1
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Narkhede Y, Saxena R, Sharma T, Conarty JP, Ramirez VT, Motsa BB, Amiar S, Li S, Chapagain PP, Wiest O, Stahelin RV. Computational and experimental identification of keystone interactions in Ebola virus matrix protein VP40 dimer formation. Protein Sci 2024; 33:e4978. [PMID: 38591637 PMCID: PMC11002992 DOI: 10.1002/pro.4978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 02/01/2024] [Accepted: 03/17/2024] [Indexed: 04/10/2024]
Abstract
The Ebola virus (EBOV) is a lipid-enveloped virus with a negative sense RNA genome that can cause severe and often fatal viral hemorrhagic fever. The assembly and budding of EBOV is regulated by the matrix protein, VP40, which is a peripheral protein that associates with anionic lipids at the inner leaflet of the plasma membrane. VP40 is sufficient to form virus-like particles (VLPs) from cells, which are nearly indistinguishable from authentic virions. Due to the restrictions of studying EBOV in BSL-4 facilities, VP40 has served as a surrogate in cellular studies to examine the EBOV assembly and budding process from the host cell plasma membrane. VP40 is a dimer where inhibition of dimer formation halts budding and formation of new VLPs as well as VP40 localization to the plasma membrane inner leaflet. To better understand VP40 dimer stability and critical amino acids to VP40 dimer formation, we integrated computational approaches with experimental validation. Site saturation/alanine scanning calculation, combined with molecular mechanics-based generalized Born with Poisson-Boltzmann surface area (MM-GB/PBSA) method and molecular dynamics simulations were used to predict the energetic contribution of amino acids to VP40 dimer stability and the hydrogen bonding network across the dimer interface. These studies revealed several previously unknown interactions and critical residues predicted to impact VP40 dimer formation. In vitro and cellular studies were then pursued for a subset of VP40 mutations demonstrating reduction in dimer formation (in vitro) or plasma membrane localization (in cells). Together, the computational and experimental approaches revealed critical residues for VP40 dimer stability in an alpha-helical interface (between residues 106-117) as well as in a loop region (between residues 52-61) below this alpha-helical region. This study sheds light on the structural origins of VP40 dimer formation and may inform the design of a small molecule that can disrupt VP40 dimer stability.
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Affiliation(s)
- Yogesh Narkhede
- Department of Chemistry and BiochemistryUniversity of Notre DameNotre DameIndianaUSA
| | - Roopashi Saxena
- Borch Department of Medicinal Chemistry and Molecular Pharmacology and The Purdue Institute for Inflammation, Immunology and Infectious DiseasePurdue UniversityWest LafayetteIndianaUSA
| | - Tej Sharma
- Department of PhysicsFlorida International UniversityMiamiFloridaUSA
| | - Jacob P. Conarty
- Borch Department of Medicinal Chemistry and Molecular Pharmacology and The Purdue Institute for Inflammation, Immunology and Infectious DiseasePurdue UniversityWest LafayetteIndianaUSA
| | - Valentina Toro Ramirez
- Borch Department of Medicinal Chemistry and Molecular Pharmacology and The Purdue Institute for Inflammation, Immunology and Infectious DiseasePurdue UniversityWest LafayetteIndianaUSA
- Pharmaceutical ChemistryUniversidad CESMedellínColombia
| | - Balindile B. Motsa
- Borch Department of Medicinal Chemistry and Molecular Pharmacology and The Purdue Institute for Inflammation, Immunology and Infectious DiseasePurdue UniversityWest LafayetteIndianaUSA
| | - Souad Amiar
- Borch Department of Medicinal Chemistry and Molecular Pharmacology and The Purdue Institute for Inflammation, Immunology and Infectious DiseasePurdue UniversityWest LafayetteIndianaUSA
| | - Sheng Li
- Department of MedicineUniversity of CaliforniaSan DiegoCaliforniaUSA
| | - Prem P. Chapagain
- Department of PhysicsFlorida International UniversityMiamiFloridaUSA
- Biomolecular Sciences Institute, Florida International UniversityMiamiFloridaUSA
| | - Olaf Wiest
- Department of Chemistry and BiochemistryUniversity of Notre DameNotre DameIndianaUSA
| | - Robert V. Stahelin
- Borch Department of Medicinal Chemistry and Molecular Pharmacology and The Purdue Institute for Inflammation, Immunology and Infectious DiseasePurdue UniversityWest LafayetteIndianaUSA
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2
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Cioffi MD, Husby ML, Gerstman BS, Stahelin RV, Chapagain PP. Role of phosphatidic acid lipids on plasma membrane association of the Ebola virus matrix protein VP40. Biochim Biophys Acta Mol Cell Biol Lipids 2024; 1869:159464. [PMID: 38360201 DOI: 10.1016/j.bbalip.2024.159464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 01/14/2024] [Accepted: 01/31/2024] [Indexed: 02/17/2024]
Abstract
The Ebola virus matrix protein VP40 is responsible for the formation of the viral matrix by localizing at the inner leaflet of the human plasma membrane (PM). Various lipid types, including PI(4,5)P2 (i.e. PIP2) and phosphatidylserine (PS), play active roles in this process. Specifically, the negatively charged headgroups of both PIP2 and PS interact with the basic residues of VP40 and stabilize it at the membrane surface, allowing for eventual egress. Phosphatidic acid (PA), resulting from the enzyme phospholipase D (PLD), is also known to play an active role in viral development. In this work, we performed a biophysical and computational analysis to investigate the effects of the presence of PA on the membrane localization and association of VP40. We used coarse-grained molecular dynamics simulations to quantify VP40 hexamer interactions with the inner leaflet of the PM. Analysis of the local distribution of lipids shows enhanced lipid clustering when PA is abundant in the membrane. We observed that PA lipids have a similar role to that of PS lipids in VP40 association due to the geometry and charge. Complementary experiments performed in cell culture demonstrate competition between VP40 and a canonical PA-binding protein for the PM. Also, inhibition of PA synthesis reduced the detectable budding of virus-like particles. These computational and experimental results provide new insights into the early stages of Ebola virus budding and the role that PA lipids have on the VP40-PM association.
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Affiliation(s)
- Michael D Cioffi
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Monica L Husby
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
| | - Bernard S Gerstman
- Department of Physics, Florida International University, Miami, FL 33199, USA; Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Robert V Stahelin
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA; The Purdue Institute for Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA.
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, FL 33199, USA; Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA.
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3
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Motsa BB, Sharma T, Cioffi MD, Chapagain PP, Stahelin RV. Minor electrostatic changes robustly increase VP40 membrane binding, assembly, and budding of Ebola virus matrix protein derived virus-like particles. J Biol Chem 2024; 300:107213. [PMID: 38522519 PMCID: PMC11061732 DOI: 10.1016/j.jbc.2024.107213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 03/05/2024] [Accepted: 03/15/2024] [Indexed: 03/26/2024] Open
Abstract
Ebola virus (EBOV) is a filamentous negative-sense RNA virus, which causes severe hemorrhagic fever. There are limited vaccines or therapeutics for prevention and treatment of EBOV, so it is important to get a detailed understanding of the virus lifecycle to illuminate new drug targets. EBOV encodes for the matrix protein, VP40, which regulates assembly and budding of new virions from the inner leaflet of the host cell plasma membrane (PM). In this work, we determine the effects of VP40 mutations altering electrostatics on PM interactions and subsequent budding. VP40 mutations that modify surface electrostatics affect viral assembly and budding by altering VP40 membrane-binding capabilities. Mutations that increase VP40 net positive charge by one (e.g., Gly to Arg or Asp to Ala) increase VP40 affinity for phosphatidylserine and phosphatidylinositol 4,5-bisphosphate in the host cell PM. This increased affinity enhances PM association and budding efficiency leading to more effective formation of virus-like particles. In contrast, mutations that decrease net positive charge by one (e.g., Gly to Asp) lead to a decrease in assembly and budding because of decreased interactions with the anionic PM. Taken together, our results highlight the sensitivity of slight electrostatic changes on the VP40 surface for assembly and budding. Understanding the effects of single amino acid substitutions on viral budding and assembly will be useful for explaining changes in the infectivity and virulence of different EBOV strains, VP40 variants that occur in nature, and for long-term drug discovery endeavors aimed at EBOV assembly and budding.
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Affiliation(s)
- Balindile B Motsa
- Borch Department of Medicinal Chemistry and Molecular Pharmacology, Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana, USA
| | - Tej Sharma
- Department of Physics, Florida International University, Miami, Florida, USA
| | - Michael D Cioffi
- Department of Physics, Florida International University, Miami, Florida, USA
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, Florida, USA; Biomolecular Sciences Institute, Florida International University, Miami, Florida, USA
| | - Robert V Stahelin
- Borch Department of Medicinal Chemistry and Molecular Pharmacology, Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana, USA.
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4
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Johnson KA, Budicini MR, Bhattarai N, Sharma T, Urata S, Gerstman BS, Chapagain PP, Li S, Stahelin RV. PI(4,5)P 2 binding sites in the Ebola virus matrix protein VP40 modulate assembly and budding. J Lipid Res 2024; 65:100512. [PMID: 38295986 PMCID: PMC10909612 DOI: 10.1016/j.jlr.2024.100512] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 01/12/2024] [Accepted: 01/17/2024] [Indexed: 03/02/2024] Open
Abstract
Ebola virus (EBOV) causes severe hemorrhagic fever in humans and is lethal in a large percentage of those infected. The EBOV matrix protein viral protein 40 kDa (VP40) is a peripheral binding protein that forms a shell beneath the lipid bilayer in virions and virus-like particles (VLPs). VP40 is required for virus assembly and budding from the host cell plasma membrane. VP40 is a dimer that can rearrange into oligomers at the plasma membrane interface, but it is unclear how these structures form and how they are stabilized. We therefore investigated the ability of VP40 to form stable oligomers using in vitro and cellular assays. We characterized two lysine-rich regions in the VP40 C-terminal domain (CTD) that bind phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) and play distinct roles in lipid binding and the assembly of the EBOV matrix layer. The extensive analysis of VP40 with and without lipids by hydrogen deuterium exchange mass spectrometry revealed that VP40 oligomers become extremely stable when VP40 binds PI(4,5)P2. The PI(4,5)P2-induced stability of VP40 dimers and oligomers is a critical factor in VP40 oligomerization and release of VLPs from the plasma membrane. The two lysine-rich regions of the VP40 CTD have different roles with respect to interactions with plasma membrane phosphatidylserine (PS) and PI(4,5)P2. CTD region 1 (Lys221, Lys224, and Lys225) interacts with PI(4,5)P2 more favorably than PS and is important for VP40 extent of oligomerization. In contrast, region 2 (Lys270, Lys274, Lys275, and Lys279) mediates VP40 oligomer stability via lipid interactions and has a more prominent role in release of VLPs.
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Affiliation(s)
- Kristen A Johnson
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Melissa R Budicini
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Nisha Bhattarai
- Department of Physics, Florida International University, Miami, FL, USA
| | - Tej Sharma
- Department of Physics, Florida International University, Miami, FL, USA
| | - Sarah Urata
- Department of Medicine, University of California San Diego, San Diego, CA, USA
| | - Bernard S Gerstman
- Department of Physics, Florida International University, Miami, FL, USA; Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, FL, USA; Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Sheng Li
- Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Robert V Stahelin
- Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, IN, USA.
