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Aleksandrova AA, Sarti E, Forrest LR. EncoMPASS: An encyclopedia of membrane proteins analyzed by structure and symmetry. Structure 2024; 32:492-504.e4. [PMID: 38367624 DOI: 10.1016/j.str.2024.01.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 01/09/2024] [Accepted: 01/10/2024] [Indexed: 02/19/2024]
Abstract
Protein structure determination and prediction, active site detection, and protein sequence alignment techniques all exploit information about protein structure and structural relationships. For membrane proteins, however, there is limited agreement among available online tools for highlighting and mapping such structural similarities. Moreover, no available resource provides a systematic overview of quaternary and internal symmetries, and their orientation relative to the membrane, despite the fact that these properties can provide key insights into membrane protein function and evolution. Here, we describe the Encyclopedia of Membrane Proteins Analyzed by Structure and Symmetry (EncoMPASS), a database for relating integral membrane proteins of known structure from the points of view of sequence, structure, and symmetry. EncoMPASS is accessible through a web interface, and its contents can be easily downloaded. This allows the user not only to focus on specific proteins, but also to study general properties of the structure and evolution of membrane proteins.
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Affiliation(s)
- Antoniya A Aleksandrova
- Computational Structural Biology Section, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Edoardo Sarti
- Computational Structural Biology Section, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lucy R Forrest
- Computational Structural Biology Section, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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Meluzzi D, Arya G. Computational approaches for inferring 3D conformations of chromatin from chromosome conformation capture data. Methods 2020; 181-182:24-34. [PMID: 31470090 PMCID: PMC7044057 DOI: 10.1016/j.ymeth.2019.08.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/24/2019] [Accepted: 08/23/2019] [Indexed: 02/08/2023] Open
Abstract
Chromosome conformation capture (3C) and its variants are powerful experimental techniques for probing intra- and inter-chromosomal interactions within cell nuclei at high resolution and in a high-throughput, quantitative manner. The contact maps derived from such experiments provide an avenue for inferring the 3D spatial organization of the genome. This review provides an overview of the various computational methods developed in the past decade for addressing the very important but challenging problem of deducing the detailed 3D structure or structure population of chromosomal domains, chromosomes, and even entire genomes from 3C contact maps.
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Affiliation(s)
- Dario Meluzzi
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, United States
| | - Gaurav Arya
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, United States.
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Huffer KE, Aleksandrova AA, Jara-Oseguera A, Forrest LR, Swartz KJ. Global alignment and assessment of TRP channel transmembrane domain structures to explore functional mechanisms. eLife 2020; 9:e58660. [PMID: 32804077 PMCID: PMC7431192 DOI: 10.7554/elife.58660] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 07/31/2020] [Indexed: 12/20/2022] Open
Abstract
The recent proliferation of published TRP channel structures provides a foundation for understanding the diverse functional properties of this important family of ion channel proteins. To facilitate mechanistic investigations, we constructed a structure-based alignment of the transmembrane domains of 120 TRP channel structures. Comparison of structures determined in the absence or presence of activating stimuli reveals similar constrictions in the central ion permeation pathway near the intracellular end of the S6 helices, pointing to a conserved cytoplasmic gate and suggesting that most available structures represent non-conducting states. Comparison of the ion selectivity filters toward the extracellular end of the pore supports existing hypotheses for mechanisms of ion selectivity. Also conserved to varying extents are hot spots for interactions with hydrophobic ligands, lipids and ions, as well as discrete alterations in helix conformations. This analysis therefore provides a framework for investigating the structural basis of TRP channel gating mechanisms and pharmacology, and, despite the large number of structures included, reveals the need for additional structural data and for more functional studies to establish the mechanistic basis of TRP channel function.
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Affiliation(s)
- Katherine E Huffer
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Diseases and Stroke, National Institutes of HealthBethesdaUnited States
| | - Antoniya A Aleksandrova
- Computational Structural Biology Section, Porter Neuroscience Research Center, National Institute of Neurological Diseases and Stroke, National Institutes of HealthBethesdaUnited States
| | - Andrés Jara-Oseguera
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Diseases and Stroke, National Institutes of HealthBethesdaUnited States
| | - Lucy R Forrest
- Computational Structural Biology Section, Porter Neuroscience Research Center, National Institute of Neurological Diseases and Stroke, National Institutes of HealthBethesdaUnited States
| | - Kenton J Swartz
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Diseases and Stroke, National Institutes of HealthBethesdaUnited States
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Sarti E, Aleksandrova AA, Ganta SK, Yavatkar AS, Forrest LR. EncoMPASS: an online database for analyzing structure and symmetry in membrane proteins. Nucleic Acids Res 2020; 47:D315-D321. [PMID: 30357403 PMCID: PMC6323976 DOI: 10.1093/nar/gky952] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 10/05/2018] [Indexed: 12/21/2022] Open
Abstract
The EncoMPASS online database (http://encompass.ninds.nih.gov) collects, organizes, and presents information about membrane proteins of known structure, emphasizing their structural similarities as well as their quaternary and internal symmetries. Unlike, e.g. SCOP, the EncoMPASS database does not aim for a strict classification of membrane proteins, but instead is organized as a protein chain-centric network of sequence and structural homologues. The online server for the EncoMPASS database provides tools for comparing the structural features of its entries, making it a useful resource for homology modeling and active site identification studies. The database can also be used for inferring functionality, which for membrane proteins often involves symmetry-related mechanisms. To this end, the online database also provides a comprehensive description of both the quaternary and internal symmetries in known membrane protein structures, with a particular focus on their orientation relative to the membrane.
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Affiliation(s)
- Edoardo Sarti
- Computational Structural Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Antoniya A Aleksandrova
- Computational Structural Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Srujan K Ganta
- Bioinformatics Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Amarendra S Yavatkar
- Bioinformatics Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lucy R Forrest
- Computational Structural Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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Youkharibache P. Protodomains: Symmetry-Related Supersecondary Structures in Proteins and Self-Complementarity. Methods Mol Biol 2019; 1958:187-219. [PMID: 30945220 PMCID: PMC8323591 DOI: 10.1007/978-1-4939-9161-7_10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We will consider in this chapter supersecondary structures (SSS) as a set of secondary structure elements (SSEs) found in protein domains. Some SSS arrangements/topologies have been consistently observed within known tertiary structural domains. We use them in the context of repeating supersecondary structures that self-assemble in a symmetric arrangement to form a domain. We call them protodomains (or protofolds). Protodomains are some of the most interesting and insightful SSSs. Within a given 3D protein domain/fold, recognizing such sets may give insights into a possible evolutionary process of duplication, fusion, and coevolution of these protodomains, pointing to possible original protogenes. On protein folding itself, pseudosymmetric domains may point to a "directed" assembly of pseudosymmetric protodomains, directed by the only fact that they are tethered together in a protein chain. On function, tertiary functional sites often occur at protodomain interfaces, as they often occur at domain-domain interfaces in quaternary arrangements.First, we will briefly review some lessons learned from a previously published census of pseudosymmetry in protein domains (Myers-Turnbull, D. et al., J Mol Biol. 426:2255-2268, 2014) to introduce protodomains/protofolds. We will observe that the most abundant and diversified folds, or superfolds, in the currently known protein structure universe are indeed pseudosymmetric. Then, we will learn by example and select a few domain representatives of important pseudosymmetric folds and chief among them the immunoglobulin (Ig) fold and go over a pseudosymmetry supersecondary structure (protodomain) analysis in tertiary and quaternary structures. We will point to currently available software tools to help in identifying pseudosymmetry, delineating protodomains, and see how the study of pseudosymmetry and the underlying supersecondary structures can enrich a structural analysis. This should potentially help in protein engineering, especially in the development of biologics and immunoengineering.
