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Neuberger A, Shalygin A, Trofimov YA, Veretenenko II, Nadezhdin KD, Krylov NA, Gudermann T, Efremov RG, Chubanov V, Sobolevsky AI. Structure-function analyses of human TRPV6 ancestral and derived haplotypes. Structure 2025; 33:91-103.e5. [PMID: 39500315 PMCID: PMC11698656 DOI: 10.1016/j.str.2024.10.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2024] [Revised: 09/29/2024] [Accepted: 10/09/2024] [Indexed: 12/12/2024]
Abstract
TRPV6 is a Ca2+ selective channel that mediates calcium uptake in the gut and contributes to the development and progression of human cancers. TRPV6 is represented by the ancestral and derived haplotypes that differ by three non-synonymous polymorphisms, located in the N-terminal ankyrin repeat domain (C157R), S1-S2 extracellular loop (M378V), and C-terminus (M681T). The ancestral and derived haplotypes were proposed to serve as genomic factors causing a different outcome for cancer patients of African ancestry. We solved cryoelectron microscopy (cryo-EM) structures of ancestral and derived TRPV6 in the open and calmodulin (CaM)-bound inactivated states. Neither state shows substantial structural differences caused by the non-synonymous polymorphisms. Functional properties assessed by electrophysiological recordings and Ca2+ uptake measurements, and water and ion permeation evaluated by molecular modeling also appear similar between the haplotypes. Therefore, ancestral and derived TRPV6 have similar structure and function, implying that other factors are responsible for the differences in susceptibility to cancer.
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Affiliation(s)
- Arthur Neuberger
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Alexey Shalygin
- Walther-Straub Institute of Pharmacology and Toxicology, LMU Munich, 80336 Munich, Germany
| | - Yury A Trofimov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Irina I Veretenenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Kirill D Nadezhdin
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Nikolay A Krylov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Thomas Gudermann
- Walther-Straub Institute of Pharmacology and Toxicology, LMU Munich, 80336 Munich, Germany; Comprehensive Pneumology Center, German Center for Lung Research, 81377 Munich, Germany
| | - Roman G Efremov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; National Research University Higher School of Economics, 101000 Moscow, Russia
| | - Vladimir Chubanov
- Walther-Straub Institute of Pharmacology and Toxicology, LMU Munich, 80336 Munich, Germany
| | - Alexander I Sobolevsky
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
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2
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Stafin K, Śliwa P, Pia Tkowski M, Matýsek D. Chitosan as a Templating Agent of Calcium Phosphate Crystalline Phases in Biomimetic Mineralization: Theoretical and Experimental Studies. ACS APPLIED MATERIALS & INTERFACES 2024; 16:63155-63169. [PMID: 39526983 DOI: 10.1021/acsami.4c11887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2024]
Abstract
Highlighting the essential role of chitosan (CS), known for its biocompatibility, biodegradability, and ability to promote cell adhesion and proliferation, this study explores its utility in modulating the biomimetic mineralization of calcium phosphate (CaP). This approach holds promise for developing biomaterials suitable for bone regeneration. However, the interactions between the CS surface and in situ precipitated CaP still require further exploration. In the theoretical section, molecular dynamics (MD) simulations demonstrate that, at an appropriate pH level during the prenucleation stage, calcium ions (Ca2+) and hydrogen phosphate ions (HPO42-) form Posner-like clusters. Additionally, the interaction between these clusters and the CS molecule enhances system stability. Together, these phenomena facilitate the transition to subsequent heterogeneous nucleation on the surface of the organic matrix, which is a more controlled process than homogeneous nucleation in solution. Dynamic simulation results suggest that CS acts as a stabilizing matrix at pH 8.0 during biomimetic mineralization. In the experimental section, the effects of pH and the molecular weight of CS were investigated, with a focus on their impact on the crystal structure of the resulting material. X-ray diffraction and scanning electron microscopy analyses reveal that, under conditions of approximately pH 8.0 and a CS molecular weight of 20 000 g/mol, and controlled ion concentration, ultrasound radiation, and temperature, the dominant CaP phases in the material are carbonate-doped hydroxyapatite (CHA) and octacalcium phosphate (OCP). These findings suggest that CS, when adjusted for molecular weight and pH, facilitates the formation of CaP crystal phases that closely resemble the natural inorganic composition of bone, highlighting its protective and regulatory roles in the growth and maturation of crystals during mineralization. The theoretical predictions and experimental outcomes confirm the crucial role of CS as a templating agent, enabling the development of a biomimetic mineralization pathway. CS's ability to guide this process may prove valuable in the design of materials for bone tissue engineering, particularly in developing effective materials for bone tissue healing and regeneration.
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Affiliation(s)
- Krzysztof Stafin
- Department of Organic Chemistry and Technology, Faculty of Chemical Engineering and Technology, Cracow University of Technology, ul. Warszawska 24, 31-155 Kraków, Poland
- Department of Biotechnology and Physical Chemistry, Faculty of Chemical Engineering and Technology, Cracow University of Technology, ul. Warszawska 24, 31-155 Kraków, Poland
| | - Paweł Śliwa
- Department of Organic Chemistry and Technology, Faculty of Chemical Engineering and Technology, Cracow University of Technology, ul. Warszawska 24, 31-155 Kraków, Poland
| | - Marek Pia Tkowski
- Department of Biotechnology and Physical Chemistry, Faculty of Chemical Engineering and Technology, Cracow University of Technology, ul. Warszawska 24, 31-155 Kraków, Poland
| | - Dalibor Matýsek
- Faculty of Mining and Geology, Technical University of Ostrava, 708 00 Ostrava, Czech Republic
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3
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Cao Y, Jin D, Kampf N, Klein J. Origins of synergy in multilipid lubrication. Proc Natl Acad Sci U S A 2024; 121:e2408223121. [PMID: 39531494 PMCID: PMC11588124 DOI: 10.1073/pnas.2408223121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Accepted: 10/03/2024] [Indexed: 11/16/2024] Open
Abstract
Lipid bilayers, ubiquitous in living systems, form lubricious boundary layers in aqueous media, with broad relevance for biolubrication, especially in mechanically stressed environments such as articular cartilage in joints, as well as for modifying material interfacial properties. Model studies have revealed efficient lubricity by single-component lipid bilayers; synovial joints, however (e.g. hips and knees), comprise over a hundred different lipids, raising the question of whether this is natural redundancy or whether it confers any lubrication benefits. Here, we examine lubrication by progressively more complex mixtures of lipids representative of those in joints, using a surface forces balance at physiologically relevant salt concentrations and pressures. We find that different combinations of such lipids differ very significantly in the robustness of the bilayers to hemifusion under physiological loads (when lubrication breaks down), indicating a clear lubrication synergy afforded by multiple lipid types in the bilayers. Insight into the origins of this synergy is provided by detailed molecular dynamics simulations of potential profiles for the formation of stalks, the essential precursors of hemifusion, between bilayers of the different lipid mixtures used in the experiments. These reveal how bilayer hemifusion-and thus lubrication breakdown-depends on the detailed lipid bilayer composition, through the corresponding separation into domains that are better able to resist stalk formation. Our results shed light on the role of lipid-type proliferation in biolubrication synergy, point to improved treatment modalities for common joint diseases such as osteoarthritis, and indicate how lipid-based interfacial modification in a materials context may be optimized.
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Affiliation(s)
- Yifeng Cao
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot76100, Israel
| | - Di Jin
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot76100, Israel
| | - Nir Kampf
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot76100, Israel
| | - Jacob Klein
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot76100, Israel
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4
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Huang J, Pan X, Yan N. Structural biology and molecular pharmacology of voltage-gated ion channels. Nat Rev Mol Cell Biol 2024; 25:904-925. [PMID: 39103479 DOI: 10.1038/s41580-024-00763-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2024] [Indexed: 08/07/2024]
Abstract
Voltage-gated ion channels (VGICs), including those for Na+, Ca2+ and K+, selectively permeate ions across the cell membrane in response to changes in membrane potential, thus participating in physiological processes involving electrical signalling, such as neurotransmission, muscle contraction and hormone secretion. Aberrant function or dysregulation of VGICs is associated with a diversity of neurological, psychiatric, cardiovascular and muscular disorders, and approximately 10% of FDA-approved drugs directly target VGICs. Understanding the structure-function relationship of VGICs is crucial for our comprehension of their working mechanisms and role in diseases. In this Review, we discuss how advances in single-particle cryo-electron microscopy have afforded unprecedented structural insights into VGICs, especially on their interactions with clinical and investigational drugs. We present a comprehensive overview of the recent advances in the structural biology of VGICs, with a focus on how prototypical drugs and toxins modulate VGIC activities. We explore how these structures elucidate the molecular basis for drug actions, reveal novel pharmacological sites, and provide critical clues to future drug discovery.
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Affiliation(s)
- Jian Huang
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Xiaojing Pan
- Institute of Bio-Architecture and Bio-Interactions (IBABI), Shenzhen Medical Academy of Research and Translation (SMART), Shenzhen, Guangdong, China.
| | - Nieng Yan
- Institute of Bio-Architecture and Bio-Interactions (IBABI), Shenzhen Medical Academy of Research and Translation (SMART), Shenzhen, Guangdong, China.
- Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, State Key Laboratory of Membrane Biology, Tsinghua University, Beijing, China.