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5
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Motsa BB, Sharma T, Chapagain PP, Stahelin RV. Minor changes in electrostatics robustly increase VP40 membrane binding, assembly, and budding of Ebola virus matrix protein derived virus-like particles. bioRxiv 2024:2024.01.30.578092. [PMID: 38352396 PMCID: PMC10862912 DOI: 10.1101/2024.01.30.578092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
Ebola virus (EBOV) is a filamentous negative-sense RNA virus which causes severe hemorrhagic fever. There are limited vaccines or therapeutics for prevention and treatment of EBOV, so it is important to get a detailed understanding of the virus lifecycle to illuminate new drug targets. EBOV encodes for the matrix protein, VP40, which regulates assembly and budding of new virions from the inner leaflet of the host cell plasma membrane (PM). In this work we determine the effects of VP40 mutations altering electrostatics on PM interactions and subsequent budding. VP40 mutations that modify surface electrostatics affect viral assembly and budding by altering VP40 membrane binding capabilities. Mutations that increase VP40 net positive charge by one (e.g., Gly to Arg or Asp to Ala) increase VP40 affinity for phosphatidylserine (PS) and PI(4,5)P2 in the host cell PM. This increased affinity enhances PM association and budding efficiency leading to more effective formation of virus-like particles (VLPs). In contrast, mutations that decrease net positive charge by one (e.g., Gly to Asp) lead to a decrease in assembly and budding because of decreased interactions with the anionic PM. Taken together our results highlight the sensitivity of slight electrostatic changes on the VP40 surface for assembly and budding. Understanding the effects of single amino acid substitutions on viral budding and assembly will be useful for explaining changes in the infectivity and virulence of different EBOV strains, VP40 variants that occur in nature, and for long-term drug discovery endeavors aimed at EBOV assembly and budding.
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Affiliation(s)
- Balindile B. Motsa
- Borch Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
| | - Tej Sharma
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Prem P. Chapagain
- Department of Physics, Florida International University, Miami, FL 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Robert V. Stahelin
- Borch Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
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6
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Narkhede YB, Bhardwaj A, Motsa BB, Saxena R, Sharma T, Chapagain PP, Stahelin RV, Wiest O. Elucidating Residue-Level Determinants Affecting Dimerization of Ebola Virus Matrix Protein Using High-Throughput Site Saturation Mutagenesis and Biophysical Approaches. J Phys Chem B 2023; 127:6449-6461. [PMID: 37458567 DOI: 10.1021/acs.jpcb.3c01759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
The Ebola virus (EBOV) is a filamentous virus that acquires its lipid envelope from the plasma membrane of the host cell it infects. EBOV assembly and budding from the host cell plasma membrane are mediated by a peripheral protein, known as the matrix protein VP40. VP40 is a 326 amino acid protein with two domains that are loosely linked. The VP40 N-terminal domain (NTD) contains a hydrophobic α-helix, which mediates VP40 dimerization. The VP40 C-terminal domain has a cationic patch, which mediates interactions with anionic lipids and a hydrophobic region that mediates VP40 dimer-dimer interactions. The VP40 dimer is necessary for trafficking to the plasma membrane inner leaflet and interactions with anionic lipids to mediate the VP40 assembly and oligomerization. Despite significant structural information available on the VP40 dimer structure, little is known on how the VP40 dimer is stabilized and how residues outside the NTD hydrophobic portion of the α-helical dimer interface contribute to dimer stability. To better understand how VP40 dimer stability is maintained, we performed computational studies using per-residue energy decomposition and site saturation mutagenesis. These studies revealed a number of novel keystone residues for VP40 dimer stability just adjacent to the α-helical dimer interface as well as distant residues in the VP40 CTD that can stabilize the VP40 dimer form. Experimental studies with representative VP40 mutants in vitro and in cells were performed to test computational predictions that reveal residues that alter VP40 dimer stability. Taken together, these studies provide important biophysical insights into VP40 dimerization and may be useful in strategies to weaken or alter the VP40 dimer structure as a means of inhibiting the EBOV assembly.
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Affiliation(s)
- Yogesh B Narkhede
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Atul Bhardwaj
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Balindile B Motsa
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana 47907, United States
| | - Roopashi Saxena
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana 47907, United States
| | | | | | - Robert V Stahelin
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana 47907, United States
| | - Olaf Wiest
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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7
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Sharma TK, Chapagain PP, Gerstman BS, Stahelin RV. Exploring the dimer-dimer association of the ebolavirus matrix protein VP40 at the human plasma membrane. Biophys J 2023; 122:196a. [PMID: 36782941 DOI: 10.1016/j.bpj.2022.11.1194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Tej K Sharma
- Department of Physics, Florida International University, Miami, FL, USA
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, FL, USA
| | | | - Robert V Stahelin
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
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8
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Mukherjee S, Manna P, Douglas N, Chapagain PP, Jimenez R. Conformational Dynamics of mCherry Variants: A Link between Side-Chain Motions and Fluorescence Brightness. J Phys Chem B 2023; 127:52-61. [PMID: 36574626 DOI: 10.1021/acs.jpcb.2c05584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The 3-fold higher brightness of the recently developed mCherry-XL red fluorescent protein (FP) compared to its progenitor, mCherry, is due to a significant decrease in the nonradiative decay rate underlying its increased fluorescence quantum yield. To examine the structural and dynamic role of the four mutations that distinguish the two FPs and closely related variants, we employed microsecond time scale, all-atom molecular dynamics simulations. The simulations revealed that the I197R mutation leads to the formation of multiple hydrogen-bonded contacts and increased rigidity of the β-barrel. In particular, mCherryXL showed reduced nanosecond time scale breathing of the gap between the β7 and β10-strands, which was previously shown to be the most flexible region of mCherry. Together with experimental results, the simulations also reveal steric interactions of residue 161 and a network of hydrogen-bonding interactions of the chromophore with residues at positions 59, 143, and 163 that are critical in perturbing the chromophore electronic structure. Finally, we shed light on the conformational dynamics of the conserved residues R95 and S146, which are hydrogen-bonded to the chromophore, and provide physical insights into the observed photophysics. To the best of our knowledge, this is the first study that evaluates the conformational space for a set of closely related FPs generated by directed evolution.
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Affiliation(s)
- Srijit Mukherjee
- JILA, University of Colorado, Boulder and National Institute of Standards and Technology, 440 UCB, Boulder, Colorado 80309, United States.,Department of Chemistry, University of Colorado, Boulder, 215 UCB, Boulder, Colorado 80309, United States
| | - Premashis Manna
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Nancy Douglas
- Department of Chemistry, University of Colorado, Boulder, 215 UCB, Boulder, Colorado 80309, United States
| | - Prem P Chapagain
- Department of Physics, Florida International University, 11200 SW Eighth Street, CP204, Miami, Florida 33199, United States
| | - Ralph Jimenez
- JILA, University of Colorado, Boulder and National Institute of Standards and Technology, 440 UCB, Boulder, Colorado 80309, United States.,Department of Chemistry, University of Colorado, Boulder, 215 UCB, Boulder, Colorado 80309, United States
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9
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Thapa B, Adhikari NP, Tiwari PB, Chapagain PP. A 5'-Flanking C/G Pair at the Core Region Enhances the Recognition and Binding of Kaiso to Methylated DNA. J Chem Inf Model 2022; 63:2095-2103. [PMID: 36563044 DOI: 10.1021/acs.jcim.2c01294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Methyl CpG binding proteins (MBPs) are transcription factors that recognize the methylated CpG sites in DNA and mediate the DNA methylation signal into various downstream cellular processes. The C2H2 zinc finger (ZF) protein, Kaiso, also an MBP, preferentially binds to two symmetrically methylated CpG sites in DNA sequences via C-terminal C2H2 ZF domains and mediates the transcription regulation process. Investigation of the molecular mechanism of the recognition of methylated DNA (meDNA) by Kaiso is important to understand how this protein reads and translates this methylation signal into downstream transcription outcomes. Despite previous studies in Kaiso-meDNA interactions, detailed structural investigations on the sequence-specific interaction of Kaiso with the meDNA sequence are still lacking. In this work, we used molecular modeling and molecular dynamics (MD) simulation-based computational approaches to investigate the recognition of various methylated DNA sequences by Kaiso. Our MD simulation results show that the Kaiso-meDNA interaction is sequence specific. The recognition of meDNA by Kaiso is enhanced in the MeECad sequence compared to the MeCG2 sequence. Compared to the 5'-flanking T/A pair in MeCG2, both MeCG2_mutCG and MeECad sequences show that a C/G base pair allows GLU535 of Kaiso to preferably recognize and bind the core mCpG site. The core mCGmCG site is crucial for the recognition process and formation of a stable complex. Our results reveal that the 5'-flanking nucleotides are also important for the enhanced binding and recognition of methylated sites.
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Affiliation(s)
- Bidhya Thapa
- Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu 44613, Nepal.,Padma Kanya Multiple Campus, Tribhuvan University, Bagbazar, Kathmandu 44613, Nepal
| | - Narayan P Adhikari
- Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu 44613, Nepal
| | - Purushottam B Tiwari
- Department of Oncology, Georgetown University, Washington, DC 20057, United States
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, Florida 33199, United States.,Biomolecular Sciences Institute, Florida International University, Miami, Florida 33199, United States
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10
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Baral P, Pavadai E, Zhou Z, Xu Y, Tison CK, Pokhrel R, Gerstman BS, Chapagain PP. Immunoinformatic screening of Marburgvirus epitopes and computational investigations of epitope-allele complexes. Int Immunopharmacol 2022; 111:109109. [PMID: 35926269 DOI: 10.1016/j.intimp.2022.109109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/14/2022] [Accepted: 07/27/2022] [Indexed: 11/17/2022]
Abstract
Marburgvirus (MARV), a member of the Filovirus family, causes severe hemorrhagic fever in humans. Currently, there are no approved vaccines or post exposure treatment methods available against MARV. With the aim of identifying vaccine candidates against MARV, we employ different sequence-based computational methods to predict the MHC-I and MHC-II T-cell epitopes as well as B-cell epitopes for the complete MARV genome. We analyzed the variations in the predicted epitopes among four MARV variants, the Lake Victoria, Angola, Musoke, and Ravn. We used a consensus approach to identify several epitopes, including novel epitopes, and narrowed down the selection based on different parameters such as antigenicity and IC50 values. The selected epitopes can be used in various vaccine constructs that give effective antibody responses. The MHC-I epitope-allele complexes for GP and NP with favorably low IC50 values were investigated using molecular dynamics computations to determine the molecular details of the epitope-allele complexes. This study provides information for further experimental validation of the potential epitopes and the design and development of MARV vaccines.
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Affiliation(s)
- Prabin Baral
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Elumalai Pavadai
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Ziyou Zhou
- Biotech Group, Luna Labs USA, Charlottesville, VA 22903, USA
| | - Yang Xu
- Biotech Group, Luna Labs USA, Charlottesville, VA 22903, USA
| | | | - Rudramani Pokhrel
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Bernard S Gerstman
- Department of Physics, Florida International University, Miami, FL 33199, USA; Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, FL 33199, USA; Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA.