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Computational design of ligand-binding membrane receptors with high selectivity. Nat Chem Biol 2017; 13:715-723. [PMID: 28459439 PMCID: PMC5478435 DOI: 10.1038/nchembio.2371] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 02/02/2017] [Indexed: 12/13/2022]
Abstract
Accurate modeling and design of protein-ligand
interactions have broad applications in cell, synthetic
biology and drug discovery but remain challenging without
experimental protein structures. Here we developed an
integrated protein homology modeling-ligand docking-protein
design approach that reconstructs protein-ligand binding
sites from homolog protein structures in the presence of
protein-bound ligand poses to capture conformational
selection and induced fit modes of ligand binding. In
structure modeling tests, we blindly predicted near-atomic
accuracy ligand conformations bound to G protein-coupled
receptors (GPCRs) that were rarely identified by traditional
approaches. We also quantitatively predicted the binding
selectivity of diverse ligands to
structurally-uncharacterized GPCRs. We then applied the
technique to design functional human dopamine receptors with
novel ligand binding selectivity. Most blindly predicted
ligand binding specificities closely agreed with
experimental validations. Our method should prove useful in
ligand discovery approaches and in reprogramming the ligand
binding profile of membrane receptors that remain difficult
to crystallize.
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Vergara-Jaque A, Fenollar-Ferrer C, Mulligan C, Mindell JA, Forrest LR. Family resemblances: A common fold for some dimeric ion-coupled secondary transporters. ACTA ACUST UNITED AC 2016; 146:423-34. [PMID: 26503722 PMCID: PMC4621753 DOI: 10.1085/jgp.201511481] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The structures of two bacterial antiporters that act as multidrug resistance efflux pumps, MtrF and YdaH, resemble each other and that of the sodium-coupled succinate symporter VcINDY. Membrane transporter proteins catalyze the passage of a broad range of solutes across cell membranes, allowing the uptake and efflux of crucial compounds. Because of the difficulty of expressing, purifying, and crystallizing integral membrane proteins, relatively few transporter structures have been elucidated to date. Although every membrane transporter has unique characteristics, structural and mechanistic similarities between evolutionarily diverse transporters have been identified. Here, we compare two recently reported structures of membrane proteins that act as antimicrobial efflux pumps, namely MtrF from Neisseria gonorrhoeae and YdaH from Alcanivorax borkumensis, both with each other and with the previously published structure of a sodium-dependent dicarboxylate transporter from Vibrio cholerae, VcINDY. MtrF and YdaH belong to the p-aminobenzoyl-glutamate transporter (AbgT) family and have been reported as having architectures distinct from those of all other families of transporters. However, our comparative analysis reveals a similar structural arrangement in all three proteins, with highly conserved secondary structure elements. Despite their differences in biological function, the overall “design principle” of MtrF and YdaH appears to be almost identical to that of VcINDY, with a dimeric quaternary structure, helical hairpins, and clear boundaries between the transport and scaffold domains. This observation demonstrates once more that the same secondary transporter architecture can be exploited for multiple distinct transport modes, including cotransport and antiport. Based on our comparisons, we detected conserved motifs in the substrate-binding region and predict specific residues likely to be involved in cation or substrate binding. These findings should prove useful for the future characterization of the transport mechanisms of these families of secondary active transporters.
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Affiliation(s)
- Ariela Vergara-Jaque
- Computational Structural Biology Unit and Membrane Transport Biophysics Section, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20824
| | - Cristina Fenollar-Ferrer
- Computational Structural Biology Unit and Membrane Transport Biophysics Section, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20824
| | - Christopher Mulligan
- Computational Structural Biology Unit and Membrane Transport Biophysics Section, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20824
| | - Joseph A Mindell
- Computational Structural Biology Unit and Membrane Transport Biophysics Section, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20824
| | - Lucy R Forrest
- Computational Structural Biology Unit and Membrane Transport Biophysics Section, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20824
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