011.05.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 05/16/2011] [Accepted: 05/22/2011] [Indexed: 11/22/2022]
Abstract
The cyanobacterial Oscillatory Agardhii agglutinin (OAA) is a recently discovered HIV-inactivating lectin that interacts with high-mannose sugars. Nuclear magnetic resonance (NMR) binding studies between OAA and α3,α6-mannopentaose (Manα(1-3)[Manα(1-3)[Manα(1-6)]Manα(1-6)]Man), the branched core unit of Man-9, revealed two binding sites at opposite ends of the protein, exhibiting essentially identical affinities. Atomic details of the specific protein-sugar contacts in the recognition loops of OAA were delineated in the high-resolution crystal structures of free and glycan-complexed protein. No major changes in the overall protein structure are induced by carbohydrate binding, with essentially identical apo- and sugar-bound conformations in binding site 1. A single peptide bond flip at W77-G78 is seen in binding site 2. Our combined NMR and crystallographic results provide structural insights into the mechanism by which OAA specifically recognizes the branched Man-9 core, distinctly different from the recognition of the D1 and D3 arms at the nonreducing end of high-mannose carbohydrates by other antiviral lectins.
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50
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Structure-function analysis of a CVNH-LysM lectin expressed during plant infection by the rice blast fungus Magnaporthe oryzae. Structure 2011; 19:662-74. [PMID: 21565701 DOI: 10.1016/j.str.2011.03.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 03/07/2011] [Accepted: 03/08/2011] [Indexed: 12/23/2022]
Abstract
The rice blast fungus Magnaporthe oryzae's genome encodes a hypothetical protein (MGG_03307) containing a type III CVNH lectin, in which a LysM domain is inserted between individual repeats of a single CVNH domain. At present, no structural or ligand binding data are available for any type III CVNH and functional studies in natural source organisms are scarce. Here, we report NMR solution structure and functional data on MGG_03307. The structure of the CVNH/LysM module revealed that intact and functionally competent CVNH and LysM domains are present. Using NMR titrations, carbohydrate specificities for both domains were determined, and it was found that each domain behaves as an isolated unit without any interdomain communication. Furthermore, live-cell imaging revealed a predominant localization of MGG_03307 within the appressorium, the specialized fungal cell for gaining entry into rice tissue. Our results suggest that MGG_03307 plays a role in the early stages of plant infection.
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