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11
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Norris MJ, Husby ML, Kiosses WB, Yin J, Saxena R, Rennick LJ, Heiner A, Harkins SS, Pokhrel R, Schendel SL, Hastie KM, Landeras-Bueno S, Salie ZL, Lee B, Chapagain PP, Maisner A, Duprex WP, Stahelin RV, Saphire EO. Measles and Nipah virus assembly: Specific lipid binding drives matrix polymerization. Sci Adv 2022; 8:eabn1440. [PMID: 35857835 PMCID: PMC9299542 DOI: 10.1126/sciadv.abn1440] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 06/06/2022] [Indexed: 05/03/2023]
Abstract
Measles virus, Nipah virus, and multiple other paramyxoviruses cause disease outbreaks in humans and animals worldwide. The paramyxovirus matrix (M) protein mediates virion assembly and budding from host cell membranes. M is thus a key target for antivirals, but few high-resolution structures of paramyxovirus M are available, and we lack the clear understanding of how viral M proteins interact with membrane lipids to mediate viral assembly and egress that is needed to guide antiviral design. Here, we reveal that M proteins associate with phosphatidylserine and phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] at the plasma membrane. Using x-ray crystallography, electron microscopy, and molecular dynamics, we demonstrate that PI(4,5)P2 binding induces conformational and electrostatic changes in the M protein surface that trigger membrane deformation, matrix layer polymerization, and virion assembly.
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Affiliation(s)
- Michael J. Norris
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, La Jolla, CA 92037, USA
| | - Monica L. Husby
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
| | - William B. Kiosses
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, La Jolla, CA 92037, USA
| | - Jieyun Yin
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, La Jolla, CA 92037, USA
| | - Roopashi Saxena
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
| | - Linda J. Rennick
- Center for Vaccine Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Anja Heiner
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | - Stephanie S. Harkins
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, La Jolla, CA 92037, USA
| | - Rudramani Pokhrel
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Sharon L. Schendel
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, La Jolla, CA 92037, USA
| | - Kathryn M. Hastie
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, La Jolla, CA 92037, USA
| | - Sara Landeras-Bueno
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, La Jolla, CA 92037, USA
| | - Zhe Li Salie
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, La Jolla, CA 92037, USA
| | - Benhur Lee
- Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Prem P. Chapagain
- Department of Physics, Florida International University, Miami, FL 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Andrea Maisner
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | - W. Paul Duprex
- Center for Vaccine Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Robert V. Stahelin
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
| | - Erica Ollmann Saphire
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, La Jolla, CA 92037, USA
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12
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Jeanne Dit Fouque K, Sipe SN, Garabedian A, Mejia G, Su L, Hossen ML, Chapagain PP, Leng F, Brodbelt JS, Fernandez-Lima F. Exploring the Conformational and Binding Dynamics of HMGA2·DNA Complexes Using Trapped Ion Mobility Spectrometry-Mass Spectrometry. J Am Soc Mass Spectrom 2022; 33:1103-1112. [PMID: 35687119 PMCID: PMC9280850 DOI: 10.1021/jasms.2c00101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The mammalian high mobility group protein AT-hook 2 (HMGA2) is an intrinsically disordered DNA-binding protein expressed during embryogenesis. In the present work, the conformational and binding dynamics of HMGA2 and HMGA2 in complex with a 22-nt (DNA22) and a 50-nt (DNA50) AT-rich DNA hairpin were investigated using trapped ion mobility spectrometry-mass spectrometry (TIMS-MS) under native starting solvent conditions (e.g., 100 mM aqueous NH4Ac) and collision-induced unfolding/dissociation (CIU/CID) as well as solution fluorescence anisotropy to assess the role of the DNA ligand when binding to the HMGA2 protein. CIU-TIMS-CID-MS/MS experiments showed a significant reduction of the conformational space and charge-state distribution accompanied by an energy stability increase of the native HMGA2 upon DNA binding. Fluorescence anisotropy experiments and CIU-TIMS-CID-MS/MS demonstrated for the first time that HMGA2 binds with high affinity to the minor groove of AT-rich DNA oligomers and with lower affinity to the major groove of AT-rich DNA oligomers (minor groove occupied by a minor groove binder Hoechst 33258). The HMGA2·DNA22 complex (18.2 kDa) 1:1 and 1:2 stoichiometry suggests that two of the AT-hook sites are accessible for DNA binding, while the other AT-hook site is probably coordinated by the C-terminal motif peptide (CTMP). The HMGA2 transition from disordered to ordered upon DNA binding is driven by the interaction of the three basic AT-hook residues with the minor and/or major grooves of AT-rich DNA oligomers.
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Affiliation(s)
- Kevin Jeanne Dit Fouque
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Sarah N Sipe
- Department of Chemistry, University of Texas, Austin, Texas 78712 United States
| | - Alyssa Garabedian
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - German Mejia
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Linjia Su
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Md Lokman Hossen
- Department of Physics, Florida International University, Miami, Florida 33199, United States
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, Florida 33199, United States
- Biomolecular Sciences Institute, Florida International University, Miami, Florida 33199, United States
| | - Fenfei Leng
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
- Biomolecular Sciences Institute, Florida International University, Miami, Florida 33199, United States
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas, Austin, Texas 78712 United States
| | - Francisco Fernandez-Lima
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
- Biomolecular Sciences Institute, Florida International University, Miami, Florida 33199, United States
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13
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Pandey P, Bhattarai N, Su L, Wang X, Leng F, Gerst-man B, Chapagain PP, He J. Detecting Individual Proteins and Their Surface Charge Variations in Solution by the Potentiometric Nanoimpact Method. ACS Sens 2022; 7:555-563. [PMID: 35060380 PMCID: PMC10631516 DOI: 10.1021/acssensors.1c02385] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Label-free detection and analysis of proteins in their natural form and their dynamic interactions with substrates at the single-molecule level are important for both fundamental studies and various applications. Herein, we demonstrate a simple potentiometric method to achieve this goal by detecting the native charge of protein in solution by utilizing the principle of single-entity electrochemistry techniques. When a charged protein moves near the vicinity of a floating carbon nanoelectrode connected to a high-impedance voltage meter, the distinct local electrostatic potential changes induced by the transient collision event of protein, also called the "nanoimpact" event, can be captured by the nanoelectrode as a potential probe. This potentiometric method is highly sensitive for charged proteins, and low-molecular-weight proteins less than 10 kDa can be detected in low-salt-concentration electrolytes. By analyzing the shape and magnitude of the recorded time-resolved potential change and its time derivative, we can reveal the charge and motion of the protein in the nonspecific protein-surface interaction event. The charge polarity variations of the proteins at different pH values were also successfully probed. Compared with synthetic spherical nanoparticles, the statistical analysis of many single-molecule nanoimpact events revealed a large variation in the recorded transient potential signals, which may be attributed to the intrinsic protein dynamics and surface charge heterogeneity, as suggested by the finite element method and molecular dynamic simulations.
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Affiliation(s)
- Popular Pandey
- Physics Department, Florida International University, Miami, Florida, 33199, USA
| | - Nisha Bhattarai
- Physics Department, Florida International University, Miami, Florida, 33199, USA
| | - Linjia Su
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, 33199, USA
| | - Xuewen Wang
- Physics Department, Florida International University, Miami, Florida, 33199, USA
| | - Fenfei Leng
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, Florida, 33199, USA
| | - Bernard Gerst-man
- Physics Department, Florida International University, Miami, Florida, 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, Florida, 33199, USA
| | - Prem P. Chapagain
- Physics Department, Florida International University, Miami, Florida, 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, Florida, 33199, USA
| | - Jin He
- Physics Department, Florida International University, Miami, Florida, 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, Florida, 33199, USA
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14
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Bhattarai N, Pavadai E, Pokhrel R, Baral P, Hossen L, Stahelin RV, Chapagain PP, Gerstman BS. Ebola virus protein VP40 binding to Sec24c for transport to the plasma membrane. Proteins 2022; 90:340-350. [PMID: 34431571 PMCID: PMC8738135 DOI: 10.1002/prot.26221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 07/01/2021] [Accepted: 08/16/2021] [Indexed: 02/03/2023]
Abstract
Outbreaks of the Ebola virus (EBOV) continue to occur and while a vaccine and treatment are now available, there remains a dearth of options for those who become sick with EBOV disease. An understanding at the atomic and molecular level of the various steps in the EBOV replication cycle can provide molecular targets for disrupting the virus. An important step in the EBOV replication cycle is the transport of EBOV structural matrix VP40 protein molecules to the plasma membrane inner leaflet, which involves VP40 binding to the host cell's Sec24c protein. Though some VP40 residues involved in the binding are known, the molecular details of VP40-Sec24c binding are not known. We use various molecular computational techniques to investigate the molecular details of how EBOV VP40 binds with the Sec24c complex of the ESCRT-I pathway. We employed different docking programs to identify the VP40-binding site on Sec24c and then performed molecular dynamics simulations to determine the atomic details and binding interactions of the complex. We also investigated how the inter-protein interactions of the complex are affected upon mutations of VP40 amino acids in the Sec24c-binding region. Our results provide a molecular basis for understanding previous coimmunoprecipitation experimental studies. In addition, we found that VP40 can bind to a site on Sec24c that can also bind Sec23 and suggests that VP40 may use the COPII transport mechanism in a manner that may not need the Sec23 protein in order for VP40 to be transported to the plasma membrane.
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Affiliation(s)
- Nisha Bhattarai
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Elumalai Pavadai
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Rudramani Pokhrel
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Prabin Baral
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Lokman Hossen
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Robert V. Stahelin
- Department of Medicinal Chemistry & Molecular Pharmacology and the Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette IN 47906
| | - Prem P. Chapagain
- Department of Physics, Florida International University, Miami, FL 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Bernard S. Gerstman
- Department of Physics, Florida International University, Miami, FL 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
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15
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Garabedian A, Jeanne Dit Fouque K, Chapagain PP, Leng F, Fernandez-Lima F. OUP accepted manuscript. Nucleic Acids Res 2022; 50:2431-2439. [PMID: 35212375 PMCID: PMC8934665 DOI: 10.1093/nar/gkac115] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 12/30/2021] [Accepted: 02/08/2022] [Indexed: 11/25/2022] Open
Abstract
The mammalian high mobility group protein AT-hook 2 (HMGA2) houses three motifs that preferentially bind short stretches of AT-rich DNA regions. These DNA binding motifs, known as ‘AT-hooks’, are traditionally characterized as being unstructured. Upon binding to AT-rich DNA, they form ordered assemblies. It is this disordered-to-ordered transition that has implicated HMGA2 as a protein actively involved in many biological processes, with abnormal HMGA expression linked to a variety of health problems including diabetes, obesity, and oncogenesis. In the current work, the solution binding dynamics of the three ‘AT-hook’ peptides (ATHPs) with AT-rich DNA hairpin substrates were studied using DNA UV melting studies, fluorescence spectroscopy, native ion mobility spectrometry-mass spectrometry (IMS-MS), solution isothermal titration calorimetry (ITC) and molecular modeling. Results showed that the ATHPs bind to the DNA to form a single, 1:1 and 2:1, ‘key-locked’ conformational ensemble. The molecular models showed that 1:1 and 2:1 complex formation is driven by the capacity of the ATHPs to bind to the minor and major grooves of the AT-rich DNA oligomers. Complementary solution ITC results confirmed that the 2:1 stoichiometry of ATHP: DNA is originated under native conditions in solution.