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5
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Török F, Salamon S, Ortner NJ, Fernández-Quintero ML, Matthes J, Striessnig J. Inactivation induced by pathogenic Ca v1.3 L-type Ca 2+-channel variants enhances sensitivity for dihydropyridine Ca 2+ channel blockers. Br J Pharmacol 2024. [PMID: 39370994 DOI: 10.1111/bph.17357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 08/12/2024] [Accepted: 09/02/2024] [Indexed: 10/08/2024] Open
Abstract
BACKGROUND AND PURPOSE Pathogenic gain-of-function mutations in Cav1.3 L-type voltage-gated Ca2+-channels (CACNA1D) cause neurodevelopmental disorders with or without endocrine symptoms. We aimed to confirm a pathogenic gain-of function phenotype of CACNA1D de novo missense mutations A749T and L271H, and investigated the molecular mechanism causing their enhanced sensitivity for the Ca2+-channel blocker isradipine, a potential therapeutic for affected patients. EXPERIMENTAL APPROACH Wildtype and mutant channels were expressed in tsA-201 cells and their gating analysed using whole-cell and single-channel patch-clamp recordings. The voltage-dependence of isradipine action was quantified using protocols inducing variable fractions of inactivated channels. The molecular basis for altered channel gating in the mutants was investigated using in silico modelling and molecular dynamics simulations. KEY RESULTS Both mutations were confirmed pathogenic due to characteristic shifts of voltage-dependent activation and inactivation towards negative potentials (~20 mV). At negative holding potentials both mutations showed significantly higher isradipine sensitivity compared to wildtype. The affinity for wildtype and mutant channels increased with channel inactivation as predicted by the modulated receptor hypothesis (30- to 40-fold). The IC50 was indistinguishable for wildtype and mutants when >50% of channels were inactivated. CONCLUSIONS AND IMPLICATIONS Mutations A749T and L271H induce pathogenic gating changes. Like wildtype, isradipine inhibition is strongly voltage-dependent. Our data explains their apparent higher drug sensitivity at a given negative voltage by the availability of more inactivated channels due to their more negative inactivation voltage range. Low nanomolar isradipine concentrations will only inhibit Cav1.3 channels in neurons during prolonged depolarized states without selectivity for mutant channels.
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Affiliation(s)
- Ferenc Török
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Sarah Salamon
- Center of Pharmacology, Institute II, University of Cologne, Cologne, Germany
| | - Nadine J Ortner
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Monica L Fernández-Quintero
- Department of General, Inorganic and Theoretical Chemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Jan Matthes
- Center of Pharmacology, Institute II, University of Cologne, Cologne, Germany
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
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6
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Klink BU, Alavizargar A, Kalyankumar KS, Chen M, Heuer A, Gatsogiannis C. Structural basis of α-latrotoxin transition to a cation-selective pore. Nat Commun 2024; 15:8551. [PMID: 39362850 PMCID: PMC11449929 DOI: 10.1038/s41467-024-52635-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Accepted: 09/16/2024] [Indexed: 10/05/2024] Open
Abstract
The potent neurotoxic venom of the black widow spider contains a cocktail of seven phylum-specific latrotoxins (LTXs), but only one, α-LTX, targets vertebrates. This 130 kDa toxin binds to receptors at presynaptic nerve terminals and triggers a massive release of neurotransmitters. It is widely accepted that LTXs tetramerize and insert into the presynaptic membrane, thereby forming Ca2+-conductive pores, but the underlying mechanism remains poorly understood. LTXs are homologous and consist of an N-terminal region with three distinct domains, along with a C-terminal domain containing up to 22 consecutive ankyrin repeats. Here we report cryoEM structures of the vertebrate-specific α-LTX tetramer in its prepore and pore state. Our structures, in combination with AlphaFold2-based structural modeling and molecular dynamics simulations, reveal dramatic conformational changes in the N-terminal region of the complex. Four distinct helical bundles rearrange and together form a highly stable, 15 nm long, cation-impermeable coiled-coil stalk. This stalk, in turn, positions an N-terminal pair of helices within the membrane, thereby enabling the assembly of a cation-permeable channel. Taken together, these data give insight into a unique mechanism for membrane insertion and channel formation, characteristic of the LTX family, and provide the necessary framework for advancing novel therapeutics and biotechnological applications.
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Affiliation(s)
- B U Klink
- Institute for Medical Physics and Biophysics, University Münster, Münster, Germany
- Center for Soft Nanoscience (SoN), University Münster, Münster, Germany
| | - A Alavizargar
- Center for Soft Nanoscience (SoN), University Münster, Münster, Germany
- Institute of Physical Chemistry, University of Münster, Münster, Germany
| | - K S Kalyankumar
- Institute for Medical Physics and Biophysics, University Münster, Münster, Germany
- Center for Soft Nanoscience (SoN), University Münster, Münster, Germany
| | - M Chen
- Institute for Medical Physics and Biophysics, University Münster, Münster, Germany
- Center for Soft Nanoscience (SoN), University Münster, Münster, Germany
| | - A Heuer
- Center for Soft Nanoscience (SoN), University Münster, Münster, Germany.
- Institute of Physical Chemistry, University of Münster, Münster, Germany.
| | - C Gatsogiannis
- Institute for Medical Physics and Biophysics, University Münster, Münster, Germany.
- Center for Soft Nanoscience (SoN), University Münster, Münster, Germany.
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7
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Ives CM, Şahin AT, Thomson NJ, Zachariae U. A hydrophobic funnel governs monovalent cation selectivity in the ion channel TRPM5. Biophys J 2024; 123:3304-3316. [PMID: 39086136 PMCID: PMC11480762 DOI: 10.1016/j.bpj.2024.07.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 06/18/2024] [Accepted: 07/25/2024] [Indexed: 08/02/2024] Open
Abstract
A key capability of ion channels is the facilitation of selective permeation of certain ionic species across cellular membranes at high rates. Due to their physiological significance, ion channels are of great pharmaceutical interest as drug targets. The polymodal signal-detecting transient receptor potential (TRP) superfamily of ion channels forms a particularly promising group of drug targets. While most members of this family permeate a broad range of cations including Ca2+, TRPM4 and TRPM5 are unique due to their strong monovalent selectivity and impermeability for divalent cations. Here, we investigated the mechanistic basis for their unique monovalent selectivity by in silico electrophysiology simulations of TRPM5. Our simulations reveal an unusual mechanism of cation selectivity, which is underpinned by the function of the central channel cavity alongside the selectivity filter. Our results suggest that a subtle hydrophobic barrier at the cavity entrance ("hydrophobic funnel") enables monovalent but not divalent cations to pass and occupy the cavity at physiologically relevant membrane voltages. Monovalent cations then permeate efficiently by a cooperative, distant knock-on mechanism between two binding regions in the extracellular pore vestibule and the central cavity. By contrast, divalent cations do not enter or interact favorably with the channel cavity due to its raised hydrophobicity. Hydrophilic mutations in the transition zone between the selectivity filter and the central channel cavity abolish the barrier for divalent cations, enabling both monovalent and divalent cations to traverse TRPM5.
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Affiliation(s)
- Callum M Ives
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Alp Tegin Şahin
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, United Kingdom; School of Medicine, University of St Andrews, St Andrews, United Kingdom
| | - Neil J Thomson
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Ulrich Zachariae
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, United Kingdom; Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, United Kingdom.
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8
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Pelizzari S, Heiss MC, Fernández-Quintero ML, El Ghaleb Y, Liedl KR, Tuluc P, Campiglio M, Flucher BE. Ca V1.1 voltage-sensing domain III exclusively controls skeletal muscle excitation-contraction coupling. Nat Commun 2024; 15:7440. [PMID: 39198449 PMCID: PMC11358481 DOI: 10.1038/s41467-024-51809-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 08/16/2024] [Indexed: 09/01/2024] Open
Abstract
Skeletal muscle contractions are initiated by action potentials, which are sensed by the voltage-gated calcium channel (CaV1.1) and are conformationally coupled to calcium release from intracellular stores. Notably, CaV1.1 contains four separate voltage-sensing domains (VSDs), which activate channel gating and excitation-contraction (EC-) coupling at different voltages and with distinct kinetics. Here we show that a single VSD of CaV1.1 controls skeletal muscle EC-coupling. Whereas mutations in VSDs I, II and IV affect the current properties but not EC-coupling, only mutations in VSD III alter the voltage-dependence of depolarization-induced calcium release. Molecular dynamics simulations reveal comprehensive, non-canonical state transitions of VSD III in response to membrane depolarization. Identifying the voltage sensor that activates EC-coupling and detecting its unique conformational changes opens the door to unraveling the downstream events linking VSD III motion to the opening of the calcium release channel, and thus resolving the signal transduction mechanism of skeletal muscle EC-coupling.
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Affiliation(s)
- Simone Pelizzari
- Institute of Physiology, Department of Physiology and Medical Biophysics, Medical University Innsbruck, 6020, Innsbruck, Austria
| | - Martin C Heiss
- Institute of Physiology, Department of Physiology and Medical Biophysics, Medical University Innsbruck, 6020, Innsbruck, Austria
| | | | - Yousra El Ghaleb
- Institute of Physiology, Department of Physiology and Medical Biophysics, Medical University Innsbruck, 6020, Innsbruck, Austria
| | - Klaus R Liedl
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Petronel Tuluc
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020, Innsbruck, Austria
| | - Marta Campiglio
- Institute of Physiology, Department of Physiology and Medical Biophysics, Medical University Innsbruck, 6020, Innsbruck, Austria
| | - Bernhard E Flucher
- Institute of Physiology, Department of Physiology and Medical Biophysics, Medical University Innsbruck, 6020, Innsbruck, Austria.
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9
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Chakraborty S, Feng Z, Lee S, Alvarenga OE, Panda A, Bruni R, Khelashvili G, Gupta K, Accardi A. Structure and function of the human apoptotic scramblase Xkr4. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.07.607004. [PMID: 39149361 PMCID: PMC11326236 DOI: 10.1101/2024.08.07.607004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Phosphatidylserine externalization on the surface of dying cells is a key signal for their recognition and clearance by macrophages and is mediated by members of the X-Kell related (Xkr) protein family. Defective Xkr-mediated scrambling impairs clearance, leading to inflammation. It was proposed that activation of the Xkr4 apoptotic scramblase requires caspase cleavage, followed by dimerization and ligand binding. Here, using a combination of biochemical approaches we show that purified monomeric, full-length human Xkr4 (hXkr4) scrambles lipids. CryoEM imaging shows that hXkr4 adopts a novel conformation, where three conserved acidic residues create an electronegative surface embedded in the membrane. Molecular dynamics simulations show this conformation induces membrane thinning, which could promote scrambling. Thinning is ablated or reduced in conditions where scrambling is abolished or reduced. Our work provides insights into the molecular mechanisms of hXkr4 scrambling and suggests the ability to thin membranes might be a general property of active scramblases.
