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Chan SSY, Lee D, Meivita MP, Li L, Tan YS, Bajalovic N, Loke DK. Ultrasensitive two-dimensional material-based MCF-7 cancer cell sensor driven by perturbation processes. NANOSCALE ADVANCES 2021; 3:6974-6983. [PMID: 36132361 PMCID: PMC9419592 DOI: 10.1039/d1na00614b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/13/2021] [Indexed: 06/15/2023]
Abstract
Changes in lipid composition and structure during cell development can be markers for cell apoptosis or various diseases such as cancer. Although traditional fluorescence techniques utilising molecular probes have been studied, these methods are limited in studying these micro-changes as they require complex probe preparation and cannot be reused, making cell monitoring and detection challenging. Here, we developed a direct current (DC) resistance sensor based on two-dimensional (2D) molybdenum disulfide (MoS2) nanosheets to enable cancer cell-specific detection dependent on micro-changes in the cancer cell membrane. Atomistic molecular dynamics (MD) simulations were used to study the interaction between 2D MoS2 and cancer lipid bilayer systems, and revealed that previously unconsidered perturbations in the lipid bilayer can cause an increase in resistance. Under an applied DC sweep, we observed an increase in resistance when cancer cells were incubated with the nanosheets. Furthermore, a correlation was observed between the resistance and breast cancer epithelial cell (MCF-7) population, illustrating a cell population-dependent sensitivity of our method. Our method has a detection limit of ∼3 × 103 cells, below a baseline of ∼1 × 104 cells for the current state-of-the-art electrical-based biosensors using an adherent monolayer with homogenous cells. This combination of a unique 2D material and electrical resistance framework represents a promising approach for the early detection of cancerous cells and to reduce the risk of post-surgery cancer recurrence.
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Affiliation(s)
- Sophia S Y Chan
- Department of Science, Mathematics and Technology, Singapore University of Technology and Design Singapore 487372 Singapore
| | - Denise Lee
- Department of Science, Mathematics and Technology, Singapore University of Technology and Design Singapore 487372 Singapore
| | - Maria Prisca Meivita
- Department of Science, Mathematics and Technology, Singapore University of Technology and Design Singapore 487372 Singapore
| | - Lunna Li
- Department of Science, Mathematics and Technology, Singapore University of Technology and Design Singapore 487372 Singapore
| | - Yaw Sing Tan
- Bioinformatics Institute, Agency for Science, Technology and Research (ASTAR) Singapore 138671 Singapore
| | - Natasa Bajalovic
- Department of Science, Mathematics and Technology, Singapore University of Technology and Design Singapore 487372 Singapore
| | - Desmond K Loke
- Department of Science, Mathematics and Technology, Singapore University of Technology and Design Singapore 487372 Singapore
- Office of Innovation, Changi General Hospital Singapore 529889 Singapore
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52
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Nele V, Holme MN, Rashid MH, Barriga HMG, Le TC, Thomas MR, Doutch JJ, Yarovsky I, Stevens MM. Design of Lipid-Based Nanocarriers via Cation Modulation of Ethanol-Interdigitated Lipid Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:11909-11921. [PMID: 34581180 DOI: 10.1021/acs.langmuir.1c02076] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Short-chain alcohols (i.e., ethanol) can induce membrane interdigitation in saturated-chain phosphatidylcholines (PCs). In this process, alcohol molecules intercalate between phosphate heads, increasing lateral separation and favoring hydrophobic interactions between opposing acyl chains, which interpenetrate forming an interdigitated phase. Unraveling mechanisms underlying the interactions between ethanol and model lipid membranes has implications for cell biology, biochemistry, and for the formulation of lipid-based nanocarriers. However, investigations of ethanol-lipid membrane systems have been carried out in deionized water, which limits their applicability. Here, using a combination of small- and wide-angle X-ray scattering, small-angle neutron scattering, and all-atom molecular dynamics simulations, we analyzed the effect of varying CaCl2 and NaCl concentrations on ethanol-induced interdigitation. We observed that while ethanol addition leads to the interdigitation of bulk phase 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers in the presence of CaCl2 and NaCl regardless of the salt concentration, the ethanol-induced interdigitation of vesicular DPPC depends on the choice of cation and its concentration. These findings unravel a key role for cations in the ethanol-induced interdigitation of lipid membranes in either bulk phase or vesicular form.
