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Bao Y, Cao X, Landick R. RNA polymerase SI3 domain modulates global transcriptional pausing and pause-site fluctuations. Nucleic Acids Res 2024; 52:4556-4574. [PMID: 38554114 PMCID: PMC11077087 DOI: 10.1093/nar/gkae209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 03/03/2024] [Accepted: 03/26/2024] [Indexed: 04/01/2024] Open
Abstract
Transcriptional pausing aids gene regulation by cellular RNA polymerases (RNAPs). A surface-exposed domain inserted into the catalytic trigger loop (TL) of Escherichia coli RNAP, called SI3, modulates pausing and is essential for growth. Here we describe a viable E. coli strain lacking SI3 enabled by a suppressor TL substitution (β'Ala941→Thr; ΔSI3*). ΔSI3* increased transcription rate in vitro relative to ΔSI3, possibly explaining its viability, but retained both positive and negative effects of ΔSI3 on pausing. ΔSI3* inhibited pauses stabilized by nascent RNA structures (pause hairpins; PHs) but enhanced other pauses. Using NET-seq, we found that ΔSI3*-enhanced pauses resemble the consensus elemental pause sequence whereas sequences at ΔSI3*-suppressed pauses, which exhibited greater association with PHs, were more divergent. ΔSI3*-suppressed pauses also were associated with apparent pausing one nucleotide upstream from the consensus sequence, often generating tandem pause sites. These '-2 pauses' were stimulated by pyrophosphate in vitro and by addition of apyrase to degrade residual NTPs during NET-seq sample processing. We propose that some pauses are readily reversible by pyrophosphorolysis or single-nucleotide cleavage. Our results document multiple ways that SI3 modulates pausing in vivo and may explain discrepancies in consensus pause sequences in some NET-seq studies.
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Affiliation(s)
- Yu Bao
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Xinyun Cao
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
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2
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Lee KH, Shi L. Unraveling Activation-Related Rearrangements and Intrinsic Divergence from Ligand-Specific Conformational Changes of the Dopamine D3 and D2 Receptors. J Chem Inf Model 2024; 64:1778-1793. [PMID: 38454785 DOI: 10.1021/acs.jcim.3c01956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
Effective rational drug discovery hinges on understanding the functional states of the target protein and distinguishing it from homologues. However, for the G protein coupled receptors, both activation-related conformational changes (ACCs) and intrinsic divergence among receptors can be misled or obscured by ligand-specific conformational changes (LCCs). Here, we unraveled ACCs and intrinsic divergence from LCCs of the dopamine D3 and D2 receptors (D3R and D2R), by analyzing their experimentally determined structures and the molecular dynamics (MD) simulation results of the receptors bound with various ligands. In addition to the ACCs common to other aminergic receptors, we revealed unique ACCs for these two receptors, including the extracellular portion of TM5 (TM5e) and TM6e shifting away from TM2e and TM3e, with a subtle rotation of TM5e. In identifying intrinsic divergence, we found more outward tilting of TM6e in the D2R compared to the D3R in both the experimental structures and simulations bound with ligands in different scaffolds. However, this difference was drastically reduced in the simulations bound with nonselective agonist quinpirole, suggesting a misleading effect of LCCs. Further, in the quinpirole-bound simulations, TM1 showed a greater disparity between these receptors, indicating that LCCs may also obscure intrinsic divergence. Importantly, our MD simulations revealed divergence in the dynamics of these receptors. Specifically, the D2R exhibited heightened flexibility compared to the D3R in the extracellular loops and TMs 5e, 6e, and 7e, associated with its greater ligand binding site plasticity. Our results lay the groundwork for crafting ligands specifically targeting the D2R and D3R with more precise pharmacological profiles.
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Affiliation(s)
- Kuo Hao Lee
- Computational Chemistry and Molecular Biophysics Section, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics Section, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, United States
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3
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Stevens-Sostre WA, Flores-Aldama L, Bustos D, Li J, Morais-Cabral JH, Delemotte L, Robertson GA. An intracellular hydrophobic nexus critical for hERG1 channel slow deactivation. Biophys J 2024:S0006-3495(24)00026-2. [PMID: 38219015 DOI: 10.1016/j.bpj.2024.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/17/2023] [Accepted: 01/09/2024] [Indexed: 01/15/2024] Open
Abstract
Slow deactivation is a critical property of voltage-gated K+ channels encoded by the human Ether-à-go-go-Related Gene 1 (hERG). hERG1 channel deactivation is modulated by interactions between intracellular N-terminal Per-Arnt-Sim (PAS) and C-terminal cyclic nucleotide-binding homology (CNBh) domains. The PAS domain is multipartite, comprising a globular domain (gPAS; residues 26-135) and an N-terminal PAS-cap that is further subdivided into an initial unstructured "tip" (residues 1-12) and an amphipathic α-helical region (residues 13-25). Although the PAS-cap tip has long been considered the effector of slow deactivation, how its position near the gating machinery is controlled has not been elucidated. Here, we show that a triad of hydrophobic interactions among the gPAS, PAS-cap α helix, and the CNBh domains is required to support slow deactivation in hERG1. The primary sequence of this "hydrophobic nexus" is highly conserved among mammalian ERG channels but shows key differences to fast-deactivating Ether-à-go-go 1 (EAG1) channels. Combining sequence analysis, structure-directed mutagenesis, electrophysiology, and molecular dynamics simulations, we demonstrate that polar serine substitutions uncover an intermediate deactivation mode that is also mimicked by deletion of the PAS-cap α helix. Molecular dynamics simulation analyses of the serine-substituted channels show an increase in distance among the residues of the hydrophobic nexus, a rotation of the intracellular gating ring, and a retraction of the PAS-cap tip from its receptor site near the voltage sensor domain and channel gate. These findings provide compelling evidence that the hydrophobic nexus coordinates the respective components of the intracellular gating ring and positions the PAS-cap tip to control hERG1 deactivation gating.
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Affiliation(s)
- Whitney A Stevens-Sostre
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Lisandra Flores-Aldama
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Daniel Bustos
- Centro de Investigación de Estudios Avanzados Del Maule (CIEAM), Vicerrectoría de Investigación y Postgrado, Universidad Católica Del Maule, Talca, Chile; Laboratorio de Bioinformática y Química Computacional (LBQC), Departamento de Medicina Traslacional, Facultad de Medicina, Universidad Católica Del Maule, Talca, Chile
| | - Jin Li
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - João H Morais-Cabral
- Instituto de Investigação e Inovação Em Saude da Universidade Do Porto (i3S); Instituto de Biologia Molecular e Celular, Universidade Do Porto, Porto, Portugal
| | - Lucie Delemotte
- KTH Royal Institute of Technology, Science for Life Laboratory, Stockholm, Sweden
| | - Gail A Robertson
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
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4
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Lee KH, Shi L. Unraveling activation-related rearrangements and intrinsic divergence from ligand-induced conformational changes of the dopamine D3 and D2 receptors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.11.566699. [PMID: 38014309 PMCID: PMC10680602 DOI: 10.1101/2023.11.11.566699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Effective rational drug discovery targeting a specific protein hinges on understanding their functional states and distinguishing it from homologs. However, for the G protein coupled receptors, both the activation-related conformational changes (ACCs) and the intrinsic divergence among receptors can be misled or obscured by ligand-induced conformational changes (LCCs). Here, we unraveled ACCs and intrinsic divergence from LCCs of the dopamine D3 and D2 receptors (D3R and D2R), by analyzing their experimentally determined structures and the molecular dynamics simulation results of the receptors bound with different ligands. In addition to the ACCs common to other aminergic receptors, we revealed unique ACCs for these two receptors including TM5e and TM6e shifting away from TM2e and TM3e, with a subtle rotation of TM5e. In identifying intrinsic divergence, we found pronounced outward tilting of TM6e in the D2R compared to the D3R in both experimental structures and simulations with ligands in different scaffolds. This tilting was drastically reduced in the simulations of the receptors bound with nonselective full agonist quinpirole, suggesting a misleading impact of LCCs. Further, in the quinpirole-bound simulations, TM1 showed a greater disparity between these receptors, indicating that LCCs may obscure intrinsic divergence. In addition, our analysis showed that the impact of the nonconserved TM1 propagated to conserved Trp7.40 and Glu2.65, both are ligand binding residues. We also found that the D2R exhibited heightened flexibility compared to the D3R in the extracellular portions of TMs 5, 6, and 7, potentially associated with its greater ligand binding site plasticity. Our results lay the groundwork for crafting ligands specifically targeting D2R or D3R with more precise pharmacological profiles.
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Affiliation(s)
- Kuo Hao Lee
- Computational Chemistry and Molecular Biophysics Section, National Institute on Drug Abuse – Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics Section, National Institute on Drug Abuse – Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
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5
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Lee KH, Manning JJ, Javitch J, Shi L. A Novel "Activation Switch" Motif Common to All Aminergic Receptors. J Chem Inf Model 2023; 63:5001-5017. [PMID: 37540602 PMCID: PMC10695015 DOI: 10.1021/acs.jcim.3c00732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/06/2023]
Abstract
Aminergic receptors are G protein-coupled receptors (GPCRs) that transduce signals from small endogenous biogenic amines to regulate intracellular signaling pathways. Agonist binding in the ligand binding pocket on the extracellular side opens and prepares a cavity on the intracellular face of the receptors to interact with and activate G proteins and β-arrestins. Here, by reviewing and analyzing all available aminergic receptor structures, we seek to identify activation-related conformational changes that are independent of the specific scaffold of the bound agonist, which we define as "activation conformational changes" (ACCs). While some common intracellular ACCs have been well-documented, identifying common extracellular ACCs, including those in the ligand binding pocket, is complicated by local adjustments to different ligand scaffolds. Our analysis shows no common ACCs at the extracellular ends of the transmembrane helices. Furthermore, the restricted access to the ligand binding pocket identified previously in some receptors is not universal. Notably, the Trp6.48 toggle switch and the Pro5.50-Ile3.40-Phe6.44 (PIF) motif at the bottom of the ligand binding pocket have previously been proposed to mediate the conformational consequences of ligand binding to the intracellular side of the receptors. Our analysis shows that common ACCs in the ligand binding pocket are associated with the PIF motif and nearby residues, including Trp6.48, but fails to support a shared rotamer toggle associated with activation. However, we identify two common rearrangements between the extracellular and middle subsegments, and propose a novel "activation switch" motif common to all aminergic receptors. This motif includes the middle subsegments of transmembrane helices 3, 5, and 6 and integrates both the PIF motif and Trp6.48.