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Affiliation(s)
| | - Zhang Feng
- Department of Anesthesiology, Weill Cornell Medical College
| | - Sangyun Lee
- Department of Anesthesiology, Weill Cornell Medical College
| | - Omar E. Alvarenga
- Physiology, Biophysics and Systems Biology Graduate Program, Weill Cornell Medical College
| | - Aniruddha Panda
- Nanobiology Institute, Yale University, West Haven, Connecticut 06516, United States
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520, United States
| | - Renato Bruni
- Center on Membrane Protein Production and Analysis (COMPPÅ), New York Structural Biology Center, New York, NY 10027, USA
| | | | - Kallol Gupta
- Nanobiology Institute, Yale University, West Haven, Connecticut 06516, United States
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520, United States
| | - Alessio Accardi
- Department of Anesthesiology, Weill Cornell Medical College
- Department of Physiology and Biophysics, Weill Cornell Medical College
- Department of Biochemistry, Weill Cornell Medical College
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10
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Gallino SL, Agüero L, Boffi JC, Schottlender G, Buonfiglio P, Dalamon V, Marcovich I, Carpaneto A, Craig PO, Plazas PV, Elgoyhen AB. Key role of the TM2-TM3 loop in calcium potentiation of the α9α10 nicotinic acetylcholine receptor. Cell Mol Life Sci 2024; 81:337. [PMID: 39120784 PMCID: PMC11335262 DOI: 10.1007/s00018-024-05381-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 07/09/2024] [Accepted: 07/23/2024] [Indexed: 08/10/2024]
Abstract
The α9α10 nicotinic cholinergic receptor (nAChR) is a ligand-gated pentameric cation-permeable ion channel that mediates synaptic transmission between descending efferent neurons and mechanosensory inner ear hair cells. When expressed in heterologous systems, α9 and α10 subunits can assemble into functional homomeric α9 and heteromeric α9α10 receptors. One of the differential properties between these nAChRs is the modulation of their ACh-evoked responses by extracellular calcium (Ca2+). While α9 nAChRs responses are blocked by Ca2+, ACh-evoked currents through α9α10 nAChRs are potentiated by Ca2+ in the micromolar range and blocked at millimolar concentrations. Using chimeric and mutant subunits, together with electrophysiological recordings under two-electrode voltage-clamp, we show that the TM2-TM3 loop of the rat α10 subunit contains key structural determinants responsible for the potentiation of the α9α10 nAChR by extracellular Ca2+. Moreover, molecular dynamics simulations reveal that the TM2-TM3 loop of α10 does not contribute to the Ca2+ potentiation phenotype through the formation of novel Ca2+ binding sites not present in the α9 receptor. These results suggest that the TM2-TM3 loop of α10 might act as a control element that facilitates the intramolecular rearrangements that follow ACh-evoked α9α10 nAChRs gating in response to local and transient changes of extracellular Ca2+ concentration. This finding might pave the way for the future rational design of drugs that target α9α10 nAChRs as otoprotectants.
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Affiliation(s)
- Sofia L Gallino
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ''Dr. Héctor N. Torres'' (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Lucía Agüero
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ''Dr. Héctor N. Torres'' (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Juan C Boffi
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ''Dr. Héctor N. Torres'' (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory, Monterotondo, Italy
| | - Gustavo Schottlender
- Instituto de Cálculo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Paula Buonfiglio
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ''Dr. Héctor N. Torres'' (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Viviana Dalamon
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ''Dr. Héctor N. Torres'' (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Irina Marcovich
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ''Dr. Héctor N. Torres'' (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Regeneron Pharmaceuticals, Inc. Tarrytown, 10591, NY, USA
| | - Agustín Carpaneto
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ''Dr. Héctor N. Torres'' (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Patricio O Craig
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
- Instituto de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (IQUIBICEN), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
| | - Paola V Plazas
- Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
| | - Ana B Elgoyhen
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ''Dr. Héctor N. Torres'' (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
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11
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Zaki AM, Çınaroğlu SS, Rahman T, Patel S, Biggin PC. Plasticity of the selectivity filter is essential for permeation in lysosomal TPC2 channels. Proc Natl Acad Sci U S A 2024; 121:e2320153121. [PMID: 39074274 PMCID: PMC11317647 DOI: 10.1073/pnas.2320153121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 06/24/2024] [Indexed: 07/31/2024] Open
Abstract
Two-pore channels are pathophysiologically important Na+- and Ca2+-permeable channels expressed in lysosomes and other acidic organelles. Unlike most other ion channels, their permeability is malleable and ligand-tuned such that when gated by the signaling lipid PI(3,5)P2, they are more Na+-selective than when gated by the Ca2+ mobilizing messenger nicotinic acid adenine dinucleotide phosphate. However, the structural basis that underlies such plasticity and single-channel behavior more generally remains poorly understood. A recent Cryo-electron microscopy (cryo-EM) structure of TPC2 bound to PI(3,5)P2 in a proposed open-channel conformation provided an opportunity to address this via molecular dynamics (MD) simulation. To our surprise, simulations designed to compute conductance through this structure revealed almost no Na+ permeation events even at very high transmembrane voltages. However further MD simulations identified a spontaneous transition to a dramatically different conformation of the selectivity filter that involved expansion and a flip in the orientation of two core asparagine residues. This alternative filter conformation was remarkably stable and allowed Na+ to flow through the channel leading to a conductance estimate that was in very good agreement with direct single-channel measurements. Furthermore, this conformation was more permeable for Na+ over Ca2+. Our results have important ramifications not just for understanding the control of ion selectivity in TPC2 channels but also more broadly in terms of how ion channels discriminate ions.
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Affiliation(s)
- Afroditi-Maria Zaki
- Department of Biochemistry, Structural Bioinformatics and Computational Biochemistry, University of Oxford, OxfordOX1 3QU, United Kingdom
| | - Süleyman Selim Çınaroğlu
- Department of Biochemistry, Structural Bioinformatics and Computational Biochemistry, University of Oxford, OxfordOX1 3QU, United Kingdom
| | - Taufiq Rahman
- Department of Pharmacology, University of Cambridge, CambridgeCB2 1PD, United Kingdom
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, LondonWC1E, 6BT, United Kingdom
| | - Philip C. Biggin
- Department of Biochemistry, Structural Bioinformatics and Computational Biochemistry, University of Oxford, OxfordOX1 3QU, United Kingdom
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12
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Ceccarelli M, Milenkovic S, Bodrenko IV. The Effect of Lipopolysaccharides on the Electrostatic Properties of Gram-Negative General Porins from Enterobacteriaceae. Chemphyschem 2024; 25:e202400147. [PMID: 38625051 DOI: 10.1002/cphc.202400147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/15/2024] [Accepted: 04/16/2024] [Indexed: 04/17/2024]
Abstract
We investigated, by using all-atom molecular dynamics simulations, the effect of the outer membrane of Gram-negative bacteria, composed in the outer leaflet by polar/charged lipopolysaccharides (LPS), on the electrostatic properties of general porins from the Enterobacteriaceae family. General porins constitute the main path for the facilitated diffusion of polar antibiotics through the outer membrane. As model system we selected OmpK36 from Klebsiella pneumoniae, the ortholog of OmpC from Escherichia coli. This species presents high variability of amino acid composition of porins, with the effect to increase its resistance to the penetration of antibiotics. The various properties we analyzed seem to indicate that LPS acts as an independent layer without affecting the internal electrostatic properties of OmpK36. The only apparent effect on the microsecond time scale we sampled is the appearance of calcium ions, when present at moderate concentration in solution, inside the pore. However, we noticed increased fluctuations of the polarization density and only minor changes on its average value.
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Affiliation(s)
- Matteo Ceccarelli
- Department of Physics, University of Cagliari, Cittadella Universitaria, 09042, Monserrato, IT
| | - Stefan Milenkovic
- Department of Physics, University of Cagliari, Cittadella Universitaria, 09042, Monserrato, IT
| | - Igor V Bodrenko
- Istituto Nanoscienze, CNR, piazza San Silvestro 12, 56127, Pisa, Italy
- Lab NEST, Scuola Normale Superiore, piazza San Silvestro 12, 56127, Pisa, Italy
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13
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Cubisino SAM, Milenkovic S, Conti-Nibali S, Musso N, Bonacci P, De Pinto V, Ceccarelli M, Reina S. Electrophysiological properties and structural prediction of the SARS-CoV-2 viroprotein E. Front Mol Biosci 2024; 11:1334819. [PMID: 38606285 PMCID: PMC11007222 DOI: 10.3389/fmolb.2024.1334819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 01/15/2024] [Indexed: 04/13/2024] Open
Abstract
COVID-19, the infectious disease caused by the most recently discovered coronavirus SARS- CoV-2, has caused millions of sick people and thousands of deaths all over the world. The viral positive-sense single-stranded RNA encodes 31 proteins among which the spike (S) is undoubtedly the best known. Recently, protein E has been reputed as a potential pharmacological target as well. It is essential for the assembly and release of the virions in the cell. Literature describes protein E as a voltage-dependent channel with preference towards monovalent cations whose intracellular expression, though, alters Ca2+ homeostasis and promotes the activation of the proinflammatory cascades. Due to the extremely high sequence identity of SARS-CoV-2 protein E (E-2) with the previously characterized E-1 (i.e., protein E from SARS-CoV) many data obtained for E-1 were simply adapted to the other. Recent solid state NMR structure revealed that the transmembrane domain (TMD) of E-2 self-assembles into a homo-pentamer, albeit the oligomeric status has not been validated with the full-length protein. Prompted by the lack of a common agreement on the proper structural and functional features of E-2, we investigated the specific mechanism/s of pore-gating and the detailed molecular structure of the most cryptic protein of SARS-CoV-2 by means of MD simulations of the E-2 structure and by expressing, refolding and analyzing the electrophysiological activity of the transmembrane moiety of the protein E-2, in its full length. Our results show a clear agreement between experimental and predictive studies and foresee a mechanism of activity based on Ca2+ affinity.