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Affiliation(s)
- Valeria Nele
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, U.K
| | - Margaret N Holme
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, U.K
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - M Harunur Rashid
- School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
- Department of Mathematics and Physics, North South University, Bashundhara, Dhaka 1229, Bangladesh
| | - Hanna M G Barriga
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Tu C Le
- School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Michael R Thomas
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, U.K
- London Centre for Nanotechnology and Department of Biochemical Engineering, University College London, 17-19 Gordon Street, London WC1H 0AH, U.K
| | - James J Doutch
- ISIS Neutron and Muon Source, STFC, Rutherford Appleton Laboratory, Didcot OX11 ODE, U.K
| | - Irene Yarovsky
- School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Molly M Stevens
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, U.K
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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53
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Velic A, Jaggessar A, Tesfamichael T, Li Z, Yarlagadda PKDV. Effects of Nanopillar Size and Spacing on Mechanical Perturbation and Bactericidal Killing Efficiency. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:2472. [PMID: 34684913 PMCID: PMC8540829 DOI: 10.3390/nano11102472] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 09/18/2021] [Indexed: 12/30/2022]
Abstract
Nanopatterned surfaces administer antibacterial activity through contact-induced mechanical stresses and strains, which can be modulated by changing the nanopattern's radius, spacing and height. However, due to conflicting recommendations throughout the theoretical literature with poor agreement to reported experimental trends, it remains unclear whether these key dimensions-particularly radius and spacing-should be increased or decreased to maximize bactericidal efficiency. It is shown here that a potential failure of biophysical models lies in neglecting any out-of-plane effects of nanopattern contact. To highlight this, stresses induced by a nanopattern were studied via an analytical model based on minimization of strain and adhesion energy. The in-plane (areal) and out-of-plane (contact pressure) stresses at equilibrium were derived, as well as a combined stress (von Mises), which comprises both. Contour plots were produced to illustrate which nanopatterns elicited the highest stresses over all combinations of tip radius between 0 and 100 nm and center spacing between 0 and 200 nm. Considering both the in-plane and out-of-plane stresses drastically transformed the contour plots from those when only in-plane stress was evaluated, clearly favoring small tipped, tightly packed nanopatterns. In addition, the effect of changes to radius and spacing in terms of the combined stress showed the best qualitative agreement with previous reported trends in killing efficiency. Together, the results affirm that the killing efficiency of a nanopattern can be maximized by simultaneous reduction in tip radius and increase in nanopattern packing ratio (i.e., radius/spacing). These findings provide a guide for the design of highly bactericidal nanopatterned surfaces.
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Affiliation(s)
| | | | | | | | - Prasad K. D. V. Yarlagadda
- School of Mechanical, Medical and Process Engineering, Engineering Faculty, and Centre for Biomedical Technologies, Queensland University of Technology, 2 George St, Brisbane, QLD 4000, Australia; (A.V.); (A.J.); (T.T.); (Z.L.)
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54
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Sikdar S, Banerjee M, Vemparala S. Effect of cholesterol on the membrane partitioning dynamics of hepatitis A virus-2B peptide. SOFT MATTER 2021; 17:7963-7977. [PMID: 34378608 DOI: 10.1039/d1sm01019k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Understanding viral peptide detection and partitioning and the subsequent host membrane composition-based response is essential for gaining insights into the viral mechanism. Here, we probe the crucial role of the presence of membrane lipid packing defects, depending on the membrane composition, in allowing the viral peptide belonging to C-terminal Hepatitis A Virus-2B (HAV-2B) to detect, attach and subsequently partition into host cell membrane mimics. Using molecular dynamics simulations, we conclusively show that the hydrophobic residues in the viral peptide detect transiently present lipid packing defects, insert themselves into such defects, form anchor points and facilitate the partitioning of the peptide, thereby inducing membrane disruption. We also show that the presence of cholesterol significantly alters such lipid packing defects, both in size and in number, thus mitigating the partitioning of the membrane active viral peptide into cholesterol-rich membranes. Our results are in excellent agreement with previously published experimental data and further explain the role of lipid defects in understanding such data. These results show differential ways in which the presence and absence of cholesterol can alter the permeability of the host membranes to the membrane active peptide component of HAV-2B virus, via lipid packing defects, and can possibly be a part of the general membrane detection mechanism for viroporins.