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Affiliation(s)
- Kuo Hao Lee
- Computational Chemistry and Molecular Biophysics Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse – Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | - Jamie J. Manning
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
- Department of Psychiatry, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Jonathan Javitch
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
- Department of Psychiatry, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse – Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
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6
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Sethupathi M, Thulasinathan B, Sengottuvelan N, Ponnuchamy K, Perdih F, Alagarsamy A, Karthikeyan M. Macrocyclic "tet a"-Derived Cobalt(III) Complex with a N, N'-Disubstituted Hexadentate Ligand: Crystal Structure, Photonuclease Activity, and as a Photosensitizer. ACS OMEGA 2022; 7:669-682. [PMID: 35036733 PMCID: PMC8756598 DOI: 10.1021/acsomega.1c05306] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
A cobalt(III) complex, [Co(L)]Cl (complex 1, where L = 1,8-[N,N-bis{(3-formyl-2-hydroxy-5-methyl)benzyl}]-1,4,8,11-tetraaza-5,5,7,12,12,14-hexamethylcyclotetradecane) with distorted octahedral geometry has been synthesized and characterized using various spectroscopic techniques. The structure of the ligand has remarkably rich hydrogen intermolecular interactions such as H···H, H···C/C···H, and H···O/O···H that vary with the presence of the metal ion, and the structure of complex 1 has Cl···H interactions; this result has been proved by Hirshfeld surface and two-dimensional (2D) fingerprint maps analyses. The complex exhibits a quasi-reversible Co(III)/Co(II) redox couple with E 1/2 = -0.76 V. Calf thymus DNA (CT DNA) binding abilities of the ligand and complex 1 were confirmed by spectroscopic and electrochemical analyses. According to absorption studies, the ligand and complex 1 bind to CT DNA via intercalative binding mode, with intrinsic binding strengths of 1.41 × 103 and 8.64 × 103 M-1, respectively. A gel electrophoresis assay shows that complex 1 promotes the pUC19 DNA cleavage under dark and light irradiation conditions. Complex 1 has superior antimicrobial activity than the ligand. The cytotoxicity of complex 1 was tested against MDA-MB-231 breast cancer cells with values of IC50 of 1.369 μg mL-1 in the dark and 0.9034 μg mL-1 after light irradiation. Besides, cell morphological studies confirmed the morphological changes with AO/EB dual staining, reactive oxygen species (ROS) staining, mitochondria staining, and Hoechst staining on MDA-MB-231 cancer cells by fluorescence microscopy. Complex 1 was found to be a potent antiproliferative agent against MDA-MB-231 cells, and it can induce mitochondrial-mediated and caspase-dependent apoptosis with activation of downregulated caspases. The biotoxicity assay of complex 1 on the development of Artemia nauplii was evaluated at an IC50 value of 200 μg mL-1 and with excellent biocompatibility.
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Affiliation(s)
- Murugan Sethupathi
- Department
of Industrial Chemistry, Alagappa University, Karaikudi 630003, Tamil Nadu, India
| | | | - Nallathambi Sengottuvelan
- Department
of Industrial Chemistry, Alagappa University, Karaikudi 630003, Tamil Nadu, India
- Department
of Chemistry (DDE), Alagappa University, Karaikudi 630003, Tamil Nadu, India
| | - Kumar Ponnuchamy
- Food
Chemistry and Molecular Cancer Biology Laboratory, Department of Animal
Health and Management, Alagappa University, Karaikudi 630003, Tamil Nadu, India
| | - Franc Perdih
- Faculty
of Chemistry and Chemical Technology, University
of Ljubljana, 1000 Ljubljana, Slovenia
| | - Arun Alagarsamy
- Department
of Microbiology, Alagappa University, Karaikudi 630003, Tamil Nadu, India
| | - Muthusamy Karthikeyan
- Pharmacogenomics
and Computational Biology Laboratory, Department of Bioinformatics, Alagappa University, Karaikudi 630004, Tamil
Nadu, India
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7
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Modeling SARS-CoV-2 spike/ACE2 protein-protein interactions for predicting the binding affinity of new spike variants for ACE2, and novel ACE2 structurally related human protein targets, for COVID-19 handling in the 3PM context. EPMA J 2022; 13:149-175. [PMID: 35013687 PMCID: PMC8732965 DOI: 10.1007/s13167-021-00267-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/04/2021] [Indexed: 12/12/2022]
Abstract
Aims The rapid spread of new SARS-CoV-2 variants has highlighted the crucial role played in the infection by mutations occurring at the SARS-CoV-2 spike receptor binding domain (RBD) in the interactions with the human ACE2 receptor. In this context, it urgently needs to develop new rapid tools for quickly predicting the affinity of ACE2 for the SARS-CoV-2 spike RBD protein variants to be used with the ongoing SARS-CoV-2 genomic sequencing activities in the clinics, aiming to gain clues about the transmissibility and virulence of new variants, to prevent new outbreaks and to quickly estimate the severity of the disease in the context of the 3PM. Methods In our study, we used a computational pipeline for calculating the interaction energies at the SARS-CoV-2 spike RBD/ACE2 protein–protein interface for a selected group of characterized infectious variants of concern/interest (VoC/VoI). By using our pipeline, we built 3D comparative models of the SARS-CoV-2 spike RBD/ACE2 protein complexes for the VoC B.1.1.7-United Kingdom (carrying the mutations of concern/interest N501Y, S494P, E484K at the RBD), P.1-Japan/Brazil (RBD mutations: K417T, E484K, N501Y), B.1.351-South Africa (RBD mutations: K417N, E484K, N501Y), B.1.427/B.1.429-California (RBD mutations: L452R), the B.1.141 (RBD mutations: N439K), and the recent B.1.617.1-India (RBD mutations: L452R; E484Q) and the B.1.620 (RBD mutations: S477N; E484K). Then, we used the obtained 3D comparative models of the SARS-CoV-2 spike RBD/ACE2 protein complexes for predicting the interaction energies at the protein–protein interface. Results Along SARS-CoV-2 mutation database screening and mutation localization analysis, it was ascertained that the most dangerous mutations at VoC/VoI spike proteins are located mainly at three regions of the SARS-CoV-2 spike “boat-shaped” receptor binding motif, on the RBD domain. Notably, the P.1 Japan/Brazil variant present three mutations, K417T, E484K, N501Y, located along the entire receptor binding motif, which apparently determines the highest interaction energy at the SARS-CoV-2 spike RBD/ACE2 protein–protein interface, among those calculated. Conversely, it was also observed that the replacement of a single acidic/hydrophilic residue with a basic residue (E484K or N439K) at the “stern” or “bow” regions, of the boat-shaped receptor binding motif on the RBD, appears to determine an interaction energy with ACE2 receptor higher than that observed with single mutations occurring at the “hull” region or with other multiple mutants. In addition, our pipeline allowed searching for ACE2 structurally related proteins, i.e., THOP1 and NLN, which deserve to be investigated for their possible involvement in interactions with the SARS-CoV-2 spike protein, in those tissues showing a low expression of ACE2, or as a novel receptor for future spike variants. A freely available web-tool for the in silico calculation of the interaction energy at the SARS-CoV-2 spike RBD/ACE2 protein–protein interface, starting from the sequences of the investigated spike and/or ACE2 variants, was made available for the scientific community at: https://www.mitoairm.it/covid19affinities. Conclusion In the context of the PPPM/3PM, the employment of the described pipeline through the provided webservice, together with the ongoing SARS-CoV-2 genomic sequencing, would help to predict the transmissibility of new variants sequenced from future patients, depending on SARS-CoV-2 genomic sequencing activities and on the specific amino acid replacement and/or on its location on the SARS-CoV-2 spike RBD, to put in play all the possible counteractions for preventing the most deleterious scenarios of new outbreaks, taking into consideration that a greater transmissibility has not to be necessarily related to a more severe manifestation of the disease. Supplementary Information The online version contains supplementary material available at 10.1007/s13167-021-00267-w.
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Mitsumoto M, Sugaya K, Kazama K, Nakano R, Kosugi T, Murata T, Koga N. State-Targeting Stabilization of Adenosine A 2A Receptor by Fusing a Custom-Made De Novo Designed α-Helical Protein. Int J Mol Sci 2021; 22:12906. [PMID: 34884716 PMCID: PMC8657880 DOI: 10.3390/ijms222312906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/19/2021] [Accepted: 11/23/2021] [Indexed: 01/03/2023] Open
Abstract
G-protein coupled receptors (GPCRs) are known for their low stability and large conformational changes upon transitions between multiple states. A widely used method for stabilizing these receptors is to make chimeric receptors by fusing soluble proteins (i.e., fusion partner proteins) into the intracellular loop 3 (ICL3) connecting the transmembrane helices 5 and 6 (TM5 and TM6). However, this fusion approach requires experimental trial and error to identify appropriate soluble proteins, residue positions, and linker lengths for making the fusion. Moreover, this approach has not provided state-targeting stabilization of GPCRs. Here, to rationally stabilize a class A GPCR, adenosine A2A receptor (A2AR) in a target state, we carried out the custom-made de novo design of α-helical fusion partner proteins, which can fix the conformation of TM5 and TM6 to that in an inactive state of A2AR through straight helical connections without any kinks or intervening loops. The chimeric A2AR fused with one of the designs (FiX1) exhibited increased thermal stability. Moreover, compared with the wild type, the binding affinity of the chimera against the agonist NECA was significantly decreased, whereas that against the inverse agonist ZM241385 was similar, indicating that the inactive state was selectively stabilized. Our strategy contributes to the rational state-targeting stabilization of GPCRs.
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Affiliation(s)
- Masaya Mitsumoto
- Department of Structural Molecular Science, School of Physical Sciences, SOKENDAI, The Graduate University for Advanced Studies, Shonan Village, Hayama 240-0193, Kanagawa, Japan; (M.M.); (T.K.)
- Research Center of Integrative Molecular Systems, Institute for Molecular Science (IMS), National Institutes of Natural Sciences (NINS), Okazaki 444-8585, Aichi, Japan
| | - Kanna Sugaya
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan; (K.S.); (K.K.); (R.N.)
| | - Kazuki Kazama
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan; (K.S.); (K.K.); (R.N.)
| | - Ryosuke Nakano
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan; (K.S.); (K.K.); (R.N.)
| | - Takahiro Kosugi
- Department of Structural Molecular Science, School of Physical Sciences, SOKENDAI, The Graduate University for Advanced Studies, Shonan Village, Hayama 240-0193, Kanagawa, Japan; (M.M.); (T.K.)
- Research Center of Integrative Molecular Systems, Institute for Molecular Science (IMS), National Institutes of Natural Sciences (NINS), Okazaki 444-8585, Aichi, Japan
- Protein Design Group, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences (NINS), Okazaki 444-8585, Aichi, Japan
| | - Takeshi Murata
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan; (K.S.); (K.K.); (R.N.)
- Membrane Protein Research Center, Chiba University, Chiba 263-8522, Japan
| | - Nobuyasu Koga
- Department of Structural Molecular Science, School of Physical Sciences, SOKENDAI, The Graduate University for Advanced Studies, Shonan Village, Hayama 240-0193, Kanagawa, Japan; (M.M.); (T.K.)
- Research Center of Integrative Molecular Systems, Institute for Molecular Science (IMS), National Institutes of Natural Sciences (NINS), Okazaki 444-8585, Aichi, Japan
- Protein Design Group, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences (NINS), Okazaki 444-8585, Aichi, Japan
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9
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A GX 2GX 3G motif facilitates acyl chain sequestration by Saccharomyces cerevisiae acyl carrier protein. J Biol Chem 2021; 297:101394. [PMID: 34767798 PMCID: PMC8683515 DOI: 10.1016/j.jbc.2021.101394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 11/03/2021] [Accepted: 11/05/2021] [Indexed: 11/21/2022] Open
Abstract
Saccharomyces cerevisiae acyl carrier protein (ScACP) is a component of the large fungal fatty acid synthase I (FAS I) complex. ScACP comprises two subdomains: a conserved ACP domain that shares extensive structural homology with other ACPs and a unique structural domain. Unlike the metazoan type I ACP that does not sequester the acyl chain, ScACP can partially sequester the growing acyl chain within its hydrophobic core by a mechanism that remains elusive. Our studies on the acyl-ScACP intermediates disclose a unique 188GX2GX3G195 sequence in helix II important for ACP function. Complete loss of sequestration was observed upon mutation of the three glycines in this sequence to valine (G188V/G191V/G195V), while G191V and G188V/G191V double mutants displayed a faster rate of acyl chain hydrolysis. Likewise, mutation of Thr216 to Ala altered the size of the hydrophobic cavity, resulting in loss of C12- chain sequestration. Combining NMR studies with insights from the crystal structure, we show that three glycines in helix II and a threonine in helix IV favor conformational change, which in turn generate space for acyl chain sequestration. Furthermore, we identified the primary hydrophobic cavity of ScACP, present between the carboxyl end of helix II and IV. The opening of the cavity lies between the second and third turns of helix II and loop II. Overall, the study highlights a novel role of the GX2GX3G motif in regulating acyl chain sequestration, vital for ScACP function.