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Affiliation(s)
| | | | - Stefano Conti-Nibali
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Nicolò Musso
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Paolo Bonacci
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Vito De Pinto
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
- We.MitoBiotech S.R.L, Catania, Italy
| | | | - Simona Reina
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
- We.MitoBiotech S.R.L, Catania, Italy
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14
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Farci D, Milenkovic S, Iesu L, Tanas M, Ceccarelli M, Piano D. Structural characterization and functional insights into the type II secretion system of the poly-extremophile Deinococcus radiodurans. J Biol Chem 2024; 300:105537. [PMID: 38072042 PMCID: PMC10828601 DOI: 10.1016/j.jbc.2023.105537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 11/07/2023] [Accepted: 11/28/2023] [Indexed: 01/21/2024] Open
Abstract
The extremophile bacterium D. radiodurans boasts a distinctive cell envelope characterized by the regular arrangement of three protein complexes. Among these, the Type II Secretion System (T2SS) stands out as a pivotal structural component. We used cryo-electron microscopy to reveal unique features, such as an unconventional protein belt (DR_1364) around the main secretin (GspD), and a cap (DR_0940) found to be a separated subunit rather than integrated with GspD. Furthermore, a novel region at the N-terminus of the GspD constitutes an additional second gate, supplementing the one typically found in the outer membrane region. This T2SS was found to contribute to envelope integrity, while also playing a role in nucleic acid and nutrient trafficking. Studies on intact cell envelopes show a consistent T2SS structure repetition, highlighting its significance within the cellular framework.
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Affiliation(s)
- Domenica Farci
- Department of Plant Physiology, Warsaw University of Life Sciences - SGGW, Warsaw, Poland; Department of Life and Environmental Sciences, Università degli Studi di Cagliari, Cagliari, Italy; R&D Department, ReGenFix Laboratories, Sardara, Italy.
| | - Stefan Milenkovic
- Department of Physics and IOM/CNR, Università degli Studi di Cagliari, Monserrato, Italy
| | - Luca Iesu
- Department of Life and Environmental Sciences, Università degli Studi di Cagliari, Cagliari, Italy
| | - Marta Tanas
- Department of Life and Environmental Sciences, Università degli Studi di Cagliari, Cagliari, Italy
| | - Matteo Ceccarelli
- Department of Physics and IOM/CNR, Università degli Studi di Cagliari, Monserrato, Italy
| | - Dario Piano
- Department of Plant Physiology, Warsaw University of Life Sciences - SGGW, Warsaw, Poland; Department of Life and Environmental Sciences, Università degli Studi di Cagliari, Cagliari, Italy; R&D Department, ReGenFix Laboratories, Sardara, Italy.
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15
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Liu C, Xue L, Song C. Calcium binding and permeation in TRPV channels: Insights from molecular dynamics simulations. J Gen Physiol 2023; 155:e202213261. [PMID: 37728593 PMCID: PMC10510737 DOI: 10.1085/jgp.202213261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 05/21/2023] [Accepted: 09/06/2023] [Indexed: 09/21/2023] Open
Abstract
Some calcium channels selectively permeate Ca2+, despite the high concentration of monovalent ions in the surrounding environment, which is essential for many physiological processes. Without atomistic and dynamical ion permeation details, the underlying mechanism of Ca2+ selectivity has long been an intensively studied, yet controversial, topic. This study takes advantage of the homologous Ca2+-selective TRPV6 and non-selective TRPV1 and utilizes the recently solved open-state structures and a newly developed multisite calcium model to investigate the ion binding and permeation features in TRPV channels by molecular dynamics simulations. Our results revealed that the open-state TRPV6 and TRPV1 show distinct ion binding patterns in the selectivity filter, which lead to different ion permeation features. Two Ca2+ ions simultaneously bind to the selectivity filter of TRPV6 compared with only one Ca2+ in the case of TRPV1. Multiple Ca2+ binding at the selectivity filter of TRPV6 permeated in a concerted manner, which could efficiently block the permeation of Na+. Cations of various valences differentiate between the binding sites at the entrance of the selectivity filter in TRPV6. Ca2+ preferentially binds to the central site with a higher probability of permeation, repelling Na+ to a peripheral site. Therefore, we believe that ion binding competition at the selectivity filter of calcium channels, including the binding strength and number of binding sites, determines Ca2+ selectivity under physiological conditions.
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Affiliation(s)
- Chunhong Liu
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Lingfeng Xue
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Chen Song
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
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16
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Gao S, Yao X, Chen J, Huang G, Fan X, Xue L, Li Z, Wu T, Zheng Y, Huang J, Jin X, Wang Y, Wang Z, Yu Y, Liu L, Pan X, Song C, Yan N. Structural basis for human Ca v1.2 inhibition by multiple drugs and the neurotoxin calciseptine. Cell 2023; 186:5363-5374.e16. [PMID: 37972591 DOI: 10.1016/j.cell.2023.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 03/16/2023] [Accepted: 10/04/2023] [Indexed: 11/19/2023]
Abstract
Cav1.2 channels play crucial roles in various neuronal and physiological processes. Here, we present cryo-EM structures of human Cav1.2, both in its apo form and in complex with several drugs, as well as the peptide neurotoxin calciseptine. Most structures, apo or bound to calciseptine, amlodipine, or a combination of amiodarone and sofosbuvir, exhibit a consistent inactivated conformation with a sealed gate, three up voltage-sensing domains (VSDs), and a down VSDII. Calciseptine sits on the shoulder of the pore domain, away from the permeation path. In contrast, when pinaverium bromide, an antispasmodic drug, is inserted into a cavity reminiscent of the IFM-binding site in Nav channels, a series of structural changes occur, including upward movement of VSDII coupled with dilation of the selectivity filter and its surrounding segments in repeat III. Meanwhile, S4-5III merges with S5III to become a single helix, resulting in a widened but still non-conductive intracellular gate.
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Affiliation(s)
- Shuai Gao
- Department of Urology, Zhongnan Hospital of Wuhan University, TaiKang Center for Life and Medical Sciences, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
| | - Xia Yao
- Department of Urology, Zhongnan Hospital of Wuhan University, TaiKang Center for Life and Medical Sciences, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Jiaofeng Chen
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Center for Life Sciences, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Gaoxingyu Huang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Institute of Biology, Westlake Institute for Advanced Study, Zhejiang Provincial Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China
| | - Xiao Fan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Lingfeng Xue
- Center for Quantitative Biology, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Zhangqiang Li
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Center for Life Sciences, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Tong Wu
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Center for Life Sciences, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yupeng Zheng
- Tsinghua-Peking Center for Life Sciences, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Jian Huang
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Xueqin Jin
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Center for Life Sciences, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yan Wang
- Department of Biological Sciences, St. John's University, Queens, NY 11439, USA
| | - Zhifei Wang
- Department of Biological Sciences, St. John's University, Queens, NY 11439, USA
| | - Yong Yu
- Department of Biological Sciences, St. John's University, Queens, NY 11439, USA
| | - Lei Liu
- Tsinghua-Peking Center for Life Sciences, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Xiaojing Pan
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Center for Life Sciences, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Shenzhen Medical Academy of Research and Translation, Shenzhen, Guangdong 518107, China
| | - Chen Song
- Center for Quantitative Biology, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.
| | - Nieng Yan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Center for Life Sciences, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Shenzhen Medical Academy of Research and Translation, Shenzhen, Guangdong 518107, China.
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17
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Çınaroğlu S, Biggin PC. Computed Protein-Protein Enthalpy Signatures as a Tool for Identifying Conformation Sampling Problems. J Chem Inf Model 2023; 63:6095-6108. [PMID: 37759363 PMCID: PMC10565830 DOI: 10.1021/acs.jcim.3c01041] [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: 07/10/2023] [Indexed: 09/29/2023]
Abstract
Understanding the thermodynamic signature of protein-peptide binding events is a major challenge in computational chemistry. The complexity generated by both components possessing many degrees of freedom poses a significant issue for methods that attempt to directly compute the enthalpic contribution to binding. Indeed, the prevailing assumption has been that the errors associated with such approaches would be too large for them to be meaningful. Nevertheless, we currently have no indication of how well the present methods would perform in terms of predicting the enthalpy of binding for protein-peptide complexes. To that end, we carefully assembled and curated a set of 11 protein-peptide complexes where there is structural and isothermal titration calorimetry data available and then computed the absolute enthalpy of binding. The initial "out of the box" calculations were, as expected, very modest in terms of agreement with the experiment. However, careful inspection of the outliers allows for the identification of key sampling problems such as distinct conformations of peptide termini not being sampled or suboptimal cofactor parameters. Additional simulations guided by these aspects can lead to a respectable correlation with isothermal titration calorimetry (ITC) experiments (R2 of 0.88 and an RMSE of 1.48 kcal/mol overall). Although one cannot know prospectively whether computed ITC values will be correct or not, this work shows that if experimental ITC data are available, then this in conjunction with computed ITC, can be used as a tool to know if the ensemble being simulated is representative of the true ensemble or not. That is important for allowing the correct interpretation of the detailed dynamics of the system with respect to the measured enthalpy. The results also suggest that computational calorimetry is becoming increasingly feasible. We provide the data set as a resource for the community, which could be used as a benchmark to help further progress in this area.
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Affiliation(s)
| | - Philip C. Biggin
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, U.K.
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18
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Yan S, Ren X, Zheng L, Wang X, Liu T. A systematic analysis of residue and risk of cyantraniliprole in the water-sediment system: Does metabolism reduce its environmental risk? ENVIRONMENT INTERNATIONAL 2023; 179:108185. [PMID: 37688810 DOI: 10.1016/j.envint.2023.108185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 08/07/2023] [Accepted: 09/03/2023] [Indexed: 09/11/2023]
Abstract
As a representative variety of diamide insecticides, cyantraniliprole has broad application prospects. In this study, the fate and risk of cyantraniliprole and its main metabolite J9Z38 in a water-sediment system were investigated. The present result showed that more J9Z38 was adsorbed in the sediment at the end of exposure. However, the bioaccumulation capacity of cyantraniliprole in zebrafish was higher than that of J9Z38. Cyantraniliprole had stronger influence on the antioxidant system and detoxification system of zebrafish than J9Z38. Moreover, cyantraniliprole induced more significant oxidative stress effect and more differentially expressed genes (DEGs) in zebrafish. Cyantraniliprole had significantly influence on the expression of RyR-receptor-related genes, which was confirmed by resolving their binding modes with key receptor proteins using AlphaFold2 and molecular docking techniques. In the sediment, both cyantraniliprole and J9Z38 had inhibitory effects on microbial community structure diversity and metabolic function, especially cyantraniliprole. The methane metabolism pathway, mediated by methanogens such as Methanolinea, Methanoregula, and Methanosaeta, may be the main pathway of degradation of cyantraniliprole and J9Z38 in sediments. The present results demonstrated that metabolism can reduce the environmental risk of cyantraniliprole in water-sediment system to a certain extent.
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Affiliation(s)
- Saihong Yan
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xiangyu Ren
- Key Laboratory of Tobacco Pest Monitoring Controlling & Integrated Management, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Lei Zheng
- State Environmental Protection Key Laboratory of Dioxin Pollution, National Research Center of Environmental Analysis and Measurement, Sino-Japan Friendship Center for Environmental Protection, Beijing 100029, China.
| | - Xiuguo Wang
- Key Laboratory of Tobacco Pest Monitoring Controlling & Integrated Management, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Tong Liu
- Key Laboratory of Tobacco Pest Monitoring Controlling & Integrated Management, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China.
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19
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Zhang J, Song D, Schackert FK, Li J, Xiang S, Tian C, Gong W, Carloni P, Alfonso-Prieto M, Shi C. Fluoride permeation mechanism of the Fluc channel in liposomes revealed by solid-state NMR. SCIENCE ADVANCES 2023; 9:eadg9709. [PMID: 37611110 PMCID: PMC10446490 DOI: 10.1126/sciadv.adg9709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 07/21/2023] [Indexed: 08/25/2023]
Abstract
Solid-state nuclear magnetic resonance (ssNMR) methods can probe the motions of membrane proteins in liposomes at the atomic level and propel the understanding of biomolecular processes for which static structures cannot provide a satisfactory description. In this work, we report our study on the fluoride channel Fluc-Ec1 in phospholipid bilayers based on ssNMR and molecular dynamics simulations. Previously unidentified fluoride binding sites in the aqueous vestibules were experimentally verified by 19F-detected ssNMR. One of the two fluoride binding sites in the polar track was identified as a water molecule by 1H-detected ssNMR. Meanwhile, a dynamic hotspot at loop 1 was observed by comparing the spectra of wild-type Fluc-Ec1 in variant buffer conditions or with its mutants. Therefore, we propose that fluoride conduction in the Fluc channel occurs via a "water-mediated knock-on" permeation mechanism and that loop 1 is a key molecular determinant for channel gating.
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Affiliation(s)
- Jin Zhang
- Department of Neurosurgery, The First Affiliated Hospital of USTC, Center for BioAnalytical Chemistry, Hefei National Research Center for Interdisciplinary Sciences at the Microscale, University of Science and Technology of China, 230027 Hefei, P. R. China
| | - Dan Song
- Department of Neurosurgery, The First Affiliated Hospital of USTC, Center for BioAnalytical Chemistry, Hefei National Research Center for Interdisciplinary Sciences at the Microscale, University of Science and Technology of China, 230027 Hefei, P. R. China
| | - Florian Karl Schackert
- Institute for Advanced Simulations (IAS-5) and Institute of Neuroscience and Medicine (INM-9), Computational Biomedicine, Forschungszentrum Jülich, 52428 Jülich, Germany
- Department of Physics, RWTH Aachen University, 52074 Aachen, Germany
| | - Juan Li
- Department of Neurosurgery, The First Affiliated Hospital of USTC, Center for BioAnalytical Chemistry, Hefei National Research Center for Interdisciplinary Sciences at the Microscale, University of Science and Technology of China, 230027 Hefei, P. R. China
| | - Shengqi Xiang
- Department of Neurosurgery, The First Affiliated Hospital of USTC, Center for BioAnalytical Chemistry, Hefei National Research Center for Interdisciplinary Sciences at the Microscale, University of Science and Technology of China, 230027 Hefei, P. R. China
| | - Changlin Tian
- Department of Neurosurgery, The First Affiliated Hospital of USTC, Center for BioAnalytical Chemistry, Hefei National Research Center for Interdisciplinary Sciences at the Microscale, University of Science and Technology of China, 230027 Hefei, P. R. China
| | - Weimin Gong
- Department of Neurosurgery, The First Affiliated Hospital of USTC, Center for BioAnalytical Chemistry, Hefei National Research Center for Interdisciplinary Sciences at the Microscale, University of Science and Technology of China, 230027 Hefei, P. R. China
| | - Paolo Carloni
- Institute for Advanced Simulations (IAS-5) and Institute of Neuroscience and Medicine (INM-9), Computational Biomedicine, Forschungszentrum Jülich, 52428 Jülich, Germany
- Department of Physics, RWTH Aachen University, 52074 Aachen, Germany
| | - Mercedes Alfonso-Prieto
- Institute for Advanced Simulations (IAS-5) and Institute of Neuroscience and Medicine (INM-9), Computational Biomedicine, Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Chaowei Shi
- Department of Neurosurgery, The First Affiliated Hospital of USTC, Center for BioAnalytical Chemistry, Hefei National Research Center for Interdisciplinary Sciences at the Microscale, University of Science and Technology of China, 230027 Hefei, P. R. China
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20
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Yesylevskyy S, Martinez-Seara H, Jungwirth P. Curvature Matters: Modeling Calcium Binding to Neutral and Anionic Phospholipid Bilayers. J Phys Chem B 2023; 127:4523-4531. [PMID: 37191140 DOI: 10.1021/acs.jpcb.3c01962] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
In this work, the influence of membrane curvature on the Ca2+ binding to phospholipid bilayers is investigated by means of molecular dynamics simulations. In particular, we compared Ca2+ binding to flat, elastically buckled, or uniformly bent zwitterionic and anionic phospholipid bilayers. We demonstrate that Ca2+ ions bind preferably to the concave membrane surfaces in both types of bilayers. We also show that the membrane curvature leads to pronounced changes in Ca2+ binding including differences in free ion concentrations, lipid coordination distributions, and the patterns of ion binding to different chemical groups of lipids. Moreover, these effects differ substantially for the concave and convex membrane monolayers. Comparison between force fields with either full or scaled charges indicates that charge scaling results in reduction of the Ca2+ binding to curved phosphatidylserine bilayers, while for phosphatidylcholine membranes, calcium binds only weakly for both force fields.
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Affiliation(s)
- Semen Yesylevskyy
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 542/2, 160 00 Prague 6, Czech Republic
- Department of Physics of Biological Systems, Institute of Physics of the National Academy of Sciences of Ukraine, Nauky Avenue 46, 03038 Kyiv, Ukraine
- Receptor.AI Incorporated, 20-22 Wenlock Road, N1 7GU London, U.K
| | - Hector Martinez-Seara
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 542/2, 160 00 Prague 6, Czech Republic
| | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 542/2, 160 00 Prague 6, Czech Republic
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21
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Ives CM, Thomson NJ, Zachariae U. A cooperative knock-on mechanism underpins Ca2+-selective cation permeation in TRPV channels. J Gen Physiol 2023; 155:213957. [PMID: 36943243 PMCID: PMC10038842 DOI: 10.1085/jgp.202213226] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 11/15/2022] [Accepted: 02/28/2023] [Indexed: 03/23/2023] Open
Abstract
The selective exchange of ions across cellular membranes is a vital biological process. Ca2+-mediated signaling is implicated in a broad array of physiological processes in cells, while elevated intracellular concentrations of Ca2+ are cytotoxic. Due to the significance of this cation, strict Ca2+ concentration gradients are maintained across the plasma and organelle membranes. Therefore, Ca2+ signaling relies on permeation through selective ion channels that control the flux of Ca2+ ions. A key family of Ca2+-permeable membrane channels is the polymodal signal-detecting transient receptor potential (TRP) ion channels. TRP channels are activated by a wide variety of cues including temperature, small molecules, transmembrane voltage, and mechanical stimuli. While most members of this family permeate a broad range of cations non-selectively, TRPV5 and TRPV6 are unique due to their strong Ca2+ selectivity. Here, we address the question of how some members of the TRPV subfamily show a high degree of Ca2+ selectivity while others conduct a wider spectrum of cations. We present results from all-atom molecular dynamics simulations of ion permeation through two Ca2+-selective and two non-selective TRPV channels. Using a new method to quantify permeation cooperativity based on mutual information, we show that Ca2+-selective TRPV channel permeation occurs by a three-binding site knock-on mechanism, whereas a two-binding site knock-on mechanism is observed in non-selective TRPV channels. Each of the ion binding sites involved displayed greater affinity for Ca2+ over Na+. As such, our results suggest that coupling to an extra binding site in the Ca2+-selective TRPV channels underpins their increased selectivity for Ca2+ over Na+ ions. Furthermore, analysis of all available TRPV channel structures shows that the selectivity filter entrance region is wider for the non-selective TRPV channels, slightly destabilizing ion binding at this site, which is likely to underlie mechanistic decoupling.
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Affiliation(s)
- Callum M Ives
- Computational Biology, School of Life Sciences, University of Dundee , Dundee, UK
| | - Neil J Thomson
- Computational Biology, School of Life Sciences, University of Dundee , Dundee, UK
| | - Ulrich Zachariae
- Computational Biology, School of Life Sciences, University of Dundee , Dundee, UK
- Biochemistry and Drug Discovery, School of Life Sciences, University of Dundee , Dundee, UK
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22
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Chen Z, Watanabe S, Hashida H, Inoue M, Daigaku Y, Kikkawa M, Inaba K. Cryo-EM structures of human SPCA1a reveal the mechanism of Ca 2+/Mn 2+ transport into the Golgi apparatus. SCIENCE ADVANCES 2023; 9:eadd9742. [PMID: 36867705 PMCID: PMC9984183 DOI: 10.1126/sciadv.add9742] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 01/27/2023] [Indexed: 06/02/2023]
Abstract
Secretory pathway Ca2+/Mn2+ ATPase 1 (SPCA1) actively transports cytosolic Ca2+ and Mn2+ into the Golgi lumen, playing a crucial role in cellular calcium and manganese homeostasis. Detrimental mutations of the ATP2C1 gene encoding SPCA1 cause Hailey-Hailey disease. Here, using nanobody/megabody technologies, we determined cryo-electron microscopy structures of human SPCA1a in the ATP and Ca2+/Mn2+-bound (E1-ATP) state and the metal-free phosphorylated (E2P) state at 3.1- to 3.3-Å resolutions. The structures revealed that Ca2+ and Mn2+ share the same metal ion-binding pocket with similar but notably different coordination geometries in the transmembrane domain, corresponding to the second Ca2+-binding site in sarco/endoplasmic reticulum Ca2+-ATPase (SERCA). In the E1-ATP to E2P transition, SPCA1a undergoes similar domain rearrangements to those of SERCA. Meanwhile, SPCA1a shows larger conformational and positional flexibility of the second and sixth transmembrane helices, possibly explaining its wider metal ion specificity. These structural findings illuminate the unique mechanisms of SPCA1a-mediated Ca2+/Mn2+ transport.
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Affiliation(s)
- Zhenghao Chen
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi 980-8577, Japan
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Satoshi Watanabe
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi 980-8577, Japan
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8577, Japan
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Hironori Hashida
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi 980-8577, Japan
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Michio Inoue
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Yasukazu Daigaku
- Cancer Institute, Japanese Foundation for Cancer Research (JFCR), Tokyo 135-8550, Japan
| | - Masahide Kikkawa
- Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kenji Inaba
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi 980-8577, Japan
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8577, Japan
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Agency for Medical Research and Development (AMED), Tokyo, Japan
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23
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Schackert F, Biedermann J, Abdolvand S, Minniberger S, Song C, Plested AJR, Carloni P, Sun H. Mechanism of Calcium Permeation in a Glutamate Receptor Ion Channel. J Chem Inf Model 2023; 63:1293-1300. [PMID: 36758214 PMCID: PMC9976283 DOI: 10.1021/acs.jcim.2c01494] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Indexed: 02/11/2023]
Abstract
The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) are neurotransmitter-activated cation channels ubiquitously expressed in vertebrate brains. The regulation of calcium flux through the channel pore by RNA-editing is linked to synaptic plasticity while excessive calcium influx poses a risk for neurodegeneration. Unfortunately, the molecular mechanisms underlying this key process are mostly unknown. Here, we investigated calcium conduction in calcium-permeable AMPAR using Molecular Dynamics (MD) simulations with recently introduced multisite force-field parameters for Ca2+. Our calculations are consistent with experiment and explain the distinct calcium permeability in different RNA-edited forms of GluA2. For one of the identified metal binding sites, multiscale Quantum Mechanics/Molecular Mechanics (QM/MM) simulations further validated the results from MD and revealed small but reproducible charge transfer between the metal ion and its first solvation shell. In addition, the ion occupancy derived from MD simulations independently reproduced the Ca2+ binding profile in an X-ray structure of an NaK channel mimicking the AMPAR selectivity filter. This integrated study comprising X-ray crystallography, multisite MD, and multiscale QM/MM simulations provides unprecedented insights into Ca2+ permeation mechanisms in AMPARs, and paves the way for studying other biological processes in which Ca2+ plays a pivotal role.
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Affiliation(s)
- Florian
Karl Schackert
- Computational
Biomedicine (IAS-5/INM-9), Forschungszentrum
Jülich GmbH, 52428 Jülich, Germany
- Department
of Physics, RWTH Aachen University, 52062 Aachen, Germany
| | - Johann Biedermann
- Institute
of Biology, Cellular Biophysics, Humboldt
Universität zu Berlin, 10115 Berlin, Germany
- Leibniz
Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Saeid Abdolvand
- Institute
of Biology, Cellular Biophysics, Humboldt
Universität zu Berlin, 10115 Berlin, Germany
- Leibniz
Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Sonja Minniberger
- Institute
of Biology, Cellular Biophysics, Humboldt
Universität zu Berlin, 10115 Berlin, Germany
- Leibniz
Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Chen Song
- Center
for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
- Peking-Tsinghua
Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Andrew J. R. Plested
- Institute
of Biology, Cellular Biophysics, Humboldt
Universität zu Berlin, 10115 Berlin, Germany
- Leibniz
Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Paolo Carloni
- Computational
Biomedicine (IAS-5/INM-9), Forschungszentrum
Jülich GmbH, 52428 Jülich, Germany
- Department
of Physics, RWTH Aachen University, 52062 Aachen, Germany
| | - Han Sun
- Leibniz
Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany
- Institute
of Chemistry, TU Berlin, Straße des 17 Juni 135, 10623 Berlin, Germany
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24
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Newman KE, Khalid S. Conformational dynamics and putative substrate extrusion pathways of the N-glycosylated outer membrane factor CmeC from Campylobacter jejuni. PLoS Comput Biol 2023; 19:e1010841. [PMID: 36638139 PMCID: PMC9879487 DOI: 10.1371/journal.pcbi.1010841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 01/26/2023] [Accepted: 12/26/2022] [Indexed: 01/14/2023] Open
Abstract
The outer membrane factor CmeC of the efflux machinery CmeABC plays an important role in conferring antibiotic and bile resistance to Campylobacter jejuni. Curiously, the protein is N-glycosylated, with the glycans playing a key role in the effective function of this system. In this work we have employed atomistic equilibrium molecular dynamics simulations of CmeC in a representative model of the C. jejuni outer membrane to characterise the dynamics of the protein and its associated glycans. We show that the glycans are more conformationally labile than had previously been thought. The extracellular loops of CmeC visit the open and closed states freely suggesting the absence of a gating mechanism on this side, while the narrow periplasmic entrance remains tightly closed, regulated via coordination to solvated cations. We identify several cation binding sites on the interior surface of the protein. Additionally, we used steered molecular dynamics simulations to elucidate translocation pathways for a bile acid and a macrolide antibiotic. These, and additional equilibrium simulations suggest that the anionic bile acid utilises multivalent cations to climb the ladder of acidic residues that line the interior surface of the protein.
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Affiliation(s)
- Kahlan E. Newman
- School of Chemistry, University of Southampton, Southampton, United Kingdom
| | - Syma Khalid
- School of Chemistry, University of Southampton, Southampton, United Kingdom
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- * E-mail:
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25
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Zhuang Y, Noviello CM, Hibbs RE, Howard RJ, Lindahl E. Differential interactions of resting, activated, and desensitized states of the α7 nicotinic acetylcholine receptor with lipidic modulators. Proc Natl Acad Sci U S A 2022; 119:e2208081119. [PMID: 36251999 PMCID: PMC9618078 DOI: 10.1073/pnas.2208081119] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 09/08/2022] [Indexed: 11/18/2022] Open
Abstract
The α7 nicotinic acetylcholine receptor is a pentameric ligand-gated ion channel that modulates neuronal excitability, largely by allowing Ca2+ permeation. Agonist binding promotes transition from a resting state to an activated state, and then rapidly to a desensitized state. Recently, cryogenic electron microscopy (cryo-EM) structures of the human α7 receptor in nanodiscs were reported in multiple conformations. These were selectively stabilized by inhibitory, activating, or potentiating compounds. However, the functional annotation of these structures and their differential interactions with unresolved lipids and ligands remain incomplete. Here, we characterized their ion permeation, membrane interactions, and ligand binding using computational electrophysiology, free-energy calculations, and coarse-grained molecular dynamics. In contrast to nonconductive structures in apparent resting and desensitized states, the structure determined in the presence of the potentiator PNU-120596 was consistent with an activated state permeable to Ca2+. Transition to this state was associated with compression and rearrangement of the membrane, particularly in the vicinity of the peripheral MX helix. An intersubunit transmembrane site was implicated in selective binding of either PNU-120596 in the activated state or cholesterol in the desensitized state. This substantiates functional assignment of all three lipid-embedded α7-receptor structures with ion-permeation simulations. It also proposes testable models of their state-dependent interactions with lipophilic ligands, including a mechanism for allosteric modulation at the transmembrane subunit interface.
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Affiliation(s)
- Yuxuan Zhuang
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, PO Box 1031, Solna, 171 21 Sweden
| | - Colleen M. Noviello
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Ryan E. Hibbs
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Rebecca J. Howard
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, PO Box 1031, Solna, 171 21 Sweden
| | - Erik Lindahl
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, PO Box 1031, Solna, 171 21 Sweden
- Department of Applied Physics, Swedish e-Science Research Center, KTH Royal Institute of Technology, PO Box 1031, Solna, 171 21 Sweden
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26
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Basit A, Yadav AK, Bandyopadhyay P. Calcium Ion Binding to the Mutants of Calmodulin: A Structure-Based Computational Predictive Model of Binding Affinity Using a Charge Scaling Approach in Molecular Dynamics Simulation. J Chem Inf Model 2022; 62:2821-2834. [PMID: 35608259 DOI: 10.1021/acs.jcim.2c00428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The binding of calcium ions (Ca2+) to the calcium-binding proteins (CBPs) controls a plethora of regulatory processes. Among the roles played by CBPs in several diseases, the onset and progress of some cardiovascular diseases are caused by mutations in calmodulin (CaM), an important member of CBPs. Rationalization and prediction of the binding affinity of Ca2+ ions to the CaM can play important roles in understanding the origin of cardiovascular diseases. However, there is no robust structure-based computational method for predicting the binding affinity of Ca2+ ions to the different forms of CBPs in general and CaM in particular. In the current work, we have devised a fast yet accurate computational technique to accurately calculate the binding affinity of Ca2+ to the different forms of CaM. This method combines the well-known molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) method and a charge scaling approach developed by previous authors that takes care of the polarization of CaM and Ca2+ ions. Our detailed analysis of the different components of binding free energy shows that subtle changes in electrostatics and van der Waals contribute to the difference in the binding affinity of mutants from that of the wild type (WT), and the charge scaling approach is superior in calculating these subtle changes in electrostatics as compared to the nonpolarizable force field used in this work. A statistically significant regression model made from our binding free energy calculations gives a correlation coefficient close to 0.8 to the experimental results. This structure-based predictive model can open up a new strategy to understand and predict the binding of Ca2+ to the mutants of CBPs, in general.
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Affiliation(s)
- Abdul Basit
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Ajeet Kumar Yadav
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Pradipta Bandyopadhyay
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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27
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Tan Q, Ding Y, Qiu Z, Huang J. Binding Energy and Free Energy of Calcium Ion to Calmodulin EF-Hands with the Drude Polarizable Force Field. ACS PHYSICAL CHEMISTRY AU 2021; 2:143-155. [PMID: 36855509 PMCID: PMC9718305 DOI: 10.1021/acsphyschemau.1c00039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Calcium ions are important messenger molecules in cells, which bind calcium-binding proteins to trigger many biochemical processes. We constructed four model systems, each containing one EF-hand loop of calmodulin with one calcium ion bound, and investigated the binding energy and free energy of Ca2+ by the quantum mechanics symmetry-adapted perturbation theory (SAPT) method and the molecular mechanics with the additive CHARMM36m (C36m) and the polarizable Drude force fields (FFs). Our results show that the explicit introduction of polarizability in the Drude not only yields considerably improved agreement with the binding energy calculated from the SAPT method but is also able to capture each component of the binding energies including electrostatic, induction, exchange, and dispersion terms. However, binding free energies computed with the Drude and the C36m FFs both deviated significantly from the experimental measurements. Detailed analysis indicated that one of main reasons might be that the strong interactions between Ca2+ and the side chain nitrogen of Asn/Gln in the Drude FF caused the distorted coordination geometries of calcium. Our work illustrated the importance of polarization in modeling ion-protein interactions and the difficulty in generating accurate and balanced FF models to represent the polarization effects.
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Affiliation(s)
- Qiaozhu Tan
- College
of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China,Key
Laboratory of Structural Biology of Zhejiang Province, School of Life
Sciences, Westlake University, Hangzhou 310024, Zhejiang, China,Westlake
AI Therapeutics Lab, Westlake Laboratory
of Life Sciences and Biomedicine, Hangzhou 310024, Zhejiang, China
| | - Ye Ding
- College
of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China,Key
Laboratory of Structural Biology of Zhejiang Province, School of Life
Sciences, Westlake University, Hangzhou 310024, Zhejiang, China,Westlake
AI Therapeutics Lab, Westlake Laboratory
of Life Sciences and Biomedicine, Hangzhou 310024, Zhejiang, China
| | - Zongyang Qiu
- Key
Laboratory of Structural Biology of Zhejiang Province, School of Life
Sciences, Westlake University, Hangzhou 310024, Zhejiang, China,Westlake
AI Therapeutics Lab, Westlake Laboratory
of Life Sciences and Biomedicine, Hangzhou 310024, Zhejiang, China,Institute
of Biology, Westlake Institute for Advanced
Study, Hangzhou 310024, Zhejiang, China
| | - Jing Huang
- Key
Laboratory of Structural Biology of Zhejiang Province, School of Life
Sciences, Westlake University, Hangzhou 310024, Zhejiang, China,Westlake
AI Therapeutics Lab, Westlake Laboratory
of Life Sciences and Biomedicine, Hangzhou 310024, Zhejiang, China,Institute
of Biology, Westlake Institute for Advanced
Study, Hangzhou 310024, Zhejiang, China,
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28
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Zhang X, Yu H, Liu X, Song C. The Impact of Mutation L138F/L210F on the Orai Channel: A Molecular Dynamics Simulation Study. Front Mol Biosci 2021; 8:755247. [PMID: 34796201 PMCID: PMC8592927 DOI: 10.3389/fmolb.2021.755247] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 09/17/2021] [Indexed: 11/13/2022] Open
Abstract
The calcium release-activated calcium channel, composed of the Orai channel and the STIM protein, plays a crucial role in maintaining the Ca2+ concentration in cells. Previous studies showed that the L138F mutation in the human Orai1 creates a constitutively open channel independent of STIM, causing severe myopathy, but how the L138F mutation activates Orai1 is still unclear. Here, based on the crystal structure of Drosophila melanogaster Orai (dOrai), molecular dynamics simulations for the wild-type (WT) and the L210F (corresponding to L138F in the human Orai1) mutant were conducted to investigate their structural and dynamical properties. The results showed that the L210F dOrai mutant tends to have a more hydrated hydrophobic region (V174 to F171), as well as more dilated basic region (K163 to R155) and selectivity filter (E178). Sodium ions were located deeper in the mutant than in the wild-type. Further analysis revealed two local but essential conformational changes that may be the key to the activation. A rotation of F210, a previously unobserved feature, was found to result in the opening of the K163 gate through hydrophobic interactions. At the same time, a counter-clockwise rotation of F171 occurred more frequently in the mutant, resulting in a wider hydrophobic gate with more hydration. Ultimately, the opening of the two gates may facilitate the opening of the Orai channel independent of STIM.
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Affiliation(s)
- Xiaoqian Zhang
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,School of Physics, Shandong University, Jinan, China
| | - Hua Yu
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,College of Plant Protection, Shandong Agricultural University, Taian, China
| | - Xiangdong Liu
- School of Physics, Shandong University, Jinan, China
| | - Chen Song
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
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29
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Structural and energetic analysis of metastable intermediate states in the E1P-E2P transition of Ca 2+-ATPase. Proc Natl Acad Sci U S A 2021; 118:2105507118. [PMID: 34593638 PMCID: PMC8501872 DOI: 10.1073/pnas.2105507118] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/23/2021] [Indexed: 01/05/2023] Open
Abstract
Ion pumps (or P-type ATPases) are membrane proteins, which transport ions through biological membranes against a concentration gradient, a function essential for many biological processes, such as muscle contraction, neurotransmission, and metabolism. Molecular mechanisms underlying active ion transport by ion pumps have been investigated by biochemical experiments and high-resolution structure analyses. Here, the transition of sarcoplasmic reticulum Ca2+-ATPase upon dissociation of Ca2+ is investigated using atomistic molecular dynamics simulations. We find intermediate structures along the pathway are stabilized by transient interactions between A- and P-domains as well as lipid molecules in the transmembrane helices. Sarcoplasmic reticulum (SR) Ca2+-ATPase transports two Ca2+ ions from the cytoplasm to the SR lumen against a large concentration gradient. X-ray crystallography has revealed the atomic structures of the protein before and after the dissociation of Ca2+, while biochemical studies have suggested the existence of intermediate states in the transition between E1P⋅ADP⋅2Ca2+ and E2P. Here, we explore the pathway and free energy profile of the transition using atomistic molecular dynamics simulations with the mean-force string method and umbrella sampling. The simulations suggest that a series of structural changes accompany the ordered dissociation of ADP, the A-domain rotation, and the rearrangement of the transmembrane (TM) helices. The luminal gate then opens to release Ca2+ ions toward the SR lumen. Intermediate structures on the pathway are stabilized by transient sidechain interactions between the A- and P-domains. Lipid molecules between TM helices play a key role in the stabilization. Free energy profiles of the transition assuming different protonation states suggest rapid exchanges between Ca2+ ions and protons when the Ca2+ ions are released toward the SR lumen.
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30
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Natarajan K, Mukhtasimova N, Corradi J, Lasala M, Bouzat C, Sine SM. Mechanism of calcium potentiation of the α7 nicotinic acetylcholine receptor. J Gen Physiol 2021; 152:151971. [PMID: 32702089 PMCID: PMC7478872 DOI: 10.1085/jgp.202012606] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 05/19/2020] [Accepted: 06/22/2020] [Indexed: 12/14/2022] Open
Abstract
The α7 nicotinic acetylcholine receptor (nAChR) is among the most abundant types of nAChR in the brain, yet the ability of nerve-released ACh to activate α7 remains enigmatic. In particular, a major population of α7 resides in extra-synaptic regions where the ACh concentration is reduced, owing to dilution and enzymatic hydrolysis, yet ACh shows low potency in activating α7. Using high-resolution single-channel recording techniques, we show that extracellular calcium is a powerful potentiator of α7 activated by low concentrations of ACh. Potentiation manifests as robust increases in the frequency of channel opening and the average duration of the openings. Molecular dynamics simulations reveal that calcium binds to the periphery of the five ligand binding sites and is framed by a pair of anionic residues from the principal and complementary faces of each site. Mutation of residues identified by simulation prevents calcium from potentiating ACh-elicited channel opening. An anionic residue is conserved at each of the identified positions in all vertebrate species of α7. Thus, calcium associates with a novel structural motif on α7 and is an obligate cofactor in regions of limited ACh concentration.
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Affiliation(s)
- Kathiresan Natarajan
- Receptor Biology Laboratory, Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN
| | - Nuriya Mukhtasimova
- Receptor Biology Laboratory, Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN
| | - Jeremías Corradi
- Instituto de Investigaciones Bioquímicas, Departamento de Biologia, Bioquimica y Farmacia, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas, Bahía Blanca, Argentina
| | - Matías Lasala
- Instituto de Investigaciones Bioquímicas, Departamento de Biologia, Bioquimica y Farmacia, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas, Bahía Blanca, Argentina
| | - Cecilia Bouzat
- Instituto de Investigaciones Bioquímicas, Departamento de Biologia, Bioquimica y Farmacia, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas, Bahía Blanca, Argentina
| | - Steven M Sine
- Receptor Biology Laboratory, Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN.,Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN.,Department of Neurology, Mayo Clinic College of Medicine, Rochester, MN
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31
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Abstract
Fast excitatory synaptic transmission in the central nervous system relies on the AMPA-type glutamate receptor (AMPAR). This receptor incorporates a nonselective cation channel, which is opened by the binding of glutamate. Although the open pore structure has recently became available from cryo-electron microscopy (Cryo-EM), the molecular mechanisms governing cation permeability in AMPA receptors are not understood. Here, we combined microsecond molecular dynamic (MD) simulations on a putative open-state structure of GluA2 with electrophysiology on cloned channels to elucidate ion permeation mechanisms. Na+, K+, and Cs+ permeated at physiological rates, consistent with a structure that represents a true open state. A single major ion binding site for Na+ and K+ in the pore represents the simplest selectivity filter (SF) structure for any tetrameric cation channel of known structure. The minimal SF comprised only Q586 and Q587, and other residues on the cytoplasmic side formed a water-filled cavity with a cone shape that lacked major interactions with ions. We observed that Cl- readily enters the upper pore, explaining anion permeation in the RNA-edited (Q586R) form of GluA2. A permissive architecture of the SF accommodated different alkali metals in distinct solvation states to allow rapid, nonselective cation permeation and copermeation by water. Simulations suggested Cs+ uses two equally populated ion binding sites in the filter, and we confirmed with electrophysiology of GluA2 that Cs+ is slightly more permeant than Na+, consistent with serial binding sites preferentially driving selectivity.
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32
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Neville SL, Sjöhamn J, Watts JA, MacDermott-Opeskin H, Fairweather SJ, Ganio K, Carey Hulyer A, McGrath AP, Hayes AJ, Malcolm TR, Davies MR, Nomura N, Iwata S, O'Mara ML, Maher MJ, McDevitt CA. The structural basis of bacterial manganese import. SCIENCE ADVANCES 2021; 7:eabg3980. [PMID: 34362732 PMCID: PMC8346216 DOI: 10.1126/sciadv.abg3980] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 06/10/2021] [Indexed: 05/23/2023]
Abstract
Metal ions are essential for all forms of life. In prokaryotes, ATP-binding cassette (ABC) permeases serve as the primary import pathway for many micronutrients including the first-row transition metal manganese. However, the structural features of ionic metal transporting ABC permeases have remained undefined. Here, we present the crystal structure of the manganese transporter PsaBC from Streptococcus pneumoniae in an open-inward conformation. The type II transporter has a tightly closed transmembrane channel due to "extracellular gating" residues that prevent water permeation or ion reflux. Below these residues, the channel contains a hitherto unreported metal coordination site, which is essential for manganese translocation. Mutagenesis of the extracellular gate perturbs manganese uptake, while coordination site mutagenesis abolishes import. These structural features are highly conserved in metal-specific ABC transporters and are represented throughout the kingdoms of life. Collectively, our results define the structure of PsaBC and reveal the features required for divalent cation transport.
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Affiliation(s)
- Stephanie L Neville
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Jennie Sjöhamn
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Jacinta A Watts
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | | | - Stephen J Fairweather
- Research School of Chemistry, Australian National University, Canberra, ACT, Australia
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Katherine Ganio
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Alex Carey Hulyer
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Aaron P McGrath
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Andrew J Hayes
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Tess R Malcolm
- School of Chemistry and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Mark R Davies
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Norimichi Nomura
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - So Iwata
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- Research Acceleration Program, Membrane Protein Crystallography Project, Japan Science and Technology Agency, Kyoto, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, Japan
| | - Megan L O'Mara
- Research School of Chemistry, Australian National University, Canberra, ACT, Australia
| | - Megan J Maher
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia.
- School of Chemistry and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Christopher A McDevitt
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia.
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Masetti M, Bertazzo M, Recanatini M, Ciurli S, Musiani F. Probing the transport of Ni(II) ions through the internal tunnels of the Helicobacter pylori UreDFG multimeric protein complex. J Inorg Biochem 2021; 223:111554. [PMID: 34325209 DOI: 10.1016/j.jinorgbio.2021.111554] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/08/2021] [Accepted: 07/16/2021] [Indexed: 11/19/2022]
Abstract
The survival of several pathogenic bacteria, such as Helicobacter pylori (Hp), relies on the activity of the nickel-dependent enzyme urease. Nickel insertion into urease is mediated by a multimeric chaperone complex (HpUreDFG) that is responsible for the transport of Ni(II) from a conserved metal binding motif located in the UreG dimer (CPH motif) to the catalytic site of the enzyme. The X-ray structure of HpUreDFG revealed the presence of water-filled tunnels that were proposed as a route for Ni(II) translocation. Here, we probe the transport of Ni(II) through the internal tunnels of HpUreDFG, from the CPH motif to the external surface of the complex, using microsecond-long enhanced molecular dynamics simulations. The results suggest a "bucket-brigade" mechanism whereby Ni(II) can be transported through a series of stations found along these internal pathways.
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Affiliation(s)
- Matteo Masetti
- Laboratory of Computational Medicinal Chemistry, Department of Pharmacy and Biotechnology, Alma Mater Studiorum - University of Bologna, via Belmeloro 6, I-40126 Bologna, Italy.
| | - Martina Bertazzo
- Laboratory of Computational Medicinal Chemistry, Department of Pharmacy and Biotechnology, Alma Mater Studiorum - University of Bologna, via Belmeloro 6, I-40126 Bologna, Italy; Computational Sciences, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova, Italy
| | - Maurizio Recanatini
- Laboratory of Computational Medicinal Chemistry, Department of Pharmacy and Biotechnology, Alma Mater Studiorum - University of Bologna, via Belmeloro 6, I-40126 Bologna, Italy
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, Alma Mater Studiorum - University of Bologna, viale G. Fanin 40, I-40127 Bologna, Italy.
| | - Francesco Musiani
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, Alma Mater Studiorum - University of Bologna, viale G. Fanin 40, I-40127 Bologna, Italy.
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Woll KA, Van Petegem F. Calcium Release Channels: Structure and Function of IP3 Receptors and Ryanodine Receptors. Physiol Rev 2021; 102:209-268. [PMID: 34280054 DOI: 10.1152/physrev.00033.2020] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ca2+-release channels are giant membrane proteins that control the release of Ca2+ from the endoplasmic and sarcoplasmic reticulum. The two members, ryanodine receptors (RyRs) and inositol-1,4,5-trisphosphate Receptors (IP3Rs), are evolutionarily related and are both activated by cytosolic Ca2+. They share a common architecture, but RyRs have evolved additional modules in the cytosolic region. Their massive size allows for the regulation by tens of proteins and small molecules, which can affect the opening and closing of the channels. In addition to Ca2+, other major triggers include IP3 for the IP3Rs, and depolarization of the plasma membrane for a particular RyR subtype. Their size has made them popular targets for study via electron microscopic methods, with current structures culminating near 3Å. The available structures have provided many new mechanistic insights int the binding of auxiliary proteins and small molecules, how these can regulate channel opening, and the mechanisms of disease-associated mutations. They also help scrutinize previously proposed binding sites, as some of these are now incompatible with the structures. Many questions remain around the structural effects of post-translational modifications, additional binding partners, and the higher-order complexes these channels can make in situ. This review summarizes our current knowledge about the structures of Ca2+-release channels and how this informs on their function.
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Affiliation(s)
- Kellie A Woll
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
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35
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Yagi K, Ito S, Sugita Y. Exploring the Minimum-Energy Pathways and Free-Energy Profiles of Enzymatic Reactions with QM/MM Calculations. J Phys Chem B 2021; 125:4701-4713. [PMID: 33914537 PMCID: PMC10986901 DOI: 10.1021/acs.jpcb.1c01862] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Understanding molecular mechanisms of enzymatic reactions is of vital importance in biochemistry and biophysics. Here, we introduce new functions of hybrid quantum mechanical/molecular mechanical (QM/MM) calculations in the GENESIS program to compute the minimum-energy pathways (MEPs) and free-energy profiles of enzymatic reactions. For this purpose, an interface in GENESIS is developed to utilize a highly parallel electronic structure program, QSimulate-QM (https://qsimulate.com), calling it as a shared library from GENESIS. Second, algorithms to search the MEP are implemented, combining the string method (E et al. J. Chem. Phys. 2007, 126, 164103) with the energy minimization of the buffer MM region. The method implemented in GENESIS is applied to an enzyme, triosephosphate isomerase, which converts dihyroxyacetone phosphate to glyceraldehyde 3-phosphate in four proton-transfer processes. QM/MM-molecular dynamics simulations show performances of greater than 1 ns/day with the density functional tight binding (DFTB), and 10-30 ps/day with the hybrid density functional theory, B3LYP-D3. These performances allow us to compute not only MEP but also the potential of mean force (PMF) of the enzymatic reactions using the QM/MM calculations. The barrier height obtained as 13 kcal mol-1 with B3LYP-D3 in the QM/MM calculation is in agreement with the experimental results. The impact of conformational sampling in PMF calculations and the level of electronic structure calculations (DFTB vs B3LYP-D3) suggests reliable computational protocols for enzymatic reactions without high computational costs.
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Affiliation(s)
- Kiyoshi Yagi
- Theoretical
Molecular Science Laboratory, RIKEN Cluster
for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Shingo Ito
- Theoretical
Molecular Science Laboratory, RIKEN Cluster
for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yuji Sugita
- Theoretical
Molecular Science Laboratory, RIKEN Cluster
for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Computational
Biophysics Research Team, RIKEN Center for
Computational Science, 7-1-26 minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
- Laboratory
for Biomolecular Function Simulation, RIKEN
Center for Biosystems Dynamics Research, 1-6-5 minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
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36
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Liu C, Zhang A, Yan N, Song C. Atomistic Details of Charge/Space Competition in the Ca 2+ Selectivity of Ryanodine Receptors. J Phys Chem Lett 2021; 12:4286-4291. [PMID: 33909426 DOI: 10.1021/acs.jpclett.1c00681] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ryanodine receptors (RyRs) are ion channels responsible for the fast release of Ca2+ from the sarco/endoplasmic reticulum to the cytosol and show a selectivity of Ca2+ over monovalent cations. By utilizing a recently developed multisite Ca2+ model in molecular dynamic simulations, we show that multiple cations accumulate in the upper selectivity filter of RyRs, and the small size and high valence of Ca2+ make it preferable to K+ in competition for space in this confined region of negative electrostatic potential. The presence of Ca2+ in the upper selectivity filter significantly increases the energy barrier of K+ permeation, while the presence of K+ has little impact on the Ca2+ permeation. Our results provide the atomistic details of the charge/space competition mechanism for the ion selectivity of RyRs, which ensures the robustness of their Ca2+ release function. The mechanism could be utilized in protein- and nanoengineering for valence selectivity of ion species.
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Affiliation(s)
- Chunhong Liu
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Aihua Zhang
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Nieng Yan
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, United States
| | - Chen Song
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
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37
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Amin KS, Hu X, Salahub DR, Baldauf C, Lim C, Noskov S. Benchmarking polarizable and non-polarizable force fields for Ca2+–peptides against a comprehensive QM dataset. J Chem Phys 2020; 153:144102. [DOI: 10.1063/5.0020768] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Kazi S. Amin
- CMS – Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Xiaojuan Hu
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Dennis R. Salahub
- Department of Chemistry, CMS – Centre for Molecular Simulation, IQST – Institute for Quantum Science and Technology, Quantum Alberta, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Carsten Baldauf
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Carmay Lim
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Sergei Noskov
- CMS – Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
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