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Affiliation(s)
- Samapan Sikdar
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India.
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55
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Weigle AT, Carr M, Shukla D. Impact of Increased Membrane Realism on Conformational Sampling of Proteins. J Chem Theory Comput 2021; 17:5342-5357. [PMID: 34339605 DOI: 10.1021/acs.jctc.1c00276] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The realism and accuracy of lipid bilayer simulations through molecular dynamics (MD) are heavily dependent on the lipid composition. While the field is pushing toward implementing more heterogeneous and realistic membrane compositions, a lack of high-resolution lipidomic data prevents some membrane protein systems from being modeled with the highest level of realism. Given the additional diversity of real-world cellular membranes and protein-lipid interactions, it is still not fully understood how altering membrane complexity affects modeled membrane protein functions or if it matters over long-timescale simulations. This is especially true for organisms whose membrane environments have little to no computational study, such as the plant plasma membrane. Tackling these issues in tandem, a generalized, realistic, and asymmetric plant plasma membrane with more than 10 different lipid species is constructed herein. Classical MD simulations of pure membrane constructs were performed to evaluate how altering the compositional complexity of the membrane impacted the plant membrane properties. The apo form of a plant sugar transporter, OsSWEET2b, was inserted into membrane models where lipid diversity was calculated in either a size-dependent or size-independent manner. An adaptive sampling simulation regime validated by Markov-state models was performed to capture the gating dynamics of OsSWEET2b in each of these membrane constructs. In comparison to previous OsSWEET2b simulations performed in a pure POPC bilayer, we confirm that simulations performed within a native-like membrane composition alter the stabilization of apo OsSWEET2b conformational states by ∼1 kcal/mol. The free-energy barriers of intermediate conformational states decrease when realistic membrane complexity is simplified, albeit roughly within sampling error, suggesting that protein-specific responses to membranes differ due to altered packing caused by compositional fluctuations. This work serves as a case study where a more realistic bilayer composition makes unbiased conformational sampling easier to achieve than with simplified bilayers.
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Affiliation(s)
- Austin T Weigle
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Matthew Carr
- Independent Software Development Provider310 East Marlette Avenue, Phoenix, Arizona 85012, United States
| | - Diwakar Shukla
- Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Center for Digital Agriculture, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,NIH Center for Macromolecular Modeling and Bioinformatics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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56
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Scott HL, Kennison KB, Enoki TA, Doktorova M, Kinnun JJ, Heberle FA, Katsaras J. Model Membrane Systems Used to Study Plasma Membrane Lipid Asymmetry. Symmetry (Basel) 2021; 13. [PMID: 35498375 PMCID: PMC9053528 DOI: 10.3390/sym13081356] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
It is well known that the lipid distribution in the bilayer leaflets of mammalian plasma membranes (PMs) is not symmetric. Despite this, model membrane studies have largely relied on chemically symmetric model membranes for the study of lipid–lipid and lipid–protein interactions. This is primarily due to the difficulty in preparing stable, asymmetric model membranes that are amenable to biophysical studies. However, in the last 20 years, efforts have been made in producing more biologically faithful model membranes. Here, we review several recently developed experimental and computational techniques for the robust generation of asymmetric model membranes and highlight a new and particularly promising technique to study membrane asymmetry.