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Affiliation(s)
- Alyssa Garabedian
- Department of Chemistry and Biochemistry, Florida International University, Miami, 33199, USA
| | - Kevin Jeanne Dit Fouque
- Department of Chemistry and Biochemistry, Florida International University, Miami, 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, 33199, USA
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, 33199, USA
| | - Fenfei Leng
- Department of Chemistry and Biochemistry, Florida International University, Miami, 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, 33199, USA
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16
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Pokhrel R, Bhattarai N, Baral P, Gerstman BS, Park JH, Handfield M, Chapagain PP. Lipid II Binding and Transmembrane Properties of Various Antimicrobial Lanthipeptides. J Chem Theory Comput 2021; 18:516-525. [PMID: 34874159 DOI: 10.1021/acs.jctc.1c00666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
There has been an alarming rise in antibacterial resistant infections in recent years due to the widespread use of antibiotics, and there is a dire need for the development of new antibiotics utilizing novel modes of action. Lantibiotics are promising candidates to engage in the fight against resistant strains of bacteria due to their unique modes of action, including interference with cell wall synthesis by binding to lipid II and creating pores in bacterial membranes. In this study, we use atomic-scale molecular dynamics computational studies to compare both the lipid II binding ability and the membrane interactions of five lanthipeptides that are commonly used in antimicrobial research: nisin, Mutacin 1140 (MU1140), gallidermin, NVB302, and NAI107. Among the five peptides investigated, nisin is found to be the most efficient at forming water channels through a membrane, whereas gallidermin and MU1140 are found to be better at binding the lipid II molecules. Nisin's effectiveness in facilitating water transport across the membrane is due to the creation of several different water trajectories along with no significant water delay points along the paths. The shorter peptide deoxyactagardine B (NVB302) was found to not form a water channel. These detailed observations provide insights into the dual mechanisms of the action of lantibiotic peptides and can facilitate the design and development of novel lanthipeptides by strategic placement of different residues.
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Affiliation(s)
| | | | | | | | - Jae H Park
- Oragenics Inc., Alachua, Florida 32615, United States
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17
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Baral P, Bhattarai N, Hossen ML, Stebliankin V, Gerstman BS, Narasimhan G, Chapagain PP. Mutation-induced changes in the receptor-binding interface of the SARS-CoV-2 Delta variant B.1.617.2 and implications for immune evasion. Biochem Biophys Res Commun 2021; 574:14-19. [PMID: 34425281 PMCID: PMC8364676 DOI: 10.1016/j.bbrc.2021.08.036] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 08/13/2021] [Indexed: 12/15/2022]
Abstract
Following the initial surges of the Alpha (B.1.1.7) and the Beta (B.1.351) variants, a more infectious Delta variant (B.1.617.2) is now surging, further deepening the health crises caused by the pandemic. The sharp rise in cases attributed to the Delta variant has made it especially disturbing and is a variant of concern. Fortunately, current vaccines offer protection against known variants of concern, including the Delta variant. However, the Delta variant has exhibited some ability to dodge the immune system as it is found that neutralizing antibodies from prior infections or vaccines are less receptive to binding with the Delta spike protein. Here, we investigated the structural changes caused by the mutations in the Delta variant's receptor-binding interface and explored the effects on binding with the ACE2 receptor as well as with neutralizing antibodies. We find that the receptor-binding β-loop-β motif adopts an altered but stable conformation causing separation in some of the antibody binding epitopes. Our study shows reduced binding of neutralizing antibodies and provides a possible mechanism for the immune evasion exhibited by the Delta variant.
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Affiliation(s)
- Prabin Baral
- Department of Physics, Florida International University, Miami, FL, 33199, USA
| | - Nisha Bhattarai
- Department of Physics, Florida International University, Miami, FL, 33199, USA
| | - Md Lokman Hossen
- Department of Physics, Florida International University, Miami, FL, 33199, USA
| | - Vitalii Stebliankin
- Bioinformatics Research Group (BioRG), Knight Foundation School of Computing and Information Sciences, Florida International University, Miami, FL, 33199, USA
| | - Bernard S. Gerstman
- Department of Physics, Florida International University, Miami, FL, 33199, USA,Biomolecular Sciences Institute, Florida International University, Miami, FL, 33199, USA
| | - Giri Narasimhan
- Bioinformatics Research Group (BioRG), Knight Foundation School of Computing and Information Sciences, Florida International University, Miami, FL, 33199, USA,Biomolecular Sciences Institute, Florida International University, Miami, FL, 33199, USA
| | - Prem P. Chapagain
- Department of Physics, Florida International University, Miami, FL, 33199, USA,Biomolecular Sciences Institute, Florida International University, Miami, FL, 33199, USA,Corresponding author. Department of Physics, Florida International University, Miami, FL, 33199, USA
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18
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Johnson KA, Bhattarai N, Budicini MR, LaBonia CM, Baker SCB, Gerstman BS, Chapagain PP, Stahelin RV. Cysteine Mutations in the Ebolavirus Matrix Protein VP40 Promote Phosphatidylserine Binding by Increasing the Flexibility of a Lipid-Binding Loop. Viruses 2021; 13:1375. [PMID: 34372582 PMCID: PMC8310056 DOI: 10.3390/v13071375] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 07/08/2021] [Accepted: 07/13/2021] [Indexed: 11/25/2022] Open
Abstract
Ebolavirus (EBOV) is a negative-sense RNA virus that causes severe hemorrhagic fever in humans. The matrix protein VP40 facilitates viral budding by binding to lipids in the host cell plasma membrane and driving the formation of filamentous, pleomorphic virus particles. The C-terminal domain of VP40 contains two highly-conserved cysteine residues at positions 311 and 314, but their role in the viral life cycle is unknown. We therefore investigated the properties of VP40 mutants in which the conserved cysteine residues were replaced with alanine. The C311A mutation significantly increased the affinity of VP40 for membranes containing phosphatidylserine (PS), resulting in the assembly of longer virus-like particles (VLPs) compared to wild-type VP40. The C314A mutation also increased the affinity of VP40 for membranes containing PS, albeit to a lesser degree than C311A. The double mutant behaved in a similar manner to the individual mutants. Computer modeling revealed that both cysteine residues restrain a loop segment containing lysine residues that interact with the plasma membrane, but Cys311 has the dominant role. Accordingly, the C311A mutation increases the flexibility of this membrane-binding loop, changes the profile of hydrogen bonding within VP40 and therefore binds to PS with greater affinity. This is the first evidence that mutations in VP40 can increase its affinity for biological membranes and modify the length of Ebola VLPs. The Cys311 and Cys314 residues therefore play an important role in dynamic interactions at the plasma membrane by modulating the ability of VP40 to bind PS.
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Affiliation(s)
- Kristen A. Johnson
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (K.A.J.); (M.R.B.); (C.M.L.); (S.C.B.B.)
| | - Nisha Bhattarai
- Department of Physics, Florida International University, Miami, FL 33199, USA; (N.B.); (B.S.G.); (P.P.C.)
| | - Melissa R. Budicini
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (K.A.J.); (M.R.B.); (C.M.L.); (S.C.B.B.)
| | - Carolyn M. LaBonia
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (K.A.J.); (M.R.B.); (C.M.L.); (S.C.B.B.)
| | - Sarah Catherine B. Baker
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (K.A.J.); (M.R.B.); (C.M.L.); (S.C.B.B.)
| | - Bernard S. Gerstman
- Department of Physics, Florida International University, Miami, FL 33199, USA; (N.B.); (B.S.G.); (P.P.C.)
- The Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Prem P. Chapagain
- Department of Physics, Florida International University, Miami, FL 33199, USA; (N.B.); (B.S.G.); (P.P.C.)
- The Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Robert V. Stahelin
- Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
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19
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Bhattarai N, Baral P, Gerstman BS, Chapagain PP. Structural and Dynamical Differences in the Spike Protein RBD in the SARS-CoV-2 Variants B.1.1.7 and B.1.351. J Phys Chem B 2021; 125:7101-7107. [PMID: 34110159 PMCID: PMC8204914 DOI: 10.1021/acs.jpcb.1c01626] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 05/25/2021] [Indexed: 12/13/2022]
Abstract
The novel coronavirus (SARS-CoV-2) pandemic that started in late 2019 is responsible for hundreds of millions of cases worldwide and millions of fatalities. Though vaccines are available, the virus is mutating to form new strains among which are the variants B.1.1.7 and B.1.351 that demonstrate increased transmissivity and infectivity. In this study, we performed molecular dynamics simulations to explore the role of the mutations in the interaction of the virus spike protein receptor binding domain (RBD) with the host receptor ACE2. We find that the hydrogen bond networks are rearranged in the variants and also that new hydrogen bonds are established between the RBD and ACE2 as a result of mutations. We investigated three variants: the wild-type (WT), B.1.1.7, and B.1.351. We find that the B.1.351 variant (also known as 501Y.V2) shows larger flexibility in the RBD loop segment involving residue K484, yet the RBD-ACE2 complex shows higher stability. Mutations that allow a more flexible interface that can result in a more stable complex may be a factor contributing to the increased infectivity of the mutated variants.
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Affiliation(s)
- Nisha Bhattarai
- Department of Physics, Florida
International University, Miami, Florida 33199, United
States
| | - Prabin Baral
- Department of Physics, Florida
International University, Miami, Florida 33199, United
States
| | - Bernard S. Gerstman
- Department of Physics, Florida
International University, Miami, Florida 33199, United
States
- Biomolecular Sciences Institute, Florida
International University, Miami, Florida 33199, United
States
| | - Prem P. Chapagain
- Department of Physics, Florida
International University, Miami, Florida 33199, United
States
- Biomolecular Sciences Institute, Florida
International University, Miami, Florida 33199, United
States
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20
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Koirala RP, Pokhrel R, Baral P, Tiwari PB, Chapagain PP, Adhikari NP. Structural insights into the repair mechanism of AGT for methyl-induced DNA damage. Biol Chem 2021; 402:1203-1211. [PMID: 34192828 DOI: 10.1515/hsz-2021-0198] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/29/2021] [Indexed: 02/06/2023]
Abstract
Methylation induced DNA base-pairing damage is one of the major causes of cancer. O6-alkylguanine-DNA alkyltransferase (AGT) is considered a demethylation agent of the methylated DNA. Structural investigations with thermodynamic properties of the AGT-DNA complex are still lacking. In this report, we modeled two catalytic states of AGT-DNA interactions and an AGT-DNA covalent complex and explored structural features using molecular dynamics (MD) simulations. We utilized the umbrella sampling method to investigate the changes in the free energy of the interactions in two different AGT-DNA catalytic states, one with methylated GUA in DNA and the other with methylated CYS145 in AGT. These non-covalent complexes represent the pre- and post-repair complexes. Therefore, our study encompasses the process of recognition, complex formation, and separation of the AGT and the damaged (methylated) DNA base. We believe that the use of parameters for the amino acid and nucleotide modifications and for the protein-DNA covalent bond will allow investigations of the DNA repair mechanism as well as the exploration of cancer therapeutics targeting the AGT-DNA complexes at various functional states as well as explorations via stabilization of the complex.