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10
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Cryo-EM structure of the mature and infective Mayaro virus at 4.4 Å resolution reveals features of arthritogenic alphaviruses. Nat Commun 2021; 12:3038. [PMID: 34031424 PMCID: PMC8144435 DOI: 10.1038/s41467-021-23400-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 04/27/2021] [Indexed: 12/19/2022] Open
Abstract
Mayaro virus (MAYV) is an emerging arbovirus of the Americas that may cause a debilitating arthritogenic disease. The biology of MAYV is not fully understood and largely inferred from related arthritogenic alphaviruses. Here, we present the structure of MAYV at 4.4 Å resolution, obtained from a preparation of mature, infective virions. MAYV presents typical alphavirus features and organization. Interactions between viral proteins that lead to particle formation are described together with a hydrophobic pocket formed between E1 and E2 spike proteins and conformational epitopes specific of MAYV. We also describe MAYV glycosylation residues in E1 and E2 that may affect MXRA8 host receptor binding, and a molecular “handshake” between MAYV spikes formed by N262 glycosylation in adjacent E2 proteins. The structure of MAYV is suggestive of structural and functional complexity among alphaviruses, which may be targeted for specificity or antiviral activity. Mayaro virus (MAYV) is an emerging arbovirus in Central and South America that is transmitted by mosquitoes and causes arthritogenic disease. Here, the authors present the 4.4 Å resolution cryo-EM structure of MAYV and describe specific features of the virus, which could be exploited for the design of MAYV-specific diagnostics and therapeutics.
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11
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Mapping temperature-dependent conformational change in the voltage-sensing domain of an engineered heat-activated K + channel. Proc Natl Acad Sci U S A 2021; 118:2017280118. [PMID: 33782120 DOI: 10.1073/pnas.2017280118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Temperature-dependent regulation of ion channel activity is critical for a variety of physiological processes ranging from immune response to perception of noxious stimuli. Our understanding of the structural mechanisms that underlie temperature sensing remains limited, in part due to the difficulty of combining high-resolution structural analysis with temperature stimulus. Here, we use NMR to compare the temperature-dependent behavior of Shaker potassium channel voltage sensor domain (WT-VSD) to its engineered temperature sensitive (TS-VSD) variant. Further insight into the molecular basis for temperature-dependent behavior is obtained by analyzing the experimental results together with molecular dynamics simulations. Our studies reveal that the overall secondary structure of the engineered TS-VSD is identical to the wild-type channels except for local changes in backbone torsion angles near the site of substitution (V369S and F370S). Remarkably however, these structural differences result in increased hydration of the voltage-sensing arginines and the S4-S5 linker helix in the TS-VSD at higher temperatures, in contrast to the WT-VSD. These findings highlight how subtle differences in the primary structure can result in large-scale changes in solvation and thereby confer increased temperature-dependent activity beyond that predicted by linear summation of solvation energies of individual substituents.
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Analysis of Sequence Divergence in Mammalian ABCGs Predicts a Structural Network of Residues That Underlies Functional Divergence. Int J Mol Sci 2021; 22:ijms22063012. [PMID: 33809494 PMCID: PMC8001107 DOI: 10.3390/ijms22063012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/08/2021] [Accepted: 03/12/2021] [Indexed: 12/17/2022] Open
Abstract
The five members of the mammalian G subfamily of ATP-binding cassette transporters differ greatly in their substrate specificity. Four members of the subfamily are important in lipid transport and the wide substrate specificity of one of the members, ABCG2, is of significance due to its role in multidrug resistance. To explore the origin of substrate selectivity in members 1, 2, 4, 5 and 8 of this subfamily, we have analysed the differences in conservation between members in a multiple sequence alignment of ABCG sequences from mammals. Mapping sets of residues with similar patterns of conservation onto the resolved 3D structure of ABCG2 reveals possible explanations for differences in function, via a connected network of residues from the cytoplasmic to transmembrane domains. In ABCG2, this network of residues may confer extra conformational flexibility, enabling it to transport a wider array of substrates.
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Verma N, Tao Y, Kraka E. Systematic Detection and Characterization of Hydrogen Bonding in Proteins via Local Vibrational Modes. J Phys Chem B 2021; 125:2551-2565. [DOI: 10.1021/acs.jpcb.0c11392] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Niraj Verma
- Department of Chemistry, Southern Methodist University, Dallas Texas United States
| | - Yunwen Tao
- Department of Chemistry, Southern Methodist University, Dallas Texas United States
| | - Elfi Kraka
- Department of Chemistry, Southern Methodist University, Dallas Texas United States
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Fang Z, Chen S, Manchanda Y, Bitsi S, Pickford P, David A, Shchepinova MM, Corrêa Jr IR, Hodson DJ, Broichhagen J, Tate EW, Reimann F, Salem V, Rutter GA, Tan T, Bloom SR, Tomas A, Jones B. Ligand-Specific Factors Influencing GLP-1 Receptor Post-Endocytic Trafficking and Degradation in Pancreatic Beta Cells. Int J Mol Sci 2020; 21:E8404. [PMID: 33182425 PMCID: PMC7664906 DOI: 10.3390/ijms21218404] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/01/2020] [Accepted: 11/02/2020] [Indexed: 12/30/2022] Open
Abstract
The glucagon-like peptide-1 receptor (GLP-1R) is an important regulator of blood glucose homeostasis. Ligand-specific differences in membrane trafficking of the GLP-1R influence its signalling properties and therapeutic potential in type 2 diabetes. Here, we have evaluated how different factors combine to control the post-endocytic trafficking of GLP-1R to recycling versus degradative pathways. Experiments were performed in primary islet cells, INS-1 832/3 clonal beta cells and HEK293 cells, using biorthogonal labelling of GLP-1R to determine its localisation and degradation after treatment with GLP-1, exendin-4 and several further GLP-1R agonist peptides. We also characterised the effect of a rare GLP1R coding variant, T149M, and the role of endosomal peptidase endothelin-converting enzyme-1 (ECE-1), in GLP1R trafficking. Our data reveal how treatment with GLP-1 versus exendin-4 is associated with preferential GLP-1R targeting towards a recycling pathway. GLP-1, but not exendin-4, is a substrate for ECE-1, and the resultant propensity to intra-endosomal degradation, in conjunction with differences in binding affinity, contributes to alterations in GLP-1R trafficking behaviours and degradation. The T149M GLP-1R variant shows reduced signalling and internalisation responses, which is likely to be due to disruption of the cytoplasmic region that couples to intracellular effectors. These observations provide insights into how ligand- and genotype-specific factors can influence GLP-1R trafficking.
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Affiliation(s)
- Zijian Fang
- Section of Endocrinology and Investigative Medicine, Imperial College London, London W12 0NN, UK; (Z.F.); (S.C.); (P.P.); (V.S.); (T.T.); (S.R.B.)
- Wellcome Trust–Medical Research Council Cambridge Stem Cell Institute and Department of Haematology, University of Cambridge, Cambridge CB2 0AW, UK
| | - Shiqian Chen
- Section of Endocrinology and Investigative Medicine, Imperial College London, London W12 0NN, UK; (Z.F.); (S.C.); (P.P.); (V.S.); (T.T.); (S.R.B.)
| | - Yusman Manchanda
- Section of Cell Biology and Functional Genomics, Imperial College London, London W12 0NN, UK; (Y.M.); (S.B.); (G.A.R.)
| | - Stavroula Bitsi
- Section of Cell Biology and Functional Genomics, Imperial College London, London W12 0NN, UK; (Y.M.); (S.B.); (G.A.R.)
| | - Philip Pickford
- Section of Endocrinology and Investigative Medicine, Imperial College London, London W12 0NN, UK; (Z.F.); (S.C.); (P.P.); (V.S.); (T.T.); (S.R.B.)
| | - Alessia David
- Centre for Bioinformatics and System Biology, Department of Life Sciences, Imperial College London, London SW7 2BX, UK;
| | - Maria M. Shchepinova
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, 80 Wood Lane, London W12 0BZ, UK; (M.M.S.); (E.W.T.)
| | | | - David J. Hodson
- Institute of Metabolism and Systems Research (IMSR), and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham B15 2TT, UK;
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK
| | - Johannes Broichhagen
- Department of Chemical Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany;
- Department of Chemical Biology, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
| | - Edward W. Tate
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, 80 Wood Lane, London W12 0BZ, UK; (M.M.S.); (E.W.T.)
| | - Frank Reimann
- Institute of Metabolic Science & MRC Metabolic Diseases Unit, University of Cambridge, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 0QQ, UK;
| | - Victoria Salem
- Section of Endocrinology and Investigative Medicine, Imperial College London, London W12 0NN, UK; (Z.F.); (S.C.); (P.P.); (V.S.); (T.T.); (S.R.B.)
| | - Guy A. Rutter
- Section of Cell Biology and Functional Genomics, Imperial College London, London W12 0NN, UK; (Y.M.); (S.B.); (G.A.R.)
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 639798, Singapore
| | - Tricia Tan
- Section of Endocrinology and Investigative Medicine, Imperial College London, London W12 0NN, UK; (Z.F.); (S.C.); (P.P.); (V.S.); (T.T.); (S.R.B.)
| | - Stephen R. Bloom
- Section of Endocrinology and Investigative Medicine, Imperial College London, London W12 0NN, UK; (Z.F.); (S.C.); (P.P.); (V.S.); (T.T.); (S.R.B.)
| | - Alejandra Tomas
- Section of Cell Biology and Functional Genomics, Imperial College London, London W12 0NN, UK; (Y.M.); (S.B.); (G.A.R.)
| | - Ben Jones
- Section of Endocrinology and Investigative Medicine, Imperial College London, London W12 0NN, UK; (Z.F.); (S.C.); (P.P.); (V.S.); (T.T.); (S.R.B.)
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Yan R, Zhou Q, Xu Z, Zhu G, Dong K, Zhorov BS, Chen M. Three sodium channel mutations from Aedes albopictus confer resistance to Type I, but not Type II pyrethroids. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 123:103411. [PMID: 32450204 DOI: 10.1016/j.ibmb.2020.103411] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/30/2020] [Accepted: 05/09/2020] [Indexed: 06/11/2023]
Abstract
Voltage-gated sodium channels are the major targets of several classes of insecticides, including pyrethroids. However, sensitivities of many insect pest species to pyrethroids have gradually decreased due to overuse in pest management programs. One major mechanism of pyrethroid resistance known as knockdown resistance (kdr) involves mutations in the sodium channel gene. Three new mutations in helix IIIS6 of sodium channel (I1532T and F1534S/L) are recently detected in several pyrethroid-resistant populations of Aedes albopictus. The roles of these mutations in pyrethroid resistance have not been functionally examined. We introduced mutations I1532T and F1534S/L alone or in combination into the pyrethroid-sensitive sodium channel AaNav1-1 from Aedes aegypti by site-directed mutagenesis and explored effects of these mutations on the channel gating and sensitivity to pyrethroids. No significant modifications in channel properties were detected, except for a slightly changed activation by F1534S and I1532T + F1534S. However, I1532T and F1534S/L substantially reduced the channel sensitivity to Type I pyrethroids, permethrin and bifenthrin, but not to two Type II pyrethroids, deltamethrin and cypermethrin. The double mutations did not increase the channel resistance to permethrin or bifenthrin. We have built a Nav1.4-based homology model of the AaNav1-1 channel and docked pyrethroids in the model to explain different sensitivities of the mutants to Type I and Type II pyrethroids. The results will assist in developing molecular markers for monitoring pest resistance to pyrethroids. They also provide new insight in the molecular basis of different action of Type I and Type II pyrethroids on sodium channels.
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Affiliation(s)
- Ru Yan
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Science, China Jiliang University, Hangzhou, 310018, China; Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, 310029, China
| | - Qiaoling Zhou
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, 310029, China
| | - Zhanyi Xu
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, 310029, China
| | - Guonian Zhu
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, 310029, China
| | - Ke Dong
- Department of Entomology, Genetics and Neuroscience Programs, Michigan State University, East Lansing, MI48824, USA
| | - Boris S Zhorov
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, L8N 3Z5, Canada; Sechenov Institute of Evolutionary Physiology & Biochemistry, Russian Academy of Sciences, St. Petersburg, 194223, Russia
| | - Mengli Chen
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Science, China Jiliang University, Hangzhou, 310018, China; Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, 310029, China.
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Isawi IH, Morales P, Sotudeh N, Hurst DP, Lynch DL, Reggio PH. GPR6 Structural Insights: Homology Model Construction and Docking Studies. Molecules 2020; 25:molecules25030725. [PMID: 32046081 PMCID: PMC7037797 DOI: 10.3390/molecules25030725] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 02/01/2020] [Accepted: 02/04/2020] [Indexed: 01/14/2023] Open
Abstract
GPR6 is an orphan G protein-coupled receptor that has been associated with the cannabinoid family because of its recognition of a sub-set of cannabinoid ligands. The high abundance of GPR6 in the central nervous system, along with high constitutive activity and a link to several neurodegenerative diseases make GPR6 a promising biological target. In fact, diverse research groups have demonstrated that GPR6 represents a possible target for the treatment of neurodegenerative disorders such as Parkinson's disease, Alzheimer's disease, and Huntington's disease. Several patents have claimed the use of a wide range of pyrazine derivatives as GPR6 inverse agonists for the treatment of Parkinson's disease symptoms and other dyskinesia syndromes. However, the full pharmacological importance of GPR6 has not yet been fully explored due to the lack of high potency, readily available ligands targeting GPR6. The long-term goal of the present study is to develop such ligands. In this paper, we describe our initial steps towards this goal. A human GPR6 homology model was constructed using a suite of computational techniques. This model permitted the identification of unique GPR6 structural features and the exploration of the GPR6 binding crevice. A subset of patented pyrazine analogs were docked in the resultant GPR6 inactive state model to validate the model, rationalize the structure-activity relationships from the reported patents and identify the key residues in the binding crevice for ligand recognition. We will take this structural knowledge into the next phase of GPR6 project, in which scaffold hopping will be used to design new GPR6 ligands.
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Affiliation(s)
- Israa H. Isawi
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412, USA; (I.H.I.); (D.P.H.); (D.L.L.)
| | - Paula Morales
- Instituto de Química Medica (IQM-CSIC), C/Juan de la Cierva 3, 28006 Madrid, Spain;
| | - Noori Sotudeh
- Department of Physiology and Biophysics, The State University of New York at Buffalo, Buffalo, NY 14260, USA;
| | - Dow P. Hurst
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412, USA; (I.H.I.); (D.P.H.); (D.L.L.)
| | - Diane L. Lynch
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412, USA; (I.H.I.); (D.P.H.); (D.L.L.)
| | - Patricia H. Reggio
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412, USA; (I.H.I.); (D.P.H.); (D.L.L.)
- Correspondence:
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Pérez-Benito L, Llinas del Torrent C, Pardo L, Tresadern G. The computational modeling of allosteric modulation of metabotropic glutamate receptors. FROM STRUCTURE TO CLINICAL DEVELOPMENT: ALLOSTERIC MODULATION OF G PROTEIN-COUPLED RECEPTORS 2020; 88:1-33. [DOI: 10.1016/bs.apha.2020.02.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Hammond K, Lewis H, Faruqui N, Russell C, Hoogenboom BW, Ryadnov MG. Helminth Defense Molecules as Design Templates for Membrane Active Antibiotics. ACS Infect Dis 2019; 5:1471-1479. [PMID: 31117348 DOI: 10.1021/acsinfecdis.9b00157] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A design template for membrane active antibiotics against microbial and tumor cells is described. The template is an amino acid sequence that combines the properties of helminth defense molecules, which are not cytolytic, with the properties of host-defense peptides, which disrupt microbial membranes. Like helminth defense molecules, the template folds into an amphipathic helix in both mammalian host and microbial phospholipid membranes. Unlike these molecules, the template exhibits antimicrobial and anticancer properties that are comparable to those of antimicrobial and anticancer antibiotics. The selective antibiotic activity of the template builds upon a functional synergy between three distinctive faces of the helix, which is in contrast to two faces of membrane-disrupting amphipathic structures. This synergy enables the template to adapt pore formation mechanisms according to the nature of the target membrane, inducing the lysis of microbial and tumor cells.
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Affiliation(s)
- Katharine Hammond
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom
- Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
- London Centre for Nanotechnology, University College London, Gordon Street, London WC1H 0AH, United Kingdom
| | - Helen Lewis
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom
| | - Nilofar Faruqui
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom
| | - Craig Russell
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom
| | - Bart W. Hoogenboom
- Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
- London Centre for Nanotechnology, University College London, Gordon Street, London WC1H 0AH, United Kingdom
| | - Maxim G. Ryadnov
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom
- Department of Physics, King’s College London, Strand Lane, London WC2R, United Kingdom
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Mayol E, Campillo M, Cordomí A, Olivella M. Inter-residue interactions in alpha-helical transmembrane proteins. Bioinformatics 2019; 35:2578-2584. [PMID: 30566615 DOI: 10.1093/bioinformatics/bty978] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 10/19/2018] [Accepted: 12/17/2018] [Indexed: 01/23/2023] Open
Abstract
MOTIVATION The number of available membrane protein structures has markedly increased in the last years and, in parallel, the reliability of the methods to detect transmembrane (TM) segments. In the present report, we characterized inter-residue interactions in α-helical membrane proteins using a dataset of 3462 TM helices from 430 proteins. This is by far the largest analysis published to date. RESULTS Our analysis of residue-residue interactions in TM segments of membrane proteins shows that almost all interactions involve aliphatic residues and Phe. There is lack of polar-polar, polar-charged and charged-charged interactions except for those between Thr or Ser sidechains and the backbone carbonyl of aliphatic and Phe residues. The results are discussed in the context of the preferences of amino acids to be in the protein core or exposed to the lipid bilayer and to occupy specific positions along the TM segment. Comparison to datasets of β-barrel membrane proteins and of α-helical globular proteins unveils the specific patterns of interactions and residue composition characteristic of α-helical membrane proteins that are the clue to understanding their structure. AVAILABILITY AND IMPLEMENTATION Results data and datasets used are available at http://lmc.uab.cat/TMalphaDB/interactions.php. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Eduardo Mayol
- Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Mercedes Campillo
- Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Arnau Cordomí
- Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Mireia Olivella
- Bioinformatics Area, School of International Studies, ESCI-UPF, Barcelona, Spain.,Bioinformatics and Medical Statistics Group, U Science Tech, Central University of Catalonia, Vic, Barcelona, Spain
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Bactericidal Disruption of Magnesium Metallostasis in Mycobacterium tuberculosis Is Counteracted by Mutations in the Metal Ion Transporter CorA. mBio 2019; 10:mBio.01405-19. [PMID: 31289182 PMCID: PMC6747715 DOI: 10.1128/mbio.01405-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Antimycobacterial agents might shorten the course of treatment by reducing the number of phenotypically tolerant bacteria if they could kill M. tuberculosis in diverse metabolic states. Here we report two chemically disparate classes of agents that kill M. tuberculosis both when it is replicating and when it is not. Under replicating conditions, the tricyclic 4-hydroxyquinolines and a barbituric acid analogue deplete intrabacterial magnesium as a mechanism of action, and for both compounds, mutations in CorA, a putative Mg2+/Co2+ transporter, conferred resistance to the compounds when M. tuberculosis was under replicating conditions but not under nonreplicating conditions, illustrating that a given compound can kill M. tuberculosis in different metabolic states by disparate mechanisms. Targeting magnesium metallostasis represents a previously undescribed antimycobacterial mode of action that might cripple M. tuberculosis in a Mg2+-deficient intraphagosomal environment of macrophages. A defining characteristic of treating tuberculosis is the need for prolonged administration of multiple drugs. This may be due in part to subpopulations of slowly replicating or nonreplicating Mycobacterium tuberculosis bacilli exhibiting phenotypic tolerance to most antibiotics in the standard treatment regimen. Confounding this problem is the increasing incidence of heritable multidrug-resistant M. tuberculosis. A search for new antimycobacterial chemical scaffolds that can kill phenotypically drug-tolerant mycobacteria uncovered tricyclic 4-hydroxyquinolines and a barbituric acid derivative with mycobactericidal activity against both replicating and nonreplicating M. tuberculosis. Both families of compounds depleted M. tuberculosis of intrabacterial magnesium. Complete or partial resistance to both chemotypes arose from mutations in the putative mycobacterial Mg2+/Co2+ ion channel, CorA. Excess extracellular Mg2+, but not other divalent cations, diminished the compounds’ cidality against replicating M. tuberculosis. These findings establish depletion of intrabacterial magnesium as an antimicrobial mechanism of action and show that M. tuberculosis magnesium homeostasis is vulnerable to disruption by structurally diverse, nonchelating, drug-like compounds.
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Towards A Molecular Understanding of The Cannabinoid Related Orphan Receptor GPR18: A Focus on Its Constitutive Activity. Int J Mol Sci 2019; 20:ijms20092300. [PMID: 31075933 PMCID: PMC6539512 DOI: 10.3390/ijms20092300] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 05/07/2019] [Accepted: 05/08/2019] [Indexed: 12/14/2022] Open
Abstract
The orphan G-protein coupled receptor (GPCR), GPR18, has been recently proposed as a potential member of the cannabinoid family as it recognizes several endogenous, phytogenic, and synthetic cannabinoids. Potential therapeutic applications for GPR18 include intraocular pressure, metabolic disorders, and cancer. GPR18 has been reported to have high constitutive activity, i.e., activation/signaling occurs in the absence of an agonist. This activity can be reduced significantly by the A3.39N mutation. At the intracellular (IC) ends of (transmembrane helices) TMH3 and TMH6 in GPCRs, typically, a pair of oppositely charged amino acids form a salt bridge called the "ionic lock". Breaking of this salt bridge creates an IC opening for coupling with G protein. The GPR18 "ionic lock" residues (R3.50/S6.33) can form only a hydrogen bond. In this paper, we test the hypothesis that the high constitutive activity of GPR18 is due to the weakness of its "ionic lock" and that the A3.39N mutation strengthens this lock. To this end, we report molecular dynamics simulations of wild-type (WT) GPR18 and the A3.39N mutant in fully hydrated (POPC) phophatidylcholine lipid bilayers. Results suggest that in the A3.39N mutant, TMH6 rotates and brings R3.50 and S6.33 closer together, thus strengthening the GPR18 "ionic lock".
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Butler A, Zhang Y, Stuart AG, Dempsey CE, Hancox JC. Functional and pharmacological characterization of an S5 domain hERG mutation associated with short QT syndrome. Heliyon 2019; 5:e01429. [PMID: 31049424 PMCID: PMC6479114 DOI: 10.1016/j.heliyon.2019.e01429] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 02/21/2019] [Accepted: 03/22/2019] [Indexed: 11/18/2022] Open
Abstract
Congenital short QT syndrome (SQTS) is a repolarization disorder characterized by abbreviated QT intervals, atrial and ventricular arrhythmias and a risk of sudden death. This study characterized a missense mutation (I560T) in the S5 domain of the hERG K+ channel that has been associated with variant 1 of the SQTS. Whole cell patch clamp recordings of wild-type (WT) and I560T hERG current (IhERG) were made at 37 °C from hERG expressing HEK 293 cells, and the structural context of the mutation was investigated using a recently reported cryo-EM structure of hERG. Under conventional voltage clamp, the I560T mutation increased IhERG amplitude without altering the voltage-dependence of activation, although it accelerated activation time-course and also slowed deactivation time-course at some voltages. The voltage dependence of IhERG inactivation was positively shifted (by ∼24 mV) and the time-course of inactivation was slowed by the I560T mutation. There was also a modest decrease in K+ over Na+ ion selectivity with the I560T mutation. Under action potential (AP) voltage clamp, the net charge carried by hERG was significantly increased during ventricular, Purkinje fibre and atrial APs, with maximal IhERG also occurring earlier during the plateau phase of ventricular and Purkinje fibre APs. The I560T mutation exerted only a modest effect on quinidine sensitivity of IhERG: the IC50 for mutant IhERG was 2.3 fold that for WT IhERG under conventional voltage clamp. Under AP voltage clamp the inhibitory effect of 1 μM quinidine was largely retained for I560T hERG and the timing of peak I560T IhERG was altered towards that of the WT channel. In both the open channel structure and a closed hERG channel model based on the closely-related EAG structure, I560T side-chains were oriented towards membrane lipid and away from adjacent domains of the channel, contrasting with previous predictions based on homology modelling. In summary, the I560T mutation produces multiple effects on hERG channel operation that result in a gain-of-function that is expected to abbreviate ventricular, atrial and Purkinje fibre repolarization. Quinidine is likely to be of value in offsetting the increase in IhERG and altered IhERG timing during ventricular APs in SQTS with this mutation.
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Affiliation(s)
- Andrew Butler
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, BS8 1TD, United Kingdom
| | - Yihong Zhang
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, BS8 1TD, United Kingdom
- Corresponding author.
| | - A. Graham Stuart
- Bristol Heart Institute, University of Bristol, Bristol, BS2 8HW, United Kingdom
| | - Christopher E. Dempsey
- School of Biochemistry, Medical Sciences Building, University Walk, Bristol, BS8 1TD, United Kingdom
| | - Jules C. Hancox
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, BS8 1TD, United Kingdom
- Bristol Heart Institute, University of Bristol, Bristol, BS2 8HW, United Kingdom
- Corresponding author.
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Llinas Del Torrent C, Casajuana-Martin N, Pardo L, Tresadern G, Pérez-Benito L. Mechanisms Underlying Allosteric Molecular Switches of Metabotropic Glutamate Receptor 5. J Chem Inf Model 2019; 59:2456-2466. [PMID: 30811196 DOI: 10.1021/acs.jcim.8b00924] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The metabotropic glutamate 5 (mGlu5) receptor is a class C G protein-coupled receptor (GPCR) that is implicated in several CNS disorders making it a popular drug discovery target. Years of research have revealed allosteric mGlu5 ligands showing an unexpected complete switch in functional activity despite only small changes in their chemical structure, resulting in positive allosteric modulators (PAM) or negative allosteric modulators (NAM) for the same scaffold. Up to now, the origins of this effect are not understood, causing difficulties in a drug discovery context. In this work, experimental data was gathered and analyzed alongside docking and Molecular Dynamics (MD) calculations for three sets of PAM and NAM pairs. The results consistently show the role of specific interactions formed between ligand substituents and amino acid side chains that block or promote local movements associated with receptor activation. The work provides an explanation for how such small structural changes lead to remarkable differences in functional activity. While this work can greatly help drug discovery programs avoid these switches, it also provides valuable insight into the mechanisms of class C GPCR allosteric activation. Furthermore, the approach shows the value of applying MD to understand functional activity in drug design programs, even for such close structural analogues.
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Affiliation(s)
- Claudia Llinas Del Torrent
- Laboratori de Medicina Computacional Unitat de Bioestadistica, Facultat de Medicina , Universitat Autonoma de Barcelona , 08193 Bellaterra , Spain
| | - Nil Casajuana-Martin
- Laboratori de Medicina Computacional Unitat de Bioestadistica, Facultat de Medicina , Universitat Autonoma de Barcelona , 08193 Bellaterra , Spain
| | - Leonardo Pardo
- Laboratori de Medicina Computacional Unitat de Bioestadistica, Facultat de Medicina , Universitat Autonoma de Barcelona , 08193 Bellaterra , Spain
| | - Gary Tresadern
- Computational Chemistry, Janssen Research & Development , Janssen Pharmaceutica N. V. , Turnhoutseweg 30 , B-2340 Beerse , Belgium
| | - Laura Pérez-Benito
- Laboratori de Medicina Computacional Unitat de Bioestadistica, Facultat de Medicina , Universitat Autonoma de Barcelona , 08193 Bellaterra , Spain.,Computational Chemistry, Janssen Research & Development , Janssen Pharmaceutica N. V. , Turnhoutseweg 30 , B-2340 Beerse , Belgium
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24
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Design and structural characterisation of monomeric water-soluble α-helix and β-hairpin peptides: State-of-the-art. Arch Biochem Biophys 2019; 661:149-167. [DOI: 10.1016/j.abb.2018.11.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 11/06/2018] [Accepted: 11/14/2018] [Indexed: 02/06/2023]
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25
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Abstract
Hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels show an inverted voltage response compared with virtually all other voltage-gated channels, opening on hyperpolarization rather than depolarization. Although the structure of the HCN1 channel was recently solved, the structural element(s) responsible for the inverted gating polarity of HCN is not known. Here, we use a hierarchical approach, by first characterizing the functional contribution of each structural element to channel gating, and then identifying the critical interactions between these elements. Our studies reveal that the HCN voltage sensor can gate the same pore open on both depolarization and hyperpolarization, thereby acting as a bipolar switch. Elements in the pore domain shut off the depolarization-activation pathway in wild-type channels. Despite sharing a common architecture with archetypal voltage-gated ion channels (VGICs), hyperpolarization- and cAMP-activated ion (HCN) channels open upon hyperpolarization rather than depolarization. The basic motions of the voltage sensor and pore gates are conserved, implying that these domains are inversely coupled in HCN channels. Using structure-guided protein engineering, we systematically assembled an array of mosaic channels that display the full complement of voltage-activation phenotypes observed in the VGIC superfamily. Our studies reveal that the voltage sensor of the HCN channel has an intrinsic ability to drive pore opening in either direction and that the extra length of the HCN S4 is not the primary determinant for hyperpolarization activation. Tight interactions at the HCN voltage sensor–pore interface drive the channel into an hERG-like inactivated state, thereby obscuring its opening upon depolarization. This structural element in synergy with the HCN cyclic nucleotide-binding domain and specific interactions near the pore gate biases the channel toward hyperpolarization-dependent opening. Our findings reveal an unexpected common principle underpinning voltage gating in the VGIC superfamily and identify the essential determinants of gating polarity.
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26
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Karanji AK, Khakinejad M, Kondalaji SG, Majuta SN, Attanayake K, Valentine SJ. Comparison of Peptide Ion Conformers Arising from Non-Helical and Helical Peptides Using Ion Mobility Spectrometry and Gas-Phase Hydrogen/Deuterium Exchange. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:2402-2412. [PMID: 30324261 PMCID: PMC6553874 DOI: 10.1007/s13361-018-2053-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 07/17/2018] [Accepted: 08/03/2018] [Indexed: 05/06/2023]
Abstract
The dominant gas-phase conformer of [M+3H]3+ ions of the model peptide acetyl-PSSSSKSSSSKSSSSKSSSSK has been examined with ion mobility spectrometry (IMS), gas-phase hydrogen deuterium exchange (HDX), and mass spectrometry (MS) techniques. The [M+3H]3+ peptide ions are observed predominantly as a relatively compact conformer type. Upon subjecting these ions to electron transfer dissociation (ETD), the level of protection for each amino acid residue in the peptide sequence is assessed. The overall per-residue deuterium uptake is observed to be relatively more efficient for the neutral residues than for the model peptide acetyl-PAAAAKAAAAKAAAAKAAAAK. In comparison, the N-terminal and C-terminal regions of the serine peptide show greater relative protection compared with interior residues. Molecular dynamics (MD) simulations have been used to generate candidate structures for collision cross section and HDX reactivity matching. Hydrogen accessibility scoring (HAS) for select structural candidates from MD simulations has been used to suggest conformer types that could contribute to the observed HDX patterns. The results are discussed with respect to recent studies employing extensive MD simulations of gas-phase structure establishment of a peptide system. Graphical Abstract ᅟ.
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Affiliation(s)
- Ahmad Kiani Karanji
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Mahdiar Khakinejad
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, 21218, USA
| | | | - Sandra N Majuta
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Kushani Attanayake
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Stephen J Valentine
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA.
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27
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Sadler JBA, Wenzel DM, Strohacker LK, Guindo-Martínez M, Alam SL, Mercader JM, Torrents D, Ullman KS, Sundquist WI, Martin-Serrano J. A cancer-associated polymorphism in ESCRT-III disrupts the abscission checkpoint and promotes genome instability. Proc Natl Acad Sci U S A 2018; 115:E8900-E8908. [PMID: 30181294 PMCID: PMC6156662 DOI: 10.1073/pnas.1805504115] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Cytokinetic abscission facilitates the irreversible separation of daughter cells. This process requires the endosomal-sorting complexes required for transport (ESCRT) machinery and is tightly regulated by charged multivesicular body protein 4C (CHMP4C), an ESCRT-III subunit that engages the abscission checkpoint (NoCut) in response to mitotic problems such as persisting chromatin bridges within the midbody. Importantly, a human polymorphism in CHMP4C (rs35094336, CHMP4CT232) increases cancer susceptibility. Here, we explain the structural and functional basis for this cancer association: The CHMP4CT232 allele unwinds the C-terminal helix of CHMP4C, impairs binding to the early-acting ESCRT factor ALIX, and disrupts the abscission checkpoint. Cells expressing CHMP4CT232 exhibit increased levels of DNA damage and are sensitized to several conditions that increase chromosome missegregation, including DNA replication stress, inhibition of the mitotic checkpoint, and loss of p53. Our data demonstrate the biological importance of the abscission checkpoint and suggest that dysregulation of abscission by CHMP4CT232 may synergize with oncogene-induced mitotic stress to promote genomic instability and tumorigenesis.
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Affiliation(s)
- Jessica B A Sadler
- Department of Infectious Diseases, Faculty of Life Sciences and Medicine, King's College London, SE1 9RT London, United Kingdom
| | - Dawn M Wenzel
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112
| | - Lauren K Strohacker
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112
| | - Marta Guindo-Martínez
- Joint Barcelona Supercomputing Center-Centre for Genomic Regulation-Institute for Research in Biomedicine Research Program in Computational Biology, Barcelona Supercomputing Center, 08034 Barcelona, Spain
| | - Steven L Alam
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112
| | - Josep M Mercader
- Joint Barcelona Supercomputing Center-Centre for Genomic Regulation-Institute for Research in Biomedicine Research Program in Computational Biology, Barcelona Supercomputing Center, 08034 Barcelona, Spain
- Program in Metabolism, Broad Institute of Harvard and MIT, Cambridge, MA 02142
- Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA 02142
- Diabetes Unit, Massachusetts General Hospital, Boston, MA 02114
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114
| | - David Torrents
- Joint Barcelona Supercomputing Center-Centre for Genomic Regulation-Institute for Research in Biomedicine Research Program in Computational Biology, Barcelona Supercomputing Center, 08034 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
| | - Katharine S Ullman
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112
| | - Wesley I Sundquist
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112;
| | - Juan Martin-Serrano
- Department of Infectious Diseases, Faculty of Life Sciences and Medicine, King's College London, SE1 9RT London, United Kingdom;
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28
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Hu X, Guo J, Yin Z, Shan Z. First Experimental Evidence of Intramolecular Weak Bifurcated H Bond between Aliphatic C-H and Aromatic Cl Atoms: X-Ray Crystallographic Investigation on the syn
Head-to-Head Dimer of 2,6-Dichlorochalcone. ChemistrySelect 2018. [DOI: 10.1002/slct.201702945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Xiaoyun Hu
- College of Chemistry and Materials; South-Central University for Nationalities; Wuhan, Hubei Province China
| | - Jianxin Guo
- College of Chemistry and Materials; South-Central University for Nationalities; Wuhan, Hubei Province China
| | - Zhongyou Yin
- College of Chemistry and Materials; South-Central University for Nationalities; Wuhan, Hubei Province China
| | - Zixing Shan
- College of Chemistry and Molecular Sciences; Wuhan University; Wuhan, Hubei Province China
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29
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Wang J, Li Z, Xu L, Yang H, Liu W. Transmembrane domain dependent inhibitory function of FcγRIIB. Protein Cell 2018; 9:1004-1012. [PMID: 29497990 PMCID: PMC6251803 DOI: 10.1007/s13238-018-0509-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 12/22/2017] [Indexed: 01/26/2023] Open
Abstract
FcγRIIB, the only inhibitory IgG Fc receptor, functions to suppress the hyper-activation of immune cells. Numerous studies have illustrated its inhibitory function through the ITIM motif in the cytoplasmic tail of FcγRIIB. However, later studies revealed that in addition to the ITIM, the transmembrane (TM) domain of FcγRIIB is also indispensable for its inhibitory function. Indeed, recent epidemiological studies revealed that a non-synonymous single nucleotide polymorphism (rs1050501) within the TM domain of FcγRIIB, responsible for the I232T substitution, is associated with the susceptibility to systemic lupus erythematosus (SLE). In this review, we will summarize these epidemiological and functional studies of FcγRIIB-I232T in the past few years, and will further discuss the mechanisms accounting for the functional loss of FcγRIIB-I232T. Our review will help the reader gain a deeper understanding of the importance of the TM domain in mediating the inhibitory function of FcγRIIB and may provide insights to a new therapeutic target for the associated diseases.
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Affiliation(s)
- Junyi Wang
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Zongyu Li
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Liling Xu
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, Harvard University, 400 Technology Square, Cambridge, MA, 02139, USA.
| | - Hengwen Yang
- The First Affiliate Hospital, Biomedical Translational Research Institute, Guangdong Province Key Laboratory of Molecular Immunology and Antibody Engineering, Jinan University, Guangzhou, 510632, China.
| | - Wanli Liu
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
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30
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Tryptophan-mediated Dimerization of the TssL Transmembrane Anchor Is Required for Type VI Secretion System Activity. J Mol Biol 2018; 430:987-1003. [DOI: 10.1016/j.jmb.2018.02.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 01/29/2018] [Accepted: 02/11/2018] [Indexed: 11/23/2022]
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31
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Högel P, Götz A, Kuhne F, Ebert M, Stelzer W, Rand KD, Scharnagl C, Langosch D. Glycine Perturbs Local and Global Conformational Flexibility of a Transmembrane Helix. Biochemistry 2018; 57:1326-1337. [DOI: 10.1021/acs.biochem.7b01197] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Philipp Högel
- Center
for Integrated Protein Science Munich (CIPSM) at the Lehrstuhl Chemie
der Biopolymere, Technical University of Munich, Weihenstephaner
Berg 3, 85354 Freising, Germany
| | - Alexander Götz
- Physics
of Synthetic Biological Systems (E14), Technical University of Munich, Maximus-von-Imhof Forum 4, 85354 Freising, Germany
| | - Felix Kuhne
- Center
for Integrated Protein Science Munich (CIPSM) at the Lehrstuhl Chemie
der Biopolymere, Technical University of Munich, Weihenstephaner
Berg 3, 85354 Freising, Germany
| | - Maximilian Ebert
- Center
for Integrated Protein Science Munich (CIPSM) at the Lehrstuhl Chemie
der Biopolymere, Technical University of Munich, Weihenstephaner
Berg 3, 85354 Freising, Germany
| | - Walter Stelzer
- Center
for Integrated Protein Science Munich (CIPSM) at the Lehrstuhl Chemie
der Biopolymere, Technical University of Munich, Weihenstephaner
Berg 3, 85354 Freising, Germany
| | - Kasper D. Rand
- Department
of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Christina Scharnagl
- Physics
of Synthetic Biological Systems (E14), Technical University of Munich, Maximus-von-Imhof Forum 4, 85354 Freising, Germany
| | - Dieter Langosch
- Center
for Integrated Protein Science Munich (CIPSM) at the Lehrstuhl Chemie
der Biopolymere, Technical University of Munich, Weihenstephaner
Berg 3, 85354 Freising, Germany
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32
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Naing SH, Kalyoncu S, Smalley DM, Kim H, Tao X, George JB, Jonke AP, Oliver RC, Urban VS, Torres MP, Lieberman RL. Both positional and chemical variables control in vitro proteolytic cleavage of a presenilin ortholog. J Biol Chem 2018; 293:4653-4663. [PMID: 29382721 DOI: 10.1074/jbc.ra117.001436] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 01/23/2018] [Indexed: 11/06/2022] Open
Abstract
Mechanistic details of intramembrane aspartyl protease (IAP) chemistry, which is central to many biological and pathogenic processes, remain largely obscure. Here, we investigated the in vitro kinetics of a microbial intramembrane aspartyl protease (mIAP) fortuitously acting on the renin substrate angiotensinogen and the C-terminal transmembrane segment of amyloid precursor protein (C100), which is cleaved by the presenilin subunit of γ-secretase, an Alzheimer disease (AD)-associated IAP. mIAP variants with substitutions in active-site and putative substrate-gating residues generally exhibit impaired, but not abolished, activity toward angiotensinogen and retain the predominant cleavage site (His-Thr). The aromatic ring, but not the hydroxyl substituent, within Tyr of the catalytic Tyr-Asp (YD) motif plays a catalytic role, and the hydrolysis reaction incorporates bulk water as in soluble aspartyl proteases. mIAP hydrolyzes the transmembrane region of C100 at two major presenilin cleavage sites, one corresponding to the AD-associated Aβ42 peptide (Ala-Thr) and the other to the non-pathogenic Aβ48 (Thr-Leu). For the former site, we observed more favorable kinetics in lipid bilayer-mimicking bicelles than in detergent solution, indicating that substrate-lipid and substrate-enzyme interactions both contribute to catalytic rates. High-resolution MS analyses across four substrates support a preference for threonine at the scissile bond. However, results from threonine-scanning mutagenesis of angiotensinogen demonstrate a competing positional preference for cleavage. Our results indicate that IAP cleavage is controlled by both positional and chemical factors, opening up new avenues for selective IAP inhibition for therapeutic interventions.
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Affiliation(s)
- Swe-Htet Naing
- School of Chemistry and Biochemistry, Atlanta, Georgia 30332
| | - Sibel Kalyoncu
- School of Chemistry and Biochemistry, Atlanta, Georgia 30332
| | - David M Smalley
- Petit Institute for Bioengineering and Biosciences, Atlanta, Georgia 30332
| | - Hyojung Kim
- School of Chemistry and Biochemistry, Atlanta, Georgia 30332; School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Xingjian Tao
- School of Chemistry and Biochemistry, Atlanta, Georgia 30332
| | - Josh B George
- School of Chemistry and Biochemistry, Atlanta, Georgia 30332
| | - Alex P Jonke
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Ryan C Oliver
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Volker S Urban
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Matthew P Torres
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332
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33
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Dutta D, Fliegel L. Structure and function of yeast and fungal Na + /H + antiporters. IUBMB Life 2017; 70:23-31. [PMID: 29219228 DOI: 10.1002/iub.1701] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 11/21/2017] [Indexed: 12/22/2022]
Abstract
Sodium proton antiporters (or sodium proton exchangers [NHEs]) are a critical family of membrane proteins that exchange sodium for protons across cell membranes. In yeast and plants, their primary function is to keep the sodium concentration low inside the cytoplasm. One class of NHE constitutively expressed in yeast is the plasma membrane Na+ /H+ antiporter, and another class is expressed on the endosomal/vacuolar membrane. At present, four bacterial plasma membrane antiporter structures are known and nuclear magnetic resonance structures are available for the membrane spanning transmembrane helices of mammalian and yeast NHEs. Additionally, a vast amount of mutational data are available on the role of individual amino acids and critical motifs involved in transport. We combine this information to obtain a more detailed picture of the yeast NHE plasma membrane protein and review mechanisms of transport, conserved motifs, unique residues important in function, and regulation of these proteins. The Na+ /H+ antiporter of Schizosaccharomyces pombe, SpNHE1, is an interesting model protein in an easy to study system and is representative of fungal Na+ /H+ antiporters. © IUBMB Life, 70(1):23-31, 2018.
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Affiliation(s)
- Debajyoti Dutta
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | - Larry Fliegel
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
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34
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Sahoo BR, Fujiwara T. Conformational states of HAMP domains interacting with sensory rhodopsin membrane systems: an integrated all-atom and coarse-grained molecular dynamics simulation approach. MOLECULAR BIOSYSTEMS 2017; 13:193-207. [PMID: 27901172 DOI: 10.1039/c6mb00730a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Understanding the downstream signaling mechanism of sensory rhodopsin and its cognate transducer complex (srII-htrII) has long been a challenge in the field of photoreceptor research. Here, an integration of all-atom and coarse-grained (CG) molecular dynamics (MD) simulations in different srII-htrII complex states is carried out. It is shown that the cytoplasmic four-helix HAMP dimer gives rise to a gear-box model interaction with discrete hydrophobic packing in Natronomonas pharaonis (Np). Structural analysis in all-atom and CG-MD reveals a stable conformational state in the physiological environment (323 K and 1.15 M salt). Comparative analysis in the ground and intermediate state conformations reveals substantial inter-HAMP interactions in the intermediate state with uniform clockwise (+10° to +30°) and counterclockwise (-20° to -40°) rotations in the α1 helix and the α2 helix of the monomer, respectively. Low temperature and low salt environments (283 K and 0.15 M) significantly affect srII-htrII binding affinity in both states with unusual helix bending. The distinguished control cable, knob-into-holes packing and piston-like movements in HAMP helices are found in the intermediate state complex. The N-terminal htrII (159 residues) coupled with srII yields a binding energy (ΔGbind) of -309.22, -436.53 and -331.11 kJ mol-1 in the MM/PBSA calculation for the NphtrII homodimer, the NpsrII-htrII ground state conformation and the NpsrII-htrII intermediate state conformation, respectively. Only the HAMP1 domain shows a very low ΔGbind value (-21.03 kJ mol-1) for the ground state in comparison to that for the intermediate state (-54.68 kJ mol-1). The structural analysis highlights the key residues that include Y199srII, T189srII, E43htrII, T86htrII, M100htrII, E116htrII, E126htrII and S130htrII for complex stabilization and signal transduction.
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Affiliation(s)
- Bikash Ranjan Sahoo
- Laboratory of Molecular Biophysics, Institute for Protein Research, Osaka University, 5650871, Japan.
| | - Toshimichi Fujiwara
- Laboratory of Molecular Biophysics, Institute for Protein Research, Osaka University, 5650871, Japan.
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35
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Abstract
The Reggio group has constructed computer models of the inactive and G-protein-activated states of the cannabinoid CB1 and CB2 receptors, as well as, several orphan receptors that recognize a subset of cannabinoid compounds, including GPR55 and GPR18. These models have been used to design ligands, mutations, and covalent labeling studies. The resultant second-generation models have been used to design ligands with improved affinity, efficacy, and subtype selectivity. Herein, we provide a guide for the development of GPCR models using the most recent orphan receptor studied in our lab, GPR3. GPR3 is an orphan receptor that belongs to the Class A family of G-protein-coupled receptors. It shares high sequence similarity with GPR6, GPR12, the lysophospholipid receptors, and the cannabinoid receptors. GPR3 is predominantly expressed in mammalian brain and oocytes and it is known as a Gαs-coupled receptor activated constitutively in cells. GPR3 represents a possible target for the treatment of different pathological conditions such as Alzheimer's disease, oocyte maturation, or neuropathic pain. However, the lack of potent and selective GPR3 ligands is delaying the exploitation of this promising therapeutic target. In this context, we aim to develop a homology model that helps us to elucidate the structural determinants governing ligand-receptor interactions at GPR3. In this chapter, we detail the methods and rationale behind the construction of the GPR3 active-and inactive-state models. These homology models will enable the rational design of novel ligands, which may serve as research tools for further understanding of the biological role of GPR3.
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Affiliation(s)
- Paula Morales
- University of North Carolina at Greensboro, Greensboro, NC, United States.
| | - Dow P Hurst
- University of North Carolina at Greensboro, Greensboro, NC, United States
| | - Patricia H Reggio
- University of North Carolina at Greensboro, Greensboro, NC, United States
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36
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37
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Irudayanathan FJ, Wang N, Wang X, Nangia S. Architecture of the paracellular channels formed by claudins of the blood–brain barrier tight junctions. Ann N Y Acad Sci 2017; 1405:131-146. [DOI: 10.1111/nyas.13378] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/12/2017] [Accepted: 04/14/2017] [Indexed: 01/31/2023]
Affiliation(s)
| | - Nan Wang
- Department of Biomedical and Chemical Engineering Syracuse University Syracuse New York
| | - Xiaoyi Wang
- Department of Biomedical and Chemical Engineering Syracuse University Syracuse New York
| | - Shikha Nangia
- Department of Biomedical and Chemical Engineering Syracuse University Syracuse New York
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38
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Rauh O, Urban M, Henkes LM, Winterstein T, Greiner T, Van Etten JL, Moroni A, Kast SM, Thiel G, Schroeder I. Identification of Intrahelical Bifurcated H-Bonds as a New Type of Gate in K + Channels. J Am Chem Soc 2017; 139:7494-7503. [PMID: 28499087 PMCID: PMC6638992 DOI: 10.1021/jacs.7b01158] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Gating
of ion channels is based on structural transitions between
open and closed states. To uncover the chemical basis of individual
gates, we performed a comparative experimental and computational analysis
between two K+ channels, KcvS and KcvNTS. These small viral encoded K+ channel proteins, with
a monomer size of only 82 amino acids, resemble the pore module of
all complex K+ channels in terms of structure and function.
Even though both proteins share about 90% amino acid sequence identity,
they exhibit different open probabilities with ca. 90% in KcvNTS and 40% in KcvS. Single channel analysis, mutational
studies and molecular dynamics simulations show that the difference
in open probability is caused by one long closed state in KcvS. This state is structurally created in the tetrameric channel
by a transient, Ser mediated, intrahelical hydrogen bond. The resulting
kink in the inner transmembrane domain swings the aromatic rings from
downstream Phes in the cavity of the channel, which blocks ion flux.
The frequent occurrence of Ser or Thr based helical kinks in membrane
proteins suggests that a similar mechanism could also occur in the
gating of other ion channels.
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Affiliation(s)
- Oliver Rauh
- Plant Membrane Biophysics, Technical University Darmstadt , 64289 Darmstadt, Germany
| | - Martin Urban
- Physikalische Chemie III, Technische Universität Dortmund , 44227 Dortmund, Germany
| | - Leonhard M Henkes
- Physikalische Chemie III, Technische Universität Dortmund , 44227 Dortmund, Germany
| | - Tobias Winterstein
- Plant Membrane Biophysics, Technical University Darmstadt , 64289 Darmstadt, Germany
| | - Timo Greiner
- Plant Membrane Biophysics, Technical University Darmstadt , 64289 Darmstadt, Germany
| | - James L Van Etten
- Department of Plant Pathology and Nebraska Center for Virology, University of Nebraska Lincoln , Lincoln, Nebraska 68583-0900, United States
| | - Anna Moroni
- Department of Biosciences and CNR IBF-Mi, Università degli Studi di Milano , 20122 Milano, Italy
| | - Stefan M Kast
- Physikalische Chemie III, Technische Universität Dortmund , 44227 Dortmund, Germany
| | - Gerhard Thiel
- Plant Membrane Biophysics, Technical University Darmstadt , 64289 Darmstadt, Germany
| | - Indra Schroeder
- Plant Membrane Biophysics, Technical University Darmstadt , 64289 Darmstadt, Germany
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39
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Richards R, Dempski RE. Adjacent channelrhodopsin-2 residues within transmembranes 2 and 7 regulate cation selectivity and distribution of the two open states. J Biol Chem 2017; 292:7314-7326. [PMID: 28302720 DOI: 10.1074/jbc.m116.770321] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 03/14/2017] [Indexed: 11/06/2022] Open
Abstract
Channelrhodopsin-2 (ChR2) is a light-activated channel that can conduct cations of multiple valencies down the electrochemical gradient. Under continuous light exposure, ChR2 transitions from a high-conducting open state (O1) to a low-conducting open state (O2) with differing ion selectivity. The molecular basis for the O1 → O2 transition and how ChR2 modulates selectivity between states is currently unresolved. To this end, we used steered molecular dynamics, electrophysiology, and kinetic modeling to identify residues that contribute to gating and selectivity in discrete open states. Analysis of steered molecular dynamics experiments identified three transmembrane residues (Val-86, Lys-93, and Asn-258) that form a putative barrier to ion translocation. Kinetic modeling of photocurrents generated from ChR2 proteins with conservative mutations at these positions demonstrated that these residues contribute to cation selectivity (Val-86 and Asn-258), the transition between the two open states (Val-86), open channel stability, and the hydrogen-bonding network (K93I and K93N). These results suggest that this approach can be used to identify residues that contribute to the open-state transitions and the discrete ion selectivity within these states. With the rise of ChR2 use in optogenetics, it will be critical to identify residues that contribute to O1 or O2 selectivity and gating to minimize undesirable effects.
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Affiliation(s)
- Ryan Richards
- From the Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts 01609
| | - Robert E Dempski
- From the Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts 01609
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40
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Intramolecular single H bonding vs bifurcation in tuning the conformation of 2,2′-dihydroxybenzophenone and its derivatives: a DFT insight. Struct Chem 2016. [DOI: 10.1007/s11224-016-0895-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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41
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Xu L, Xia M, Guo J, Sun X, Li H, Xu C, Gu X, Zhang H, Yi J, Fang Y, Xie H, Wang J, Shen Z, Xue B, Sun Y, Meckel T, Chen YH, Hu Z, Li Z, Xu C, Gong H, Liu W. Impairment on the lateral mobility induced by structural changes underlies the functional deficiency of the lupus-associated polymorphism FcγRIIB-T232. J Exp Med 2016; 213:2707-2727. [PMID: 27799621 PMCID: PMC5110019 DOI: 10.1084/jem.20160528] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 08/08/2016] [Accepted: 09/28/2016] [Indexed: 12/18/2022] Open
Abstract
Xu et al. show that the lupus-associated polymorphism FcγRIIB-T232 has structural changes of the TM domain that reduces lateral mobility and inhibitory functions. FcγRIIB functions to suppress the activation of immune cells. A single-nucleotide polymorphism in the transmembrane (TM) domain of FcγRIIB, FcγRIIB-T232, is associated with lupus. In this study, we investigated the pathogenic mechanism of FcγRIIB-T232 at both functional and structural levels. Our results showed that FcγRIIB-T232 exhibited significantly reduced lateral mobility compared with FcγRIIB-I232 and was significantly less enriched into the microclusters of immune complexes (ICs) after stimulation. However, if sufficient responding time is given for FcγRIIB-T232 to diffuse and interact with the ICs, FcγRIIB-T232 can restore its inhibitory function. Moreover, substituting the FcγRIIB-T232 TM domain with that of a fast floating CD86 molecule restored both the rapid mobility and the inhibitory function, which further corroborated the importance of fast mobility for FcγRIIB to function. Mechanistically, the crippled lateral mobility of FcγRIIB-T232 can be explained by the structural changes of the TM domain. Both atomistic simulations and nuclear magnetic resonance measurement indicated that the TM helix of FcγRIIB-T232 exhibited a more inclined orientation than that of FcγRIIB-I232, thus resulting in a longer region embedded in the membrane. Therefore, we conclude that the single-residue polymorphism T232 enforces the inclination of the TM domain and thereby reduces the lateral mobility and inhibitory functions of FcγRIIB.
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Affiliation(s)
- Liling Xu
- Ministry of Education Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Mengdie Xia
- Ministry of Education Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jun Guo
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiaolin Sun
- Department of Rheumatology and Immunology, Clinical Immunology Center, Peking University People's Hospital, Beijing 100044, China
| | - Hua Li
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Chenguang Xu
- Ministry of Education Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaomei Gu
- Ministry of Education Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Haowen Zhang
- Ministry of Education Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Junyang Yi
- Ministry of Education Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yan Fang
- Ministry of Education Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hengyi Xie
- Ministry of Education Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jing Wang
- Ministry of Education Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Zhixun Shen
- Ministry of Education Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Boxin Xue
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Biodynamic Optical Imaging Center, School of Life Sciences, Peking University, Beijing 100871, China
| | - Yujie Sun
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Biodynamic Optical Imaging Center, School of Life Sciences, Peking University, Beijing 100871, China
| | - Tobias Meckel
- Membrane Dynamics, Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Ying-Hua Chen
- Ministry of Education Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Zhibin Hu
- Department of Epidemiology, School of Public Health, Nanjing Medical University, Nanjing 211166, China
| | - Zhanguo Li
- Department of Rheumatology and Immunology, Clinical Immunology Center, Peking University People's Hospital, Beijing 100044, China
| | - Chenqi Xu
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China .,School of Life Science and Technology, ShanghaiTech University, Shanghai 200031, China
| | - Haipeng Gong
- Ministry of Education Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wanli Liu
- Ministry of Education Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Immunology, School of Life Sciences, Tsinghua University, Beijing 100084, China
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42
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Tavella D, Deveau LM, Whitfield TW, Massi F. Structural Basis of the Disorder in the Tandem Zinc Finger Domain of the RNA-Binding Protein Tristetraprolin. J Chem Theory Comput 2016; 12:4717-4725. [PMID: 27487322 DOI: 10.1021/acs.jctc.6b00150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Tristetraprolin (TTP) and TIS11d are two human RNA-binding proteins that belong to the CCCH-type tandem zinc finger family. In the RNA-free state, TIS11d coordinates a zinc ion in each of its two fingers, while TTP coordinates a single zinc ion with the N-terminal zinc finger. We have previously identified three residues, located in the C-terminal half of a short α-helix in the second zinc finger, that control how structured the RNA-binding domain is in these two proteins: Y151, L152, and Q153 in TTP and H201, T202, and I203 in TIS11d. Here, we have used molecular dynamics, NMR spectroscopy, and other biochemical methods to investigate the role of these three residues in the stability of the RNA-binding domain. We found that the intrahelical hydrogen bond formed by the T202 hydroxyl group in the C-terminal zinc finger of TIS11d is necessary to allow for π-π stacking between the side chains of a conserved phenylalanine and the zinc-coordinating histidine. We demonstrated that the lack of this hydrogen bond in TTP is responsible for the reduced zinc affinity of the C-terminal zinc finger.
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Affiliation(s)
- Davide Tavella
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School , Worcester, Massachusetts 01605, United States
| | - Laura M Deveau
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School , Worcester, Massachusetts 01605, United States
| | - Troy W Whitfield
- Department of Medicine, University of Massachusetts Medical School , Worcester, Massachusetts 01605, United States.,Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School , Worcester, Massachusetts 01605, United States
| | - Francesca Massi
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School , Worcester, Massachusetts 01605, United States
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43
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Boiteux C, Allen TW. Understanding Sodium Channel Function and Modulation Using Atomistic Simulations of Bacterial Channel Structures. CURRENT TOPICS IN MEMBRANES 2016; 78:145-82. [PMID: 27586284 DOI: 10.1016/bs.ctm.2016.07.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Sodium channels are chief proteins involved in electrical signaling in the nervous system, enabling critical functions like heartbeat and brain activity. New high-resolution X-ray structures for bacterial sodium channels have created an opportunity to see how these proteins operate at the molecular level. An important challenge to overcome is establishing relationships between the structures and functions of mammalian and bacterial channels. Bacterial sodium channels are known to exhibit the main structural features of their mammalian counterparts, as well as several key functional characteristics, including selective ion conduction, voltage-dependent gating, pore-based inactivation and modulation by local anesthetic, antiarrhythmic and antiepileptic drugs. Simulations have begun to shed light on each of these features in the past few years. Despite deviations in selectivity signatures for bacterial and mammalian channels, simulations have uncovered the nature of the multiion conduction mechanism associated with Na(+) binding to a high-field strength site established by charged glutamate side chains. Simulations demonstrated a surprising level of flexibility of the protein, showing that these side chains are active participants in the permeation process. They have also uncovered changes in protein structure, leading to asymmetrical collapses of the activation gate that have been proposed to correspond to inactivated structures. These observations offer the potential to examine the mechanisms of state-dependent drug activity, focusing on pore-blocking and pore-based slow inactivation in bacterial channels, without the complexities of inactivation on multiple timescales seen in eukaryotic channels. Simulations have provided molecular views of the interactions of drugs, consistent with sites predicted in mammalian channels, as well as a wealth of other sites as potential new drug targets. In this chapter, we survey the new insights into sodium channel function that have emerged from studies of simpler bacterial channels, which provide an excellent learning platform, and promising avenues for mechanistic discovery and pharmacological development.
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Affiliation(s)
- C Boiteux
- RMIT University, Melbourne, VIC, Australia
| | - T W Allen
- RMIT University, Melbourne, VIC, Australia; University of California Davis, Davis, CA, United States
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44
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Ung PMU, Song W, Cheng L, Zhao X, Hu H, Chen L, Schlessinger A. Inhibitor Discovery for the Human GLUT1 from Homology Modeling and Virtual Screening. ACS Chem Biol 2016; 11:1908-16. [PMID: 27128978 DOI: 10.1021/acschembio.6b00304] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The human Glucose Transporter 1 (hGLUT1 or SLC2A1) is a facilitative membrane transporter found in the liver, intestines, kidney, and brain, where it transports sugars such as d-glucose and d-galactose. Genetic variations in hGLUT1 are associated with a broad range of diseases and metabolic disorders. For example, hGLUT1 is upregulated in various cancer types (e.g., breast carcinoma) to support the increased anaerobic glycolysis and the Warburg effect. Thus, hGLUT1 is an emerging therapeutic target, which also transports commonly used cancer biomarkers (e.g., (18)F-DG). In this study, we use computational prediction followed by experimental testing, to characterize hGLUT1. We construct homology models of hGLUT1 in a partially occluded outward open ("occluded") conformation based on the X-ray structure of the E. coli xylose transporter, XylE. Comparison of the binding site of the occluded models to experimentally determined hGLUT structures revealed a hydrophobic pocket adjacent to the sugar-binding site, which was tested experimentally via site-directed mutagenesis. Virtual screening of various libraries of purchasable compounds against the occluded models, followed by experimental testing with cellular assays revealed seven previously unknown hGLUT1 ligands with IC50 values ranging from 0.45 μM to 59 μM. These ligands represent three unique chemotypes that are chemically different from any other known hGLUT1 ligands. The newly characterized hydrophobic pocket can potentially be utilized by the new ligands for increased affinity. Furthermore, the previously unknown hGLUT1 ligands can serve as chemical tools to further characterize hGLUT1 function or lead molecules for future drug development.
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Affiliation(s)
- Peter Man-Un Ung
- Department
of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Wenxin Song
- School
of Pharmaceutical Sciences, Tsinghua University, Beijing, China 100084
| | - Lili Cheng
- School
of Pharmaceutical Sciences, Tsinghua University, Beijing, China 100084
| | - Xinbin Zhao
- School
of Pharmaceutical Sciences, Tsinghua University, Beijing, China 100084
| | - Hailin Hu
- School
of Pharmaceutical Sciences, Tsinghua University, Beijing, China 100084
| | - Ligong Chen
- School
of Pharmaceutical Sciences, Tsinghua University, Beijing, China 100084
| | - Avner Schlessinger
- Department
of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
- Department
of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
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45
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Wani NA, Gupta VK, Singh UP, Aravinda S, Rai R. Folded Structure Stabilized by C 7, C 10and C 12Hydrogen Bonds in αγ Hybrid Peptides. ChemistrySelect 2016. [DOI: 10.1002/slct.201600389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Naiem Ahmad Wani
- Medicinal Chemistry Division; Indian Institute of Integrative Medicine; Canal Road, Jammu- 180001 India
| | - Vivek Kumar Gupta
- X-ray Crystallography Laboratory; Post-Graduate Department of Physics and Electronics; University of Jammu; Jammu Tawi 180 006 India
| | - Umesh Prasad Singh
- CSIR-Indian Institute of Chemical Biology; 4, Raja, S.C. Mullick Road Kolkata- 700032 India
| | - Subrayashastry Aravinda
- Medicinal Chemistry Division; Indian Institute of Integrative Medicine; Canal Road, Jammu- 180001 India
| | - Rajkishor Rai
- Medicinal Chemistry Division; Indian Institute of Integrative Medicine; Canal Road, Jammu- 180001 India
- Academy of Scientific and Innovative Research; New Delhi India
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46
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Shi H, Zhang T, Yi Y, Wang H, Luo J. Long form PRLR (lPRLR) regulates genes involved in the triacylglycerol synthesis in goat mammary gland epithelial cells. Small Rumin Res 2016. [DOI: 10.1016/j.smallrumres.2016.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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47
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Kyriakou PK, Ekblad B, Kristiansen PE, Kaznessis YN. Interactions of a class IIb bacteriocin with a model lipid bilayer, investigated through molecular dynamics simulations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:824-35. [PMID: 26774214 DOI: 10.1016/j.bbamem.2016.01.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 01/06/2016] [Accepted: 01/12/2016] [Indexed: 01/15/2023]
Abstract
The emergence of antibiotic resistant microorganisms poses an alarming threat to global health. Antimicrobial peptides (AMPs) are considered a possible effective alternative to conventional antibiotic therapies. An understanding of the mechanism of action of AMPs is needed in order to better control and optimize their bactericidal activity. Plantaricin EF is a heterodimeric AMP, consisting of two peptides Plantaricin E (PlnE) and Plantaricin F (PlnF). We studied the behavior of these peptides on the surface of a model lipid bilayer. We identified the residues that facilitate peptide-peptide interactions. We also identified residues that mediate interactions of the dimer with the membrane. PlnE interacts with the membrane through amino acids at both its termini, while only the N terminus of PlnF approaches the membrane. By comparing the activity of single-site mutants of the two-peptide bacteriocin and the simulations of the bacteriocin on the surface of a model lipid bilayer, structure activity relationships are proposed. These studies allow us to generate hypotheses that relate biophysical interactions observed in simulations with the experimentally measured activity. We find that single-site amino acid substitutions result in markedly stronger antimicrobial activity when they strengthen the interactions between the two peptides, while, concomitantly, they weaken peptide-membrane association. This effect is more pronounced in the case of the PlnE mutant (G20A), which interacts the strongest with PlnF and the weakest with the membrane while displaying the highest activity.
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Affiliation(s)
- Panagiota K Kyriakou
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, United States
| | - Bie Ekblad
- Department of Biosciences, University of Oslo, Post box 1041 Blindern, 0316 Oslo, Norway
| | - Per Eugen Kristiansen
- Department of Biosciences, University of Oslo, Post box 1041 Blindern, 0316 Oslo, Norway
| | - Yiannis N Kaznessis
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, United States.
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48
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Thomas J, Liu X, Jäger W, Xu Y. Unusual H-Bond Topology and Bifurcated H-bonds in the 2-Fluoroethanol Trimer. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201505934] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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49
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Thomas J, Liu X, Jäger W, Xu Y. Unusual H-Bond Topology and Bifurcated H-bonds in the 2-Fluoroethanol Trimer. Angew Chem Int Ed Engl 2015; 54:11711-5. [PMID: 26276699 DOI: 10.1002/anie.201505934] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Indexed: 11/06/2022]
Abstract
By using a combination of rotational spectroscopy and ab initio calculations, an unusual H-bond topology was revealed for the 2-fluoroethanol trimer. The trimer exhibits a strong heterochiral preference and adopts an open OH⋅⋅⋅OH H-bond topology while utilizing two types of bifurcated H-bonds involving organic fluorine. This is in stark contrast to the cyclic OH⋅⋅⋅OH H-bond topology adopted by trimers of water and other simple alcohols. The strengths of different H-bonds in the trimer were analyzed by using the quantum theory of atoms in molecules. The study showcases a remarkable example of a chirality-induced switch in H-bond topology in a simple transient chiral fluoroalcohol. It provides important insight into the H-bond topologies of small fluoroalcohol aggregates, which are proposed to play a key role in protein folding and in enantioselective reactions and separations where fluoroalcohols serve as a (co)solvent.
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Affiliation(s)
- Javix Thomas
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2 (Canada)
| | - Xunchen Liu
- School of Mechanical Engineering, Shanghai Jiao Tong University, No.800 Dong Chuan Road, Shanghai, 200240 (P.R. China)
| | - Wolfgang Jäger
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2 (Canada)
| | - Yunjie Xu
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2 (Canada).
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50
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Nash A, Notman R, Dixon AM. De novo design of transmembrane helix–helix interactions and measurement of stability in a biological membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1248-57. [DOI: 10.1016/j.bbamem.2015.02.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 01/29/2015] [Accepted: 02/18/2015] [Indexed: 01/03/2023]
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