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Affiliation(s)
- Haden L. Scott
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - Kristen B. Kennison
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - Thais A. Enoki
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - Milka Doktorova
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - Jacob J. Kinnun
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - Frederick A. Heberle
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - John Katsaras
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Sample Environment Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
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57
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Teo RD, Tieleman DP. Modulation of Phospholipid Bilayer Properties by Simvastatin. J Phys Chem B 2021; 125:8406-8418. [PMID: 34296883 DOI: 10.1021/acs.jpcb.1c03359] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Simvastatin (Zocor) is one of the most prescribed drugs for reducing high cholesterol. Although simvastatin is ingested in its inactive lactone form, it is converted to its active dihydroxyheptanoate form by carboxylesterases in the liver. The dihydroxyheptanoate form can also be converted back to its original lactone form. Unfortunately, some of the side effects associated with the intake of simvastatin and other lipophilic statins at higher doses include statin-associated myopathy (SAM) and, in more severe cases, kidney failure. While the cause of SAM is unknown, it is hypothesized that these side effects are dependent on the localization of statins in lipid bilayers and their impact on bilayer properties. In this work, we carry out all-atom molecular dynamics simulations on both the lactone and dihydroxyheptanoate forms of simvastatin (termed "SN" and "SA", respectively) with a pure 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid bilayer and a POPC/cholesterol (30 mol %) binary mixture as membrane models. Additional simulations were carried out with multiple simvastatin molecules to mimic in vitro conditions that produced pleiotropic effects. Both SN and SA spontaneously diffused into the lipid bilayer, and a longer simulation time of 4 μs was needed for the complete incorporation of multiple SAs into the bilayer. By constructing potential mean force and electron density profiles, we find that SN localizes deeper within the hydrophobic interior of the bilayer and that SA has a greater tendency to form hydrogen-bonding interactions with neighboring water molecules and lipid headgroups. For the pure POPC bilayer, both SN and SA increase membrane order, while membrane fluidity increases for the POPC/cholesterol bilayer.
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Affiliation(s)
- Ruijie D Teo
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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58
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Kothari S, Bala N, Patel AB, Donovan A, Narayanaswami V. The LDL receptor binding domain of apolipoprotein E directs the relative orientation of its C-terminal segment in reconstituted nascent HDL. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183618. [PMID: 33831404 PMCID: PMC8211829 DOI: 10.1016/j.bbamem.2021.183618] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 03/11/2021] [Accepted: 03/22/2021] [Indexed: 12/24/2022]
Abstract
Apolipoprotein E (apoE) (299 residues) is a highly helical protein that plays a critical role in cholesterol homeostasis. It comprises a four-helix bundle N-terminal (NT) and a C-terminal (CT) domain that can exist in lipid-free and lipid-associated states. In humans, there are two major apoE isoforms, apoE3 and apoE4, which differ in a single residue in the NT domain, with apoE4 strongly increasing risk of Alzheimer's disease (AD) and cardiovascular diseases (CVD). It has been proposed that the CT domain initiates rapid lipid binding, followed by a slower NT domain helix bundle opening and lipid binding to yield discoidal reconstituted high density lipoprotein (rHDL). However, the contribution of the NT domain on the CT domain organization in HDL remains poorly understood. To understand this, we employed Cys-specific cross-linking and spatially-sensitive fluorophores in the NT and CT domains of apoE3 and apoE4, and in isolated CT domain. We noted that the helices in isolated CT domain are oriented parallel to those in the neighboring molecule in rHDL, whereas full length apoE3 and apoE4 adopt either an anti-parallel or hairpin-like organization. It appears that the bulky NT domain determines the spatial organization of its CT domain in rHDL, a finding that has significance for apoE4, which is more susceptible to proteolytic cleavage in AD brains, showing increased accumulation of neurotoxic NT and CT fragments. We envisage that the structural organization of HDL apoE would have profound functional consequences in its ability to regulate cholesterol homeostasis in AD and CVD.
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Affiliation(s)
- S Kothari
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - N Bala
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - A B Patel
- Department of Neuroscience, Novartis Institutes for BioMedical Research, Cambridge, MA 02139, USA
| | - A Donovan
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90033, USA
| | - V Narayanaswami
- Department of Chemistry and Biochemistry, 1250 Bellflower Blvd., California State University, Long Beach, Long Beach, CA 90840, USA.