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Affiliation(s)
| | - Rudramani Pokhrel
- Department of Physics, Florida International University, Miami, FL, USA
| | - Prabin Baral
- Department of Physics, Florida International University, Miami, FL, USA
| | | | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, FL, USA.,Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
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21
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Amiar S, Husby ML, Wijesinghe KJ, Angel S, Bhattarai N, Gerstman BS, Chapagain PP, Li S, Stahelin RV. Lipid-specific oligomerization of the Marburg virus matrix protein VP40 is regulated by two distinct interfaces for virion assembly. J Biol Chem 2021; 296:100796. [PMID: 34019871 PMCID: PMC8191294 DOI: 10.1016/j.jbc.2021.100796] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 02/03/2023] Open
Abstract
Marburg virus (MARV) is a lipid-enveloped virus harboring a negative-sense RNA genome, which has caused sporadic outbreaks of viral hemorrhagic fever in sub-Saharan Africa. MARV assembles and buds from the host cell plasma membrane where MARV matrix protein (mVP40) dimers associate with anionic lipids at the plasma membrane inner leaflet and undergo a dynamic and extensive self-oligomerization into the structural matrix layer. The MARV matrix layer confers the virion filamentous shape and stability but how host lipids modulate mVP40 oligomerization is mostly unknown. Using in vitro and cellular techniques, we present a mVP40 assembly model highlighting two distinct oligomerization interfaces: the (N-terminal domain [NTD] and C-terminal domain [CTD]) in mVP40. Cellular studies of NTD and CTD oligomerization interface mutants demonstrate the importance of each interface in matrix assembly. The assembly steps include protein trafficking to the plasma membrane, homo-multimerization that induced protein enrichment, plasma membrane fluidity changes, and elongations at the plasma membrane. An ascorbate peroxidase derivative (APEX)-transmission electron microscopy method was employed to closely assess the ultrastructural localization and formation of viral particles for wildtype mVP40 and NTD and CTD oligomerization interface mutants. Taken together, these studies present a mechanistic model of mVP40 oligomerization and assembly at the plasma membrane during virion assembly that requires interactions with phosphatidylserine for NTD–NTD interactions and phosphatidylinositol-4,5-bisphosphate for proper CTD–CTD interactions. These findings have broader implications in understanding budding of lipid-enveloped viruses from the host cell plasma membrane and potential strategies to target protein–protein or lipid–protein interactions to inhibit virus budding.
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Affiliation(s)
- Souad Amiar
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA
| | - Monica L Husby
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA
| | - Kaveesha J Wijesinghe
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA; Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Stephanie Angel
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA
| | - Nisha Bhattarai
- Department of Physics, Florida International University, Miami, Florida, USA
| | - Bernard S Gerstman
- Department of Physics, Florida International University, Miami, Florida, USA; Biomolecular Sciences Institute, Florida International University, Miami, Florida, USA
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, Florida, USA; Biomolecular Sciences Institute, Florida International University, Miami, Florida, USA
| | - Sheng Li
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Robert V Stahelin
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA.
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22
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Bhattarai N, Gerstman B, Chapagain PP. Effects of G198R Mutation in the Ebola VP40 Matrix Protein: A Molecular Dynamics Study. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.1934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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23
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Su L, Bryan N, Battista S, Freitas J, Garabedian A, D'Alessio F, Romano M, Falanga F, Fusco A, Kos L, Chambers J, Fernandez-Lima F, Chapagain PP, Vasile S, Smith L, Leng F. Identification of HMGA2 inhibitors by AlphaScreen-based ultra-high-throughput screening assays. Sci Rep 2020; 10:18850. [PMID: 33139812 PMCID: PMC7606612 DOI: 10.1038/s41598-020-75890-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 10/19/2020] [Indexed: 11/25/2022] Open
Abstract
The mammalian high mobility group protein AT-hook 2 (HMGA2) is a multi-functional DNA-binding protein that plays important roles in tumorigenesis and adipogenesis. Previous results showed that HMGA2 is a potential therapeutic target of anticancer and anti-obesity drugs by inhibiting its DNA-binding activities. Here we report the development of a miniaturized, automated AlphaScreen ultra-high-throughput screening assay to identify inhibitors targeting HMGA2-DNA interactions. After screening the LOPAC1280 compound library, we identified several compounds that strongly inhibit HMGA2-DNA interactions including suramin, a century-old, negatively charged antiparasitic drug. Our results show that the inhibition is likely through suramin binding to the "AT-hook" DNA-binding motifs and therefore preventing HMGA2 from binding to the minor groove of AT-rich DNA sequences. Since HMGA1 proteins also carry multiple "AT-hook" DNA-binding motifs, suramin is expected to inhibit HMGA1-DNA interactions as well. Biochemical and biophysical studies show that charge-charge interactions and hydrogen bonding between the suramin sulfonated groups and Arg/Lys residues play critical roles in the binding of suramin to the "AT-hook" DNA-binding motifs. Furthermore, our results suggest that HMGA2 may be one of suramin's cellular targets.
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Affiliation(s)
- Linjia Su
- Biomolecular Sciences Institute, Florida International University, Miami, FL, 33199, USA
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL, 33199, USA
| | - Nadezda Bryan
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, FL, 32827, USA
| | - Sabrina Battista
- Istituto per l'Endocrinologia e l'Oncologia Sperimentale, CNR, Via Pansini 5, 80131, Naples, Italy
| | - Juliano Freitas
- Biomolecular Sciences Institute, Florida International University, Miami, FL, 33199, USA
- Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA
| | - Alyssa Garabedian
- Biomolecular Sciences Institute, Florida International University, Miami, FL, 33199, USA
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL, 33199, USA
| | - Federica D'Alessio
- Dipartimento Di Medicina Molecolare E Biotecnologie Mediche, Università Degli Studi "Federico II" Di Napoli, Naples, Italy
| | - Miriam Romano
- Dipartimento Di Medicina Molecolare E Biotecnologie Mediche, Università Degli Studi "Federico II" Di Napoli, Naples, Italy
| | - Fabiana Falanga
- Dipartimento Di Medicina Molecolare E Biotecnologie Mediche, Università Degli Studi "Federico II" Di Napoli, Naples, Italy
| | - Alfredo Fusco
- Dipartimento Di Medicina Molecolare E Biotecnologie Mediche, Università Degli Studi "Federico II" Di Napoli, Naples, Italy
| | - Lidia Kos
- Biomolecular Sciences Institute, Florida International University, Miami, FL, 33199, USA
- Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA
| | - Jeremy Chambers
- Biomolecular Sciences Institute, Florida International University, Miami, FL, 33199, USA
- Department of Environmental Health Sciences, Florida International University, Miami, FL, 33199, USA
| | - Francisco Fernandez-Lima
- Biomolecular Sciences Institute, Florida International University, Miami, FL, 33199, USA
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL, 33199, USA
| | - Prem P Chapagain
- Biomolecular Sciences Institute, Florida International University, Miami, FL, 33199, USA
- Department of Physics, Florida International University, Miami, FL, 33199, USA
| | - Stefan Vasile
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, FL, 32827, USA
| | - Layton Smith
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, FL, 32827, USA
| | - Fenfei Leng
- Biomolecular Sciences Institute, Florida International University, Miami, FL, 33199, USA.
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL, 33199, USA.
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Beddingfield BJ, Iwanaga N, Chapagain PP, Zheng W, Roy CJ, Hu TY, Kolls JK, Bix GJ. The Integrin Binding Peptide, ATN-161, as a Novel Therapy for SARS-CoV-2 Infection. ACTA ACUST UNITED AC 2020; 6:1-8. [PMID: 33102950 PMCID: PMC7566794 DOI: 10.1016/j.jacbts.2020.10.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/05/2020] [Accepted: 10/06/2020] [Indexed: 01/10/2023]
Abstract
Many efforts to design and screen therapeutics for the current severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) pandemic have focused on inhibiting viral host cell entry by disrupting angiotensin-converting enzyme-2 (ACE2) binding with the SARS-CoV-2 spike protein. This work focuses on the potential to inhibit SARS-CoV-2 entry through a hypothesized α5β1 integrin-based mechanism and indicates that inhibiting the spike protein interaction with α5β1 integrin (+/- ACE2) and the interaction between α5β1 integrin and ACE2 using a novel molecule (ATN-161) represents a promising approach to treat coronavirus disease-19.
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Key Words
- ACE2
- ACE2, angiotensin-converting enzyme 2
- ATN-161
- CO2, carbon dioxide
- COVID-19
- COVID-19, coronavirus disease-2019
- DMEM, Dulbecco’s modified eagle media
- ELISA, enzyme-linked immunosorbent assay
- IC50, half-maximal inhibitory concentration
- RBD, receptor binding domain
- RGD, arginine-glycine-aspartate
- SARS-CoV-2
- SARS-CoV-2, severe acute respiratory syndrome-coronavirus-2
- alpha5beta1 integrin
- hACE2, human angiotensin-converting enzyme 2
- host-cell entry
- qPCR, quantitative polymerase chain reaction
- receptor binding domain
- therapeutic
- viral spike protein
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Affiliation(s)
- Brandon J. Beddingfield
- Division of Microbiology, Tulane National Primate Research Center, Covington, Louisiana, USA
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Naoki Iwanaga
- Departments of Pediatrics and Medicine, Center for Translational Research in Infection and Inflammation, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Prem P. Chapagain
- Department of Physics, Florida International University, Miami, Florida, USA
- Biomolecular Sciences Institute, Florida International University, Miami, Florida, USA
| | - Wenshu Zheng
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Chad J. Roy
- Division of Microbiology, Tulane National Primate Research Center, Covington, Louisiana, USA
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Tony Y. Hu
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Jay K. Kolls
- Departments of Pediatrics and Medicine, Center for Translational Research in Infection and Inflammation, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Gregory J. Bix
- Clinical Neuroscience Research Center, Tulane University School of Medicine, New Orleans, Louisiana, USA
- Department of Neurosurgery, Tulane University School of Medicine, New Orleans, Louisiana, USA
- Department of Neurology, Tulane University School of Medicine, New Orleans, Louisiana, USA
- Tulane Brain Institute, Tulane University, New Orleans, Louisiana, USA
- Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana, USA
- Address for correspondence: Dr. Gregory J. Bix, Tulane University School of Medicine, Clinical Neuroscience Research Center, 131 South Robertson, Suite 1300, Room 1349, New Orleans, Louisiana 70112, USA.
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Azam S, Bhattarai N, Riveron A, Rodriguez S, Chapagain PP, Miksovska J. EF-hands in Neuronal Calcium Sensor Downstream Regulatory Element Antagonist Modulator Demonstrate Submillimolar Affinity for Li +: A New Prospect for Li + Therapy. ACS Chem Neurosci 2020; 11:2543-2548. [PMID: 32786300 DOI: 10.1021/acschemneuro.0c00399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Lithium has been used for the treatment of mood disorders for decades though the molecular mechanism of its therapeutic action and intracellular targets remain furtive. We report that neurotropic agent Li+ binds to the neuronal calcium sensor, Downstream Regulatory Element Antagonist Modulator (DREAM), with an equilibrium dissociation constant of 34 ± 4 μM and impacts DREAM structural and dynamic properties in a similar manner as observed for its physiological ligand, Ca2+. Results of fluorescence spectroscopy and molecular dynamics are consistent with Li+ binding at EF-hands. In the Li+ bound form, DREAM association to peptides mimicking DREAM binding sites in a voltage-gated potassium channel is enhanced compared to the apoprotein, whereas DREAM affinity for the presenilin binding site, helix-9, is impeded. These results suggest that DREAM and possibly other members of the neuronal calcium sensor family belong to Li+ intracellular targets and interactions between Li+ and NCS provide a molecular basis for Li+ neuroprotective action.
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26
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Wijesinghe KJ, McVeigh L, Husby ML, Bhattarai N, Ma J, Gerstman BS, Chapagain PP, Stahelin RV. Mutation of Hydrophobic Residues in the C-Terminal Domain of the Marburg Virus Matrix Protein VP40 Disrupts Trafficking to the Plasma Membrane. Viruses 2020; 12:v12040482. [PMID: 32344654 PMCID: PMC7232359 DOI: 10.3390/v12040482] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/14/2020] [Accepted: 04/22/2020] [Indexed: 12/13/2022] Open
Abstract
Marburg virus (MARV) is a lipid-enveloped negative sense single stranded RNA virus, which can cause a deadly hemorrhagic fever. MARV encodes seven proteins, including VP40 (mVP40), a matrix protein that interacts with the cytoplasmic leaflet of the host cell plasma membrane. VP40 traffics to the plasma membrane inner leaflet, where it assembles to facilitate the budding of viral particles. VP40 is a multifunctional protein that interacts with several host proteins and lipids to complete the viral replication cycle, but many of these host interactions remain unknown or are poorly characterized. In this study, we investigated the role of a hydrophobic loop region in the carboxy-terminal domain (CTD) of mVP40 that shares sequence similarity with the CTD of Ebola virus VP40 (eVP40). These conserved hydrophobic residues in eVP40 have been previously shown to be critical to plasma membrane localization and membrane insertion. An array of cellular experiments and confirmatory in vitro work strongly suggests proper orientation and hydrophobic residues (Phe281, Leu283, and Phe286) in the mVP40 CTD are critical to plasma membrane localization. In line with the different functions proposed for eVP40 and mVP40 CTD hydrophobic residues, molecular dynamics simulations demonstrate large flexibility of residues in the EBOV CTD whereas conserved mVP40 hydrophobic residues are more restricted in their flexibility. This study sheds further light on important amino acids and structural features in mVP40 required for its plasma membrane localization as well as differences in the functional role of CTD amino acids in eVP40 and mVP40.
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Affiliation(s)
- Kaveesha J. Wijesinghe
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (K.J.W.); (L.M.)
| | - Luke McVeigh
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (K.J.W.); (L.M.)
| | - Monica L. Husby
- Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue Institute for Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA;
| | - Nisha Bhattarai
- Department of Physics, Florida International University, Miami, FL 33199, USA; (N.B.); (B.S.G.); (P.P.C.)
| | - Jia Ma
- Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907, USA;
| | - Bernard S. Gerstman
- Department of Physics, Florida International University, Miami, FL 33199, USA; (N.B.); (B.S.G.); (P.P.C.)
- Biomolecules Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Prem P. Chapagain
- Department of Physics, Florida International University, Miami, FL 33199, USA; (N.B.); (B.S.G.); (P.P.C.)
- Biomolecules Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Robert V. Stahelin
- Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue Institute for Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA;
- Correspondence: ; Tel.: +1-765-494-4152
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27
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Tiwari PB, Chapagain PP, Seddek A, Annamalai T, Üren A, Tse-Dinh YC. Covalent Complex of DNA and Bacterial Topoisomerase: Implications in Antibacterial Drug Development. ChemMedChem 2020; 15:623-631. [PMID: 32043806 PMCID: PMC7133791 DOI: 10.1002/cmdc.201900721] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Indexed: 12/11/2022]
Abstract
A topoisomerase-DNA transient covalent complex can be a druggable target for novel topoisomerase poison inhibitors that represent a new class of antibacterial or anticancer drugs. Herein, we have investigated molecular features of the functionally important Escherichia coli topoisomerase I (EctopoI)-DNA covalent complex (EctopoIcc) for molecular simulations, which is very useful in the development of new antibacterial drugs. To demonstrate the usefulness of our approach, we used a model small molecule (SM), NSC76027, obtained from virtual screening. We examined the direct binding of NSC76027 to EctopoI as well as inhibition of EctopoI relaxation activity of this SM via experimental techniques. We then performed molecular dynamics (MD) simulations to investigate the dynamics and stability of EctopoIcc and EctopoI-NSC76027-DNA ternary complex. Our simulation results show that NSC76027 forms a stable ternary complex with EctopoIcc. EctopoI investigated here also serves as a model system for investigating a complex of topoisomerase and DNA in which DNA is covalently attached to the protein.
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Affiliation(s)
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, FL 33199, USA
- Biomolecular sciences institute, Florida International University, Miami, FL 33199, USA
| | - Ahmed Seddek
- Biomolecular sciences institute, Florida International University, Miami, FL 33199, USA
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | - Thirunavukkarasu Annamalai
- Biomolecular sciences institute, Florida International University, Miami, FL 33199, USA
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | - Aykut Üren
- Department of Oncology, Georgetown University, Washington, DC 20057, USA
| | - Yuk-Ching Tse-Dinh
- Biomolecular sciences institute, Florida International University, Miami, FL 33199, USA
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
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28
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Bhattarai N, Gerstman BS, Chapagain PP. Computational Study of the Molecular Details of Ebola Virus Matrix Protein VP40 and Human Sec24C Protein Interaction. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.2787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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29
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Pokhrel R, Pavadai E, Gerstman B, Chapagain PP. Ion Selective Pentameric Pore Formation by Ebola Virus Delta Peptide. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.3181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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30
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Baral P, Pavadai E, Gerstman B, Chapagain PP. Lassa Virus Epitope-Allele Complexes Identified through Computational Modeling. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.1727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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31
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Pavadai E, Bhattarai N, Baral P, Stahelin RV, Chapagain PP, Gerstman BS. Conformational Flexibility of the Protein-Protein Interfaces of the Ebola Virus VP40 Structural Matrix Filament. J Phys Chem B 2019; 123:9045-9053. [PMID: 31576755 DOI: 10.1021/acs.jpcb.9b04674] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The Ebola virus (EBOV) is a virulent pathogen that causes severe hemorrhagic fever with a high fatality rate in humans. The EBOV transformer protein VP40 plays crucial roles in viral assembly and budding at the plasma membrane of infected cells. One of VP40's roles is to form the long, flexible, pleomorphic filamentous structural matrix for the virus. Each filament contains three unique interfaces: monomer NTD-NTD to form a dimer, dimer-to-dimer NTD-NTD oligomerization to form a hexamer, and end-to-end hexamer CTD-CTD to build the filament. However, the atomic-level details of conformational flexibility of the VP40 filament are still elusive. In this study, we have performed explicit-solvent, all-atom molecular dynamic simulations to explore the conformational flexibility of the three different interface structures of the filament. Using dynamic network analysis and other calculational methods, we find that the CTD-CTD hexamer interface with weak interdomain amino acid communities is the most flexible, and the NTD-NTD oligomer interface with strong interdomain communities is the least flexible. Our study suggests that the high flexibility of the CTD-CTD interface may be essential for the supple bending of the Ebola filovirus, and such flexibility may present a target for molecular interventions to disrupt the Ebola virus functioning.
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Affiliation(s)
| | | | | | - Robert V Stahelin
- Department of Medicinal Chemistry and Molecular Pharmacology and the Purdue University Cancer Center , Purdue University , West Lafayette , Indiana 47907 , United States
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32
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Baral P, Bhattarai N, Pokhrel R, Gerstman B, Chapagain PP. Molecular Dynamics Investigations of Enzyme Conformational Changes. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.1031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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33
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Pokhrel R, Bhattarai N, Baral P, Gerstman BS, Park JH, Handfield M, Chapagain PP. Molecular mechanisms of pore formation and membrane disruption by the antimicrobial lantibiotic peptide Mutacin 1140. Phys Chem Chem Phys 2019; 21:12530-12539. [DOI: 10.1039/c9cp01558b] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The emergence of antibiotic-resistance is a major concern to global human health and identification of novel antibiotics is critical to mitigate the threat.
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Affiliation(s)
| | - Nisha Bhattarai
- Department of Physics
- Florida International University
- Miami
- USA
| | - Prabin Baral
- Department of Physics
- Florida International University
- Miami
- USA
| | - Bernard S. Gerstman
- Department of Physics
- Florida International University
- Miami
- USA
- Biomolecular Sciences Institute
| | | | | | - Prem P. Chapagain
- Department of Physics
- Florida International University
- Miami
- USA
- Biomolecular Sciences Institute
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34
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Pokhrel R, Pavadai E, Gerstman BS, Chapagain PP. Membrane pore formation and ion selectivity of the Ebola virus delta peptide. Phys Chem Chem Phys 2019; 21:5578-5585. [DOI: 10.1039/c8cp07323f] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The Ebola virus delta peptide homo-oligomerizes in the host cell membrane to form amphipathic pores that alter the membrane properties.
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Affiliation(s)
| | | | - Bernard S. Gerstman
- Department of Physics
- Miami
- USA
- Biomolecular Sciences Institute Florida International University
- Miami
| | - Prem P. Chapagain
- Department of Physics
- Miami
- USA
- Biomolecular Sciences Institute Florida International University
- Miami
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35
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Gerstman BS, Chapagain PP, Gc J, Steckmann T. Molecular Dynamics Simulations of Conformational Conversions in Transformer Proteins. Methods Mol Biol 2019; 1958:297-311. [PMID: 30945225 DOI: 10.1007/978-1-4939-9161-7_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A relatively recently discovered class of proteins known as transformer proteins undergo large-scale conformational conversions that change their supersecondary structure. These structural transformations lead to different configurations that perform different functions. We describe computational methods using molecular dynamics simulations that allow the determination of the specific amino acids that facilitate the conformational transformations. These investigations provide guidance on the location and type of amino acid mutations that can either enhance or inhibit the structural transitions that allow transformer proteins to perform multiple functions.
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Affiliation(s)
- Bernard S Gerstman
- Department of Physics, Florida International University, Miami, FL, USA.
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, FL, USA
| | - Jeevan Gc
- Department of Physics, Florida International University, Miami, FL, USA
| | - Timothy Steckmann
- Department of Physics, Florida International University, Miami, FL, USA
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36
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Abstract
The formation of a complex between neuroglobin (Ngb) and cytochrome c (Cyt c) has an important biological role in preventing apoptosis. Binding of Ngb to Cyt c alone is sufficient to block the caspase 9 activation by ferric Cyt c that is released during ischemic insults. Therefore, a detailed information on the Ngb-Cyt c interactions is important for understanding apoptosis. However, the exact nature of the interactions between oxidized human neuroglobin (hNgb) and Cyt c is not well understood. In this work, we used a combination of computational modeling and surface plasmon resonance experiments to obtain and characterize the complex formation between oxidized hNgb and Cyt c. We identified important residues involved in the complex formation, including K72 in Cyt c, which is otherwise known to interact with the apoptotic protease-activation factor-1. Our computational results, together with an optimized structure of the hNgb-Cyt c complex, provide unique insights into how the hNgb-Cyt c complex can abate the apoptotic cascade without an hNgb-Cyt c redox reaction.
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Affiliation(s)
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, FL, USA
- Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Aykut Üren
- Department of Oncology, Georgetown University, Washington D.C., USA
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Pavadai E, Gerstman BS, Chapagain PP. A cylindrical assembly model and dynamics of the Ebola virus VP40 structural matrix. Sci Rep 2018; 8:9776. [PMID: 29950600 PMCID: PMC6021417 DOI: 10.1038/s41598-018-28077-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 06/14/2018] [Indexed: 12/01/2022] Open
Abstract
The Ebola filovirus causes severe hemorrhagic fever with a high fatality rate in humans. The primary structural matrix protein VP40 displays transformer-protein characteristics and exists in different conformational and oligomeric states. VP40 plays crucial roles in viral assembly and budding at the plasma membrane of the infected cells and is capable of forming virus-like particles without the need for other Ebola proteins. However, no experimental three-dimensional structure for any filovirus VP40 cylindrical assembly matrix is currently available. Here, we use a protein-protein docking approach to develop cylindrical assembly models for an Ebola virion and also for a smaller structural matrix that does not contain genetic material. These models match well with the 2D averages of cryo-electron tomograms of the authentic virion. We also used all-atom molecular dynamics simulations to investigate the stability and dynamics of the cylindrical models and the interactions between the side-by-side hexamers to determine the amino acid residues that are especially important for stabilizing the hexamers in the cylindrical ring configuration matrix assembly. Our models provide helpful information to better understand the assembly processes of filoviruses and such structural studies may also lead to the design and development of antiviral drugs.
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Affiliation(s)
- Elumalai Pavadai
- Department of Physics, Florida International University, Miami, Florida, 33199, USA.
| | - Bernard S Gerstman
- Department of Physics, Florida International University, Miami, Florida, 33199, USA.,Biomolecular Sciences Institute, Florida International University, Miami, Florida, 33199, USA
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, Florida, 33199, USA.,Biomolecular Sciences Institute, Florida International University, Miami, Florida, 33199, USA
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38
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Pokhrel R, Gerstman BS, Hutcheson JD, Chapagain PP. In Silico Investigations of Calcium Phosphate Mineralization in Extracellular Vesicles. J Phys Chem B 2018. [PMID: 29519123 DOI: 10.1021/acs.jpcb.8b00169] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Calcification in bone, cartilage, and cardiovascular tissues involves the release of specialized extracellular vesicles (EVs) that promote mineral nucleation. The small size of the EVs, however, makes molecular level studies difficult, and consequently uncertainty exists on the role and function of these structures in directing mineralization. The lack of mechanistic understanding associated with the initiators of ectopic mineral deposition has severely hindered the development of potential therapeutic options. Here, we used multiscale molecular dynamics simulations to investigate the calcification within the EVs. Results show that Ca2+-HPO42- and phosphatidylserine complexes facilitate the early nucleation. Use of coarse-grained simulations allows investigations of Ca2+-PO43- nucleation and crystallization in the EVs. Systematic variation in the ion-to-water ratio shows that the crystallization and growth strongly depend on the enrichment of the ions and dehydration inside the EVs. Our investigations provide insights into the role of EVs on calcium phosphate mineral nucleation and growth in both physiological and pathological mineralization.
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Bhattarai N, Chapagain PP, Gerstman BS. Conformational Changes in Marburg Virus VP40 upon Plasma Membrane Association. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.2536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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40
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Pavadai E, Gerstman BS, Chapagain PP. A Cylindrical Assembly Model and Dynamics of the Ebola Virus VP40. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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41
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Del Vecchio K, Frick CT, Gc JB, Oda SI, Gerstman BS, Saphire EO, Chapagain PP, Stahelin RV. A cationic, C-terminal patch and structural rearrangements in Ebola virus matrix VP40 protein control its interactions with phosphatidylserine. J Biol Chem 2018; 293:3335-3349. [PMID: 29348171 DOI: 10.1074/jbc.m117.816280] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 01/08/2018] [Indexed: 02/04/2023] Open
Abstract
Ebola virus (EBOV) is a filamentous lipid-enveloped virus that causes hemorrhagic fever with a high fatality rate. Viral protein 40 (VP40) is the major EBOV matrix protein and regulates viral budding from the plasma membrane. VP40 is a transformer/morpheein that can structurally rearrange its native homodimer into either a hexameric filament that facilitates viral budding or an RNA-binding octameric ring that regulates viral transcription. VP40 associates with plasma-membrane lipids such as phosphatidylserine (PS), and this association is critical to budding from the host cell. However, it is poorly understood how different VP40 structures interact with PS, what essential residues are involved in this association, and whether VP40 has true selectivity for PS among different glycerophospholipid headgroups. In this study, we used lipid-binding assays, MD simulations, and cellular imaging to investigate the molecular basis of VP40-PS interactions and to determine whether different VP40 structures (i.e. monomer, dimer, and octamer) can interact with PS-containing membranes. Results from quantitative analysis indicated that VP40 associates with PS vesicles via a cationic patch in the C-terminal domain (Lys224, 225 and Lys274, 275). Substitutions of these residues with alanine reduced PS-vesicle binding by >40-fold and abrogated VP40 localization to the plasma membrane. Dimeric VP40 had 2-fold greater affinity for PS-containing membranes than the monomer, whereas binding of the VP40 octameric ring was reduced by nearly 10-fold. Taken together, these results suggest the different VP40 structures known to form in the viral life cycle harbor different affinities for PS-containing membranes.
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Affiliation(s)
- Kathryn Del Vecchio
- From the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - Cary T Frick
- From the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | | | | | | | - Erica Ollmann Saphire
- the Department of Immunology and Microbiology and.,The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, and
| | - Prem P Chapagain
- the Department of Physics and.,Biomolecular Sciences Institute, Florida International University, Miami, Florida 33199
| | - Robert V Stahelin
- From the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, .,the Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907
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42
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Gc JB, Pokhrel R, Bhattarai N, Johnson KA, Gerstman BS, Stahelin RV, Chapagain PP. Graphene-VP40 interactions and potential disruption of the Ebola virus matrix filaments. Biochem Biophys Res Commun 2017; 493:176-181. [PMID: 28917841 DOI: 10.1016/j.bbrc.2017.09.052] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 09/11/2017] [Indexed: 02/02/2023]
Abstract
Ebola virus infections cause hemorrhagic fever that often results in very high fatality rates. In addition to exploring vaccines, development of drugs is also essential for treating the disease and preventing the spread of the infection. The Ebola virus matrix protein VP40 exists in various conformational and oligomeric forms and is a potential pharmacological target for disrupting the virus life-cycle. Here we explored graphene-VP40 interactions using molecular dynamics simulations and graphene pelleting assays. We found that graphene sheets associate strongly with VP40 at various interfaces. We also found that the graphene is able to disrupt the C-terminal domain (CTD-CTD) interface of VP40 hexamers. This VP40 hexamer-hexamer interface is crucial in forming the Ebola viral matrix and disruption of this interface may provide a method to use graphene or similar nanoparticle based solutions as a disinfectant that can significantly reduce the spread of the disease and prevent an Ebola epidemic.
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Affiliation(s)
- Jeevan B Gc
- Department of Physics, Florida International University, Miami, FL 33199, United States
| | - Rudramani Pokhrel
- Department of Physics, Florida International University, Miami, FL 33199, United States
| | - Nisha Bhattarai
- Department of Physics, Florida International University, Miami, FL 33199, United States
| | - Kristen A Johnson
- Department of Chemistry and Biochemistry, The Eck Institute for Global Health, The Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, IN 46556, United States
| | - Bernard S Gerstman
- Department of Physics, Florida International University, Miami, FL 33199, United States; Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, United States
| | - Robert V Stahelin
- Department of Chemistry and Biochemistry, The Eck Institute for Global Health, The Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, IN 46556, United States; Department of Biochemistry and Molecular Biology, Indiana University School of Medicine-South Bend, South Bend, IN 46617, United States
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, FL 33199, United States; Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, United States.
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43
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Steckmann T, Bhandari YR, Chapagain PP, Gerstman BS. Cooperative structural transitions in amyloid-like aggregation. J Chem Phys 2017; 146:135103. [DOI: 10.1063/1.4979516] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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44
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Wijesinghe KJ, Urata S, Bhattarai N, Kooijman EE, Gerstman BS, Chapagain PP, Li S, Stahelin RV. Detection of lipid-induced structural changes of the Marburg virus matrix protein VP40 using hydrogen/deuterium exchange-mass spectrometry. J Biol Chem 2017; 292:6108-6122. [PMID: 28167534 PMCID: PMC5391744 DOI: 10.1074/jbc.m116.758300] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 01/30/2017] [Indexed: 11/06/2022] Open
Abstract
Marburg virus (MARV) is a lipid-enveloped virus from the Filoviridae family containing a negative sense RNA genome. One of the seven MARV genes encodes the matrix protein VP40, which forms a matrix layer beneath the plasma membrane inner leaflet to facilitate budding from the host cell. MARV VP40 (mVP40) has been shown to be a dimeric peripheral protein with a broad and flat basic surface that can associate with anionic phospholipids such as phosphatidylserine. Although a number of mVP40 cationic residues have been shown to facilitate binding to membranes containing anionic lipids, much less is known on how mVP40 assembles to form the matrix layer following membrane binding. Here we have used hydrogen/deuterium exchange (HDX) mass spectrometry to determine the solvent accessibility of mVP40 residues in the absence and presence of phosphatidylserine and phosphatidylinositol 4,5-bisphosphate. HDX analysis demonstrates that two basic loops in the mVP40 C-terminal domain make important contributions to anionic membrane binding and also reveals a potential oligomerization interface in the C-terminal domain as well as a conserved oligomerization interface in the mVP40 N-terminal domain. Lipid binding assays confirm the role of the two basic patches elucidated with HD/X measurements, whereas molecular dynamics simulations and membrane insertion measurements complement these studies to demonstrate that mVP40 does not appreciably insert into the hydrocarbon region of anionic membranes in contrast to the matrix protein from Ebola virus. Taken together, we propose a model by which association of the mVP40 dimer with the anionic plasma membrane facilitates assembly of mVP40 oligomers.
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Affiliation(s)
- Kaveesha J Wijesinghe
- From the Department of Chemistry and Biochemistry, The Eck Institute for Global Health and The Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, Indiana 46556
| | - Sarah Urata
- the Department of Medicine, University of California, San Diego, La Jolla, California 92093-0652
| | | | - Edgar E Kooijman
- the Department of Biological Sciences, Kent State University, Kent, Ohio 44242, and
| | - Bernard S Gerstman
- the Departments of Physics and.,Biomolecular Sciences Institute, Florida International University, Miami, Florida 33199
| | - Prem P Chapagain
- the Departments of Physics and.,Biomolecular Sciences Institute, Florida International University, Miami, Florida 33199
| | - Sheng Li
- the Department of Medicine, University of California, San Diego, La Jolla, California 92093-0652,
| | - Robert V Stahelin
- From the Department of Chemistry and Biochemistry, The Eck Institute for Global Health and The Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, Indiana 46556, .,the Department of Biochemistry and Molecular Biology, Indiana University School of Medicine-South Bend, South Bend, Indiana 46617
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45
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GC JB, Gerstman BS, Chapagain PP. Pi(4,5)P 2 Clustering by the Ebola Virus Matrix Protein VP40. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.1765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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46
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Bhattarai N, Gc JB, Gerstman BS, Stahelin RV, Chapagain PP. Plasma membrane association facilitates conformational changes in the Marburg virus protein VP40 dimer. RSC Adv 2017; 7:22741-22748. [PMID: 28580138 PMCID: PMC5436087 DOI: 10.1039/c7ra02940c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Accepted: 04/19/2017] [Indexed: 11/21/2022] Open
Abstract
The membrane binding interface of the Marburg virus protein mVP40 dimer differs from that of the Ebola virus eVP40 dimer but membrane binding allows conformational changes in mVP40 that makes it structurally similar to the eVP40 dimer.
Filovirus infections cause hemorrhagic fever in humans and non-human primates that often results in high fatality rates. The Marburg virus is a lipid-enveloped virus from the Filoviridae family and is closely related to the Ebola virus. The viral matrix layer underneath the lipid envelope is formed by the matrix protein VP40 (VP40), which is also involved in other functions during the viral life-cycle. As in the Ebola virus VP40 (eVP40), the recently determined X-ray crystal structure of the Marburg virus VP40 (mVP40) features loops containing cationic residues that form a lipid binding basic patch. However, the mVP40 basic patch is significantly flatter with a more extended surface than in eVP40, suggesting the possibility of differences in the plasma membrane interactions and phospholipid specificity between the VP40 dimers. In this paper, we report on molecular dynamics simulations that investigate the roles of various residues and lipid types in PM association as well as the conformational changes of the mVP40 dimer facilitated by membrane association. We compared the structural changes of the mVP40 dimer with the mVP40 dimer in both lipid free and membrane associated conditions. Despite the significant structural differences in the crystal structure, the Marburg VP40 dimer is found to adopt a configuration very similar to the Ebola VP40 dimer after associating with the membrane. This conformational rearrangement upon lipid binding allows Marburg VP40 to localize and stabilize at the membrane surface in a manner similar to the Ebola VP40 dimer. Consideration of the structural information in its lipid-interacting condition may be important in targeting mVP40 for novel drugs to inhibit viral budding from the plasma membrane.
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Affiliation(s)
- Nisha Bhattarai
- Department of Physics, Florida International University, Miami, FL 33199, USA.
| | - Jeevan B Gc
- Department of Physics, Florida International University, Miami, FL 33199, USA.
| | - Bernard S Gerstman
- Department of Physics, Florida International University, Miami, FL 33199, USA. .,Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Robert V Stahelin
- Department of Chemistry and Biochemistry, The Eck Institute for Global Health, The Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, IN 46556, USA.,Department of Biochemistry and Molecular Biology, Indiana University School of Medicine-South Bend, South Bend, IN 46617, USA
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, FL 33199, USA. .,Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
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47
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Gc JB, Gerstman BS, Stahelin RV, Chapagain PP. The Ebola virus protein VP40 hexamer enhances the clustering of PI(4,5)P 2 lipids in the plasma membrane. Phys Chem Chem Phys 2016; 18:28409-28417. [PMID: 27757455 PMCID: PMC5084917 DOI: 10.1039/c6cp03776c] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The Ebola virus is a lipid-enveloped virus that obtains its lipid coat from the plasma membrane of the host cell it infects during the budding process. The Ebola virus protein VP40 localizes to the inner leaflet of the plasma membrane and forms the viral matrix, which provides the major structure for the Ebola virus particles. VP40 is initially a dimer that rearranges to a hexameric structure that mediates budding. VP40 hexamers and larger filaments have been shown to be stabilized by PI(4,5)P2 in the plasma membrane inner leaflet. Reduction in the plasma membrane levels of PI(4,5)P2 significantly reduce formation of VP40 oligomers and virus-like particles. We investigated the lipid-protein interactions in VP40 hexamers at the plasma membrane. We quantified lipid-lipid self-clustering by calculating the fractional interaction matrix and found that the VP40 hexamer significantly enhances the PI(4,5)P2 clustering. The radial pair distribution functions suggest a strong interaction between PI(4,5)P2 and the VP40 hexamer. The cationic Lys side chains are found to mediate the PIP2 clustering around the protein, with cholesterol filling the space between the interacting PIP2 molecules. These computational studies support recent experimental data and provide new insights into the mechanisms by which VP40 assembles at the plasma membrane inner leaflet, alters membrane curvature, and forms new virus-like particles.
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Affiliation(s)
- Jeevan B Gc
- Department of Physics, Florida International University, Miami, FL 33199, USA.
| | - Bernard S Gerstman
- Department of Physics, Florida International University, Miami, FL 33199, USA. and Biomolecular Science Institute, Florida International University, Miami, FL 33199, USA
| | - Robert V Stahelin
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine-South Bend, South Bend, IN 46617, USA and Department of Chemistry and Biochemistry, The Eck Institute for Global Health, and the Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, FL 33199, USA. and Biomolecular Science Institute, Florida International University, Miami, FL 33199, USA
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48
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Garabedian A, Butcher D, Lippens JL, Miksovska J, Chapagain PP, Fabris D, Ridgeway ME, Park MA, Fernandez-Lima F. Structures of the kinetically trapped i-motif DNA intermediates. Phys Chem Chem Phys 2016; 18:26691-26702. [PMID: 27711445 PMCID: PMC5652045 DOI: 10.1039/c6cp04418b] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In the present work, the conformational dynamics and folding pathways of i-motif DNA were studied in solution and in the gas-phase as a function of the solution pH conditions using circular dichroism (CD), photoacoustic calorimetry analysis (PAC), trapped ion mobility spectrometry-mass spectrometry (TIMS-MS), and molecular dynamics (MD). Solution studies showed at thermodynamic equilibrium the existence of a two-state folding mechanism, whereas during the pH = 7.0 → 4.5 transition a fast and slow phase (ΔHfast + ΔHslow = 43 ± 7 kcal mol-1) with a volume change associated with the formation of hemiprotonated cytosine base pairs and concomitant collapse of the i-motif oligonucleotide into a compact conformation were observed. TIMS-MS experiments showed that gas-phase, kinetically trapped i-motif DNA intermediates produced by nanoESI are preserved, with relative abundances depending on the solution pH conditions. In particular, a folded i-motif DNA structure was observed in nanoESI-TIMS-MS for low charge states in both positive and negative ion mode (e.g., z = ±3 to ±5) at low pH conditions. As solution pH increases, the cytosine neutralization leads to the loss of cytosine-cytosine+ (C·CH+) base pairing in the CCC strands and in those conditions we observe partially unfolded i-motif DNA conformations in nanoESI-TIMS-MS for higher charge states (e.g., z = -6 to -9). Collisional induced activation prior to TIMS-MS showed the existence of multiple local free energy minima, associated with the i-motif DNA unfolding at z = -6 charge state. For the first time, candidate gas-phase structures are proposed based on mobility measurements of the i-motif DNA unfolding pathway. Moreover, the inspection of partially unfolded i-motif DNA structures (z = -7 and z = -8 charge states) showed that the presence of inner cations may or may not induce conformational changes in the gas-phase. For example, incorporation of ammonium adducts does not lead to major conformational changes while sodium adducts may lead to the formation of sodium mediated bonds between two negatively charged sides inducing the stabilization towards more compact structures in new local, free energy minima in the gas-phase.
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Affiliation(s)
- Alyssa Garabedian
- Department of Chemistry and Biochemistry, Florida International University, Miami, USA.
| | - David Butcher
- Department of Chemistry and Biochemistry, Florida International University, Miami, USA.
| | | | - Jaroslava Miksovska
- Department of Chemistry and Biochemistry, Florida International University, Miami, USA. and Biomolecular Science Institute, Florida International University, Miami, USA
| | - Prem P Chapagain
- Biomolecular Science Institute, Florida International University, Miami, USA and Department of Physics, Florida International University, Miami, USA
| | | | | | - Melvin A Park
- Bruker Daltonics Inc., Billerica, Massachusetts, USA
| | - Francisco Fernandez-Lima
- Department of Chemistry and Biochemistry, Florida International University, Miami, USA. and Biomolecular Science Institute, Florida International University, Miami, USA
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49
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Tiwari PB, Chapagain PP, Banda S, Darici Y, Üren A, Tse-Dinh YC. Characterization of molecular interactions between Escherichia coli RNA polymerase and topoisomerase I by molecular simulations. FEBS Lett 2016; 590:2844-51. [PMID: 27448274 DOI: 10.1002/1873-3468.12321] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 07/11/2016] [Accepted: 07/13/2016] [Indexed: 12/13/2022]
Abstract
Escherichia coli topoisomerase I (EctopoI), a type IA DNA topoisomerase, relaxes the negative DNA supercoiling generated by RNA polymerase (RNAP) during transcription elongation. Due to the lack of structural information on the complex, the exact nature of the RNAP-EctopoI interactions remains unresolved. Herein, we report for the first time, the structure-based modeling of the RNAP-EctopoI interactions using computational methods. Our results predict that the salt bridge as well as hydrogen bond interactions are responsible for the formation and stabilization of the RNAP-EctopoI complex. Our investigations provide molecular insights for understanding how EctopoI interacts with RNAP, a critical step for preventing hypernegative DNA supercoiling during transcription.
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Affiliation(s)
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, FL, USA.,Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Srikanth Banda
- Biomolecular Sciences Institute, Florida International University, Miami, FL, USA.,Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA
| | - Yesim Darici
- Department of Physics, Florida International University, Miami, FL, USA
| | - Aykut Üren
- Department of Oncology, Georgetown University, Washington, DC, USA
| | - Yuk-Ching Tse-Dinh
- Biomolecular Sciences Institute, Florida International University, Miami, FL, USA.,Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA
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50
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Konold PE, Yoon E, Lee J, Allen S, Chapagain PP, Gerstman BS, Regmi CK, Piatketvich KD, Verkhusha VV, Joo T, Jimenez R. Fluorescence from Multiple Chromophore Hydrogen-Bonding States in the Far-Red Protein TagRFP675. J Phys Chem Lett 2016; 7:3046-51. [PMID: 27447848 PMCID: PMC5004773 DOI: 10.1021/acs.jpclett.6b01172] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Far-red fluorescent proteins are critical for in vivo imaging applications, but the relative importance of structure versus dynamics in generating large Stokes-shifted emission is unclear. The unusually red-shifted emission of TagRFP675, a derivative of mKate, has been attributed to the multiple hydrogen bonds with the chromophore N-acylimine carbonyl. We characterized TagRFP675 and point mutants designed to perturb these hydrogen bonds with spectrally resolved transient grating and time-resolved fluorescence (TRF) spectroscopies supported by molecular dynamics simulations. TRF results for TagRFP675 and the mKate/M41Q variant show picosecond time scale red-shifts followed by nanosecond time blue-shifts. Global analysis of the TRF spectra reveals spectrally distinct emitting states that do not interconvert during the S1 lifetime. These dynamics originate from photoexcitation of a mixed ground-state population of acylimine hydrogen bond conformers. Strategically tuning the chromophore environment in TagRFP675 might stabilize the most red-shifted conformation and result in a variant with a larger Stokes shift.
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Affiliation(s)
- Patrick E. Konold
- JILA, University of Colorado and NIST, Boulder, CO 80309
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, CO 80309
| | - Eunjin Yoon
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, South Korea 790-784
| | - Junghwa Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, South Korea 790-784
| | - Samantha Allen
- JILA, University of Colorado and NIST, Boulder, CO 80309
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, CO 80309
| | - Prem P. Chapagain
- Department of Physics, Florida International University, Miami, FL 33199
| | | | - Chola K. Regmi
- Department of Physics, Florida International University, Miami, FL 33199
- Department of Physics, Virginia Tech, Blacksburg, VA 24061
| | - Kiryl D. Piatketvich
- Massachusetts Institute of Technology Media Lab, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Vladislav V. Verkhusha
- Department of Anatomy & Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Taiha Joo
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, South Korea 790-784
| | - Ralph Jimenez
- JILA, University of Colorado and NIST, Boulder, CO 80309
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, CO 80309
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