1
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Srivastava R, Panda SK, Sen Gupta PS, Chaudhary A, Naaz F, Yadav AK, Ram NK, Rana MK, Singh RK, Srivastava R. In silico evaluation of S-adenosyl-L-homocysteine analogs as inhibitors of nsp14-viral cap N7 methyltranferase and PLpro of SARS-CoV-2: synthesis, molecular docking, physicochemical data, ADMET and molecular dynamics simulations studies. J Biomol Struct Dyn 2023:1-18. [PMID: 38147408 DOI: 10.1080/07391102.2023.2297005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 12/13/2023] [Indexed: 12/28/2023]
Abstract
A series of S-adenosyl-L-homosysteine (SAH) analogs, with modification in the base and sugar moiety, have been designed, synthesized and screened as nsp14 and PLpro inhibitors of severe acute respiratory syndrome corona virus (SARS-CoV-2). The outcomes of ADMET (Adsorption, Distribution, Metabolism, Excretion, and Toxicity) studies demonstrated that the physicochemical properties of all analogs were permissible for development of these SAH analogs as antiviral agents. All molecules were screened against different SARS-CoV-2 targets using molecular docking. The docking results revealed that the SAH analogs interacted well in the active site of nsp14 protein having H-bond interactions with the amino acid residues Arg289, Val290, Asn388, Arg400, Phe401 and π-alkyl interactions with Arg289, Val290 and Phe426 of Nsp14-MTase site. These analogs also formed stable H-bonds with Leu163, Asp165, Arg167, Ser246, Gln270, Tyr274 and Asp303 residues of PLpro proteins and found to be quite stable complexes therefore behaved as probable nsp14 and PLpro inhibitors. Interestingly, analog 3 showed significant in silico activity against the nsp14 N7 methyltransferase of SARS-CoV-2. The molecular dynamics (MD) and post-MD results of analog 3 unambiguously established the higher stability of the nsp14 (N7 MTase):3 complex and also indicated its behavior as probable nsp14 inhibitor like the reference sinefungin. The docking and MD simulations studies also suggested that sinefungin did act as SARS-CoV-2 PLpro inhibitor as well. This study's findings not only underscore the efficacy of the designed SAH analogs as potent inhibitors against crucial SARS-CoV-2 proteins but also pinpoint analog 3 as a particularly promising candidate. All the study provides valuable insights, paving the way for potential advancements in antiviral drug development against SARS-CoV-2.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Ritika Srivastava
- Department of Chemical Sciences, Indian Institute of Science Education and Research Berhampur, Odisha, India
- Bioorganic Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad, India
| | - Saroj Kumar Panda
- Department of Chemical Sciences, Indian Institute of Science Education and Research Berhampur, Odisha, India
| | - Parth Sarthi Sen Gupta
- School of Biosciences and Bioengineering, D Y Patil International University, Akurdi, India
| | - Anvita Chaudhary
- Department of Applied Chemistry, Delhi Technological University, Delhi, India
| | - Farha Naaz
- Bioorganic Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad, India
| | - Aditya K Yadav
- Bioorganic Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad, India
| | - Nand Kumar Ram
- Bioorganic Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad, India
| | - Malay Kumar Rana
- Department of Chemical Sciences, Indian Institute of Science Education and Research Berhampur, Odisha, India
| | - Ramendra K Singh
- Bioorganic Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad, India
| | - Richa Srivastava
- Bioorganic Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad, India
- Department of Applied Chemistry, Delhi Technological University, Delhi, India
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2
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Panda M, Kalita E, Singh S, Kumar K, Prajapati VK. Nanobody-peptide-conjugate (NPC) for passive immunotherapy against SARS-CoV-2 variants of concern (VoC): a prospective pan-coronavirus therapeutics. Mol Divers 2023; 27:2577-2603. [PMID: 36400898 PMCID: PMC9676808 DOI: 10.1007/s11030-022-10570-x] [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: 10/06/2022] [Accepted: 11/11/2022] [Indexed: 11/19/2022]
Abstract
The COVID-19 crisis, incited by the zoonotic SARS-CoV-2 virus, has quickly escalated into a catastrophic public health issue and a grave threat to humankind owing to the advent of mutant viruses. Multiple pharmaceutical therapies or biologics envision stopping the virus from spreading further; however, WHO has voiced concerns about the variants of concern (VoCs) inability to respond. Nanobodies are a new class of antibody mimics with binding affinity and specificity similar to classical mAbs, as well as the privileges of a small molecular weight, ease of entry into solid tissues, and binding cryptic epitopes of the antigen. Herein, we investigated multiple putative anti-SARS-CoV-2 nanobodies targeting the Receptor binding domain of the WHO-listed SARS-CoV-2 variants of concern using a comprehensive computational immunoinformatics methodology. With affinity maturation via alanine scanning mutagenesis, we remodeled an ultrapotent nanobody with substantial breadth and potency, exhibiting pico-molar binding affinities against all the VoCs. An antiviral peptide with specificity for ACE-2 receptors was affixed to make it multispecific and discourage viral entry. Collectively, we constructed a broad-spectrum therapeutic biparatopic nanobody-peptide conjugate (NPC) extending coverage to SARS-CoV-2 VoCs RBDs. We PEGylated the biparatopic construct with 20kD maleimide-terminated PEG (MAL-(PEG)n-OMe) to improve its clinical efficacy limiting rapid renal clearance, and performed in silico cloning to facilitate future experimental studies. Our findings suggest that combining biparatopic nanobody conjugate with standard treatment may be a promising bivariate tool for combating viral entry during COVID-19 illness.
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Affiliation(s)
- Mamta Panda
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, Rajasthan, 305817, India
| | - Elora Kalita
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, Rajasthan, 305817, India
| | - Satyendra Singh
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, Rajasthan, 305817, India
| | - Ketan Kumar
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, Rajasthan, 305817, India
| | - Vijay Kumar Prajapati
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer, Rajasthan, 305817, India.
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3
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Krebs AS, Liu HF, Zhou Y, Rey JS, Levintov L, Shen J, Howe A, Perilla JR, Bartesaghi A, Zhang P. Molecular architecture and conservation of an immature human endogenous retrovirus. Nat Commun 2023; 14:5149. [PMID: 37620323 PMCID: PMC10449913 DOI: 10.1038/s41467-023-40786-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 08/09/2023] [Indexed: 08/26/2023] Open
Abstract
The human endogenous retrovirus K (HERV-K) is the most recently acquired endogenous retrovirus in the human genome and is activated and expressed in many cancers and amyotrophic lateral sclerosis. We present the immature HERV-K capsid structure at 3.2 Å resolution determined from native virus-like particles using cryo-electron tomography and subtomogram averaging. The structure shows a hexamer unit oligomerized through a 6-helix bundle, which is stabilized by a small molecule analogous to IP6 in immature HIV-1 capsid. The HERV-K immature lattice is assembled via highly conserved dimer and trimer interfaces, as detailed through all-atom molecular dynamics simulations and supported by mutational studies. A large conformational change mediated by the linker between the N-terminal and the C-terminal domains of CA occurs during HERV-K maturation. Comparison between HERV-K and other retroviral immature capsid structures reveals a highly conserved mechanism for the assembly and maturation of retroviruses across genera and evolutionary time.
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Affiliation(s)
- Anna-Sophia Krebs
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Hsuan-Fu Liu
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Ye Zhou
- Department of Computer Science, Duke University, Durham, NC, 27708, USA
| | - Juan S Rey
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
| | - Lev Levintov
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
| | - Juan Shen
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Andrew Howe
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Juan R Perilla
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA.
| | - Alberto Bartesaghi
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, 27710, USA.
- Department of Computer Science, Duke University, Durham, NC, 27708, USA.
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, 27708, USA.
| | - Peijun Zhang
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.
- Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford, OX3 7BN, UK.
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4
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Obr M, Percipalle M, Chernikova D, Yang H, Thader A, Pinke G, Porley D, Mansky LM, Dick RA, Schur FKM. Unconventional stabilization of the human T-cell leukemia virus type 1 immature Gag lattice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.24.548988. [PMID: 37546793 PMCID: PMC10402013 DOI: 10.1101/2023.07.24.548988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) has an atypical immature particle morphology compared to other retroviruses. This indicates that these particles are formed in a way that is unique. Here we report the results of cryo-electron tomography (cryo-ET) studies of HTLV-1 virus-like particles (VLPs) assembled in vitro, as well as derived from cells. This work shows that HTLV-1 employs an unconventional mechanism of Gag-Gag interactions to form the immature viral lattice. Analysis of high-resolution structural information from immature CA tubular arrays reveals that the primary stabilizing component in HTLV-1 is CA-NTD. Mutagenesis and biophysical analysis support this observation. This distinguishes HTLV-1 from other retroviruses, in which the stabilization is provided primarily by the CA-CTD. These results are the first to provide structural details of the quaternary arrangement of Gag for an immature deltaretrovirus, and this helps explain why HTLV-1 particles are morphologically distinct.
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Affiliation(s)
- Martin Obr
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Mathias Percipalle
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Darya Chernikova
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Huixin Yang
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA
| | - Andreas Thader
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Gergely Pinke
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Dario Porley
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Louis M Mansky
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA
| | - Robert A Dick
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Florian KM Schur
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
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5
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Highland CM, Tan A, Ricaña CL, Briggs JAG, Dick RA. Structural insights into HIV-1 polyanion-dependent capsid lattice formation revealed by single particle cryo-EM. Proc Natl Acad Sci U S A 2023; 120:e2220545120. [PMID: 37094124 PMCID: PMC10160977 DOI: 10.1073/pnas.2220545120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 03/12/2023] [Indexed: 04/26/2023] Open
Abstract
The HIV-1 capsid houses the viral genome and interacts extensively with host cell proteins throughout the viral life cycle. It is composed of capsid protein (CA), which assembles into a conical fullerene lattice composed of roughly 200 CA hexamers and 12 CA pentamers. Previous structural analyses of individual CA hexamers and pentamers have provided valuable insight into capsid structure and function, but detailed structural information about these assemblies in the broader context of the capsid lattice is lacking. In this study, we combined cryoelectron tomography and single particle analysis (SPA) cryoelectron microscopy to determine structures of continuous regions of the capsid lattice containing both hexamers and pentamers. We also developed a method of liposome scaffold-based in vitro lattice assembly ("lattice templating") that enabled us to directly study the lattice under a wider range of conditions than has previously been possible. Using this approach, we identified a critical role for inositol hexakisphosphate in pentamer formation and determined the structure of the CA lattice bound to the capsid-targeting antiretroviral drug GS-6207 (lenacapavir). Our work reveals key structural details of the mature HIV-1 CA lattice and establishes the combination of lattice templating and SPA as a robust strategy for studying retroviral capsid structure and capsid interactions with host proteins and antiviral compounds.
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Affiliation(s)
- Carolyn M. Highland
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
| | - Aaron Tan
- Structural Studies Division, Medical Research Council Laboratory of Molecular Biology, CambridgeCB2 0QH, UK
| | - Clifton L. Ricaña
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| | - John A. G. Briggs
- Structural Studies Division, Medical Research Council Laboratory of Molecular Biology, CambridgeCB2 0QH, UK
- Department of Cell and Virus Structure, Max Planck Institute of Biochemistry, Munich82512, Germany
| | - Robert A. Dick
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
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6
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Renner N, Kleinpeter A, Mallery DL, Albecka A, Rifat Faysal KM, Böcking T, Saiardi A, Freed EO, James LC. HIV-1 is dependent on its immature lattice to recruit IP6 for mature capsid assembly. Nat Struct Mol Biol 2023; 30:370-382. [PMID: 36624347 PMCID: PMC7614341 DOI: 10.1038/s41594-022-00887-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 11/03/2022] [Indexed: 01/11/2023]
Abstract
HIV-1 Gag metamorphoses inside each virion, from an immature lattice that forms during viral production to a mature capsid that drives infection. Here we show that the immature lattice is required to concentrate the cellular metabolite inositol hexakisphosphate (IP6) into virions to catalyze mature capsid assembly. Disabling the ability of HIV-1 to enrich IP6 does not prevent immature lattice formation or production of the virus. However, without sufficient IP6 molecules inside each virion, HIV-1 can no longer build a stable capsid and fails to become infectious. IP6 cannot be replaced by other inositol phosphate (IP) molecules, as substitution with other IPs profoundly slows mature assembly kinetics and results in virions with gross morphological defects. Our results demonstrate that while HIV-1 can become independent of IP6 for immature assembly, it remains dependent upon the metabolite for mature capsid formation.
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Affiliation(s)
- Nadine Renner
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK
| | - Alex Kleinpeter
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Donna L Mallery
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK
| | - Anna Albecka
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK
| | - K M Rifat Faysal
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging, School of Medical Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| | - Till Böcking
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging, School of Medical Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| | - Adolfo Saiardi
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Eric O Freed
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA.
| | - Leo C James
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK.
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7
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Pak A, Gupta M, Yeager M, Voth GA. Inositol Hexakisphosphate (IP6) Accelerates Immature HIV-1 Gag Protein Assembly toward Kinetically Trapped Morphologies. J Am Chem Soc 2022; 144:10417-10428. [PMID: 35666943 PMCID: PMC9204763 DOI: 10.1021/jacs.2c02568] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
During the late stages of the HIV-1 lifecycle, immature virions are produced by the concerted activity of Gag polyproteins, primarily mediated by the capsid (CA) and spacer peptide 1 (SP1) domains, which assemble into a spherical lattice, package viral genomic RNA, and deform the plasma membrane. Recently, inositol hexakisphosphate (IP6) has been identified as an essential assembly cofactor that efficiently produces both immature virions in vivo and immature virus-like particles in vitro. To date, however, several distinct mechanistic roles for IP6 have been proposed on the basis of independent functional, structural, and kinetic studies. In this work, we investigate the molecular influence of IP6 on the structural outcomes and dynamics of CA/SP1 assembly using coarse-grained (CG) molecular dynamics (MD) simulations and free energy calculations. Here, we derive a bottom-up, low-resolution, and implicit-solvent CG model of CA/SP1 and IP6, and simulate their assembly under conditions that emulate both in vitro and in vivo systems. Our analysis identifies IP6 as an assembly accelerant that promotes curvature generation and fissure-like defects throughout the lattice. Our findings suggest that IP6 induces kinetically trapped immature morphologies, which may be physiologically important for later stages of viral morphogenesis and potentially useful for virus-like particle technologies.
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Affiliation(s)
- Alexander
J. Pak
- Department
of Chemistry, Chicago Center for Theoretical Chemistry, Institute
for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
| | - Manish Gupta
- Department
of Chemistry, Chicago Center for Theoretical Chemistry, Institute
for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
| | - Mark Yeager
- Department
of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, United States,Center
for Membrane Biology, University of Virginia
School of Medicine, Charlottesville, Virginia 22908, United States, United States,Cardiovascular
Research Center, University of Virginia
School of Medicine, Charlottesville, Virginia 22908, United States,Department
of Medicine, Division of Cardiovascular Medicine, University of Virginia School of Medicine, Charlottesville, Virginia 22908, United States
| | - Gregory A. Voth
- Department
of Chemistry, Chicago Center for Theoretical Chemistry, Institute
for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States,E-mail:
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8
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Markússon S, Hallin EI, Bustad HJ, Raasakka A, Xu J, Muruganandam G, Loris R, Martinez A, Bramham CR, Kursula P. High-affinity anti-Arc nanobodies provide tools for structural and functional studies. PLoS One 2022; 17:e0269281. [PMID: 35671319 PMCID: PMC9173642 DOI: 10.1371/journal.pone.0269281] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 05/17/2022] [Indexed: 11/19/2022] Open
Abstract
Activity-regulated cytoskeleton-associated protein (Arc) is a multidomain protein of retroviral origin with a vital role in the regulation of synaptic plasticity and memory formation in mammals. However, the mechanistic and structural basis of Arc function is poorly understood. Arc has an N-terminal domain (NTD) involved in membrane binding and a C-terminal domain (CTD) that binds postsynaptic protein ligands. In addition, the NTD and CTD both function in Arc oligomerisation, including assembly of retrovirus-like capsids involved in intercellular signalling. To obtain new tools for studies on Arc structure and function, we produced and characterised six high-affinity anti-Arc nanobodies (Nb). The CTD of rat and human Arc were both crystallised in ternary complexes with two Nbs. One Nb bound deep into the stargazin-binding pocket of Arc CTD and suggested competitive binding with Arc ligand peptides. The crystallisation of the human Arc CTD in two different conformations, accompanied by SAXS data and molecular dynamics simulations, paints a dynamic picture of the mammalian Arc CTD. The collapsed conformation closely resembles Drosophila Arc in capsids, suggesting that we have trapped a capsid-like conformation of the human Arc CTD. Our data obtained with the help of anti-Arc Nbs suggest that structural dynamics of the CTD and dimerisation of the NTD may promote the formation of capsids. Taken together, the recombinant high-affinity anti-Arc Nbs are versatile tools that can be further developed for studying mammalian Arc structure and function, as well as mechanisms of Arc capsid formation, both in vitro and in vivo. For example, the Nbs could serve as a genetically encoded tools for inhibition of endogenous Arc interactions in the study of neuronal function and plasticity.
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Affiliation(s)
| | - Erik I. Hallin
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | | | - Arne Raasakka
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Ju Xu
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Gopinath Muruganandam
- VIB-VUB Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium
- Department of Bioengineering Sciences, Structural Biology Brussels, Vrije Universiteit Brussel, Brussel, Belgium
| | - Remy Loris
- VIB-VUB Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium
- Department of Bioengineering Sciences, Structural Biology Brussels, Vrije Universiteit Brussel, Brussel, Belgium
| | - Aurora Martinez
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | | | - Petri Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Oulu, Finland
- * E-mail:
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9
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Obr M, JH Hagen W, Dick RA, Yu L, Kotecha A, KM Schur F. Exploring high-resolution cryo-ET and subtomogram averaging capabilities of contemporary DEDs. J Struct Biol 2022; 214:107852. [DOI: 10.1016/j.jsb.2022.107852] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 03/20/2022] [Accepted: 03/23/2022] [Indexed: 01/26/2023]
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10
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Krebs AS, Mendonça LM, Zhang P. Structural Analysis of Retrovirus Assembly and Maturation. Viruses 2021; 14:54. [PMID: 35062258 PMCID: PMC8778513 DOI: 10.3390/v14010054] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/17/2021] [Accepted: 12/21/2021] [Indexed: 12/30/2022] Open
Abstract
Retroviruses have a very complex and tightly controlled life cycle which has been studied intensely for decades. After a virus enters the cell, it reverse-transcribes its genome, which is then integrated into the host genome, and subsequently all structural and regulatory proteins are transcribed and translated. The proteins, along with the viral genome, assemble into a new virion, which buds off the host cell and matures into a newly infectious virion. If any one of these steps are faulty, the virus cannot produce infectious viral progeny. Recent advances in structural and molecular techniques have made it possible to better understand this class of viruses, including details about how they regulate and coordinate the different steps of the virus life cycle. In this review we summarize the molecular analysis of the assembly and maturation steps of the life cycle by providing an overview on structural and biochemical studies to understand these processes. We also outline the differences between various retrovirus families with regards to these processes.
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Affiliation(s)
- Anna-Sophia Krebs
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (A.-S.K.); (L.M.M.)
| | - Luiza M. Mendonça
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (A.-S.K.); (L.M.M.)
| | - Peijun Zhang
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (A.-S.K.); (L.M.M.)
- Electron Bio-Imaging Centre, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
- Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford OX3 7BN, UK
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11
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Ricaña CL, Dick RA. Inositol Phosphates and Retroviral Assembly: A Cellular Perspective. Viruses 2021; 13:v13122516. [PMID: 34960784 PMCID: PMC8703376 DOI: 10.3390/v13122516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/09/2021] [Accepted: 12/11/2021] [Indexed: 12/13/2022] Open
Abstract
Understanding the molecular mechanisms of retroviral assembly has been a decades-long endeavor. With the recent discovery of inositol hexakisphosphate (IP6) acting as an assembly co-factor for human immunodeficiency virus (HIV), great strides have been made in retroviral research. In this review, the enzymatic pathways to synthesize and metabolize inositol phosphates (IPs) relevant to retroviral assembly are discussed. The functions of these enzymes and IPs are outlined in the context of the cellular biology important for retroviruses. Lastly, the recent advances in understanding the role of IPs in retroviral biology are surveyed.
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12
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Structure of a Ty1 restriction factor reveals the molecular basis of transposition copy number control. Nat Commun 2021; 12:5590. [PMID: 34552077 PMCID: PMC8458377 DOI: 10.1038/s41467-021-25849-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 09/06/2021] [Indexed: 11/30/2022] Open
Abstract
Excessive replication of Saccharomyces cerevisiae Ty1 retrotransposons is regulated by Copy Number Control, a process requiring the p22/p18 protein produced from a sub-genomic transcript initiated within Ty1 GAG. In retrotransposition, Gag performs the capsid functions required for replication and re-integration. To minimize genomic damage, p22/p18 interrupts virus-like particle function by interaction with Gag. Here, we present structural, biophysical and genetic analyses of p18m, a minimal fragment of Gag that restricts transposition. The 2.8 Å crystal structure of p18m reveals an all α-helical protein related to mammalian and insect ARC proteins. p18m retains the capacity to dimerise in solution and the crystal structures reveal two exclusive dimer interfaces. We probe our findings through biophysical analysis of interface mutants as well as Ty1 transposition and p18m restriction in vivo. Our data provide insight into Ty1 Gag structure and suggest how p22/p18 might function in restriction through a blocking-of-assembly mechanism. In Saccharomyces cerevisiae, unchecked proliferation of Ty1 retrotransposons is controlled by the process of copy number control (CNC), which requires the p22/p18 protein, translated from an internal transcript within the Ty1 GAG gene. Here, the authors present the 2.8 Å crystal structure of a minimal p18 from Ty1-Gag that is able to restrict Ty1 transposition and identify two dimer interfaces in p18, whose roles were probed by mutagenesis both in vitro and in vivo. As p22/p18 contains only one of two conserved domains required for retroelement Gag assembly, they propose that p22/p18-Gag interactions block the Ty1 virus-like particle assembly pathway, resulting in defective particles incapable of supporting retrotransposition.
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A Structural Perspective of the Role of IP6 in Immature and Mature Retroviral Assembly. Viruses 2021; 13:v13091853. [PMID: 34578434 PMCID: PMC8473085 DOI: 10.3390/v13091853] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/10/2021] [Accepted: 09/12/2021] [Indexed: 11/17/2022] Open
Abstract
The small cellular molecule inositol hexakisphosphate (IP6) has been known for ~20 years to promote the in vitro assembly of HIV-1 into immature virus-like particles. However, the molecular details underlying this effect have been determined only recently, with the identification of the IP6 binding site in the immature Gag lattice. IP6 also promotes formation of the mature capsid protein (CA) lattice via a second IP6 binding site, and enhances core stability, creating a favorable environment for reverse transcription. IP6 also enhances assembly of other retroviruses, from both the Lentivirus and the Alpharetrovirus genera. These findings suggest that IP6 may have a conserved function throughout the family Retroviridae. Here, we discuss the different steps in the viral life cycle that are influenced by IP6, and describe in detail how IP6 interacts with the immature and mature lattices of different retroviruses.
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