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59
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Interaction between the transmembrane domains of neurotrophin receptors p75 and TrkA mediates their reciprocal activation. J Biol Chem 2021; 297:100926. [PMID: 34216618 PMCID: PMC8327350 DOI: 10.1016/j.jbc.2021.100926] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/25/2021] [Accepted: 06/28/2021] [Indexed: 11/23/2022] Open
Abstract
The neurotrophin receptors p75 and tyrosine protein kinase receptor A (TrkA) play important roles in the development and survival of the nervous system. Biochemical data suggest that p75 and TrkA reciprocally regulate the activities of each other. For instance, p75 is able to regulate the response of TrkA to lower concentrations of nerve growth factor (NGF), and TrkA promotes shedding of the extracellular domain of p75 by α-secretases in a ligand-dependent manner. The current model suggests that p75 and TrkA are regulated by means of a direct physical interaction; however, the nature of such interaction has been elusive thus far. Here, using NMR in micelles, multiscale molecular dynamics, FRET, and functional studies, we identified and characterized the direct interaction between TrkA and p75 through their respective transmembrane domains (TMDs). Molecular dynamics of p75-TMD mutants suggests that although the interaction between TrkA and p75 TMDs is maintained upon mutation, a specific protein interface is required to facilitate TrkA active homodimerization in the presence of NGF. The same mutations in the TMD protein interface of p75 reduced the activation of TrkA by NGF as well as reducing cell differentiation. In summary, we provide a structural model of the p75–TrkA receptor complex necessary for neuronal development stabilized by TMD interactions.
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60
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Phyo P, Zhao X, Templeton AC, Xu W, Cheung JK, Su Y. Understanding molecular mechanisms of biologics drug delivery and stability from NMR spectroscopy. Adv Drug Deliv Rev 2021; 174:1-29. [PMID: 33609600 DOI: 10.1016/j.addr.2021.02.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/20/2021] [Accepted: 02/07/2021] [Indexed: 02/06/2023]
Abstract
Protein therapeutics carry inherent limitations of membrane impermeability and structural instability, despite their predominant role in the modern pharmaceutical market. Effective formulations are needed to overcome physiological and physicochemical barriers, respectively, for improving bioavailability and stability. Knowledge of membrane affinity, cellular internalization, encapsulation, and release of drug-loaded carrier vehicles uncover the structural basis for designing and optimizing biopharmaceuticals with enhanced delivery efficiency and therapeutic efficacy. Understanding stabilizing and destabilizing interactions between protein drugs and formulation excipients provide fundamental mechanisms for ensuring the stability and quality of biological products. This article reviews the molecular studies of biologics using solution and solid-state NMR spectroscopy on structural attributes pivotal to drug delivery and stability. In-depth investigation of the structure-function relationship of drug delivery systems based on cell-penetrating peptides, lipid nanoparticles and polymeric colloidal, and biophysical and biochemical stability of peptide, protein, monoclonal antibody, and vaccine, as the integrative efforts on drug product design, will be elaborated.
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Affiliation(s)
- Pyae Phyo
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Xi Zhao
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Allen C Templeton
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Wei Xu
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Jason K Cheung
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Yongchao Su
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States.
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61
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Kadir SR, Lilja A, Gunn N, Strong C, Hughes RT, Bailey BJ, Rae J, Parton RG, McGhee J. Nanoscape, a data-driven 3D real-time interactive virtual cell environment. eLife 2021; 10:64047. [PMID: 34191720 PMCID: PMC8245131 DOI: 10.7554/elife.64047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 06/04/2021] [Indexed: 12/15/2022] Open
Abstract
Our understanding of cellular and structural biology has reached unprecedented levels of detail, and computer visualisation techniques can be used to create three-dimensional (3D) representations of cells and their environment that are useful in both teaching and research. However, extracting and integrating the relevant scientific data, and then presenting them in an effective way, can pose substantial computational and aesthetic challenges. Here we report how computer artists, experts in computer graphics and cell biologists have collaborated to produce a tool called Nanoscape that allows users to explore and interact with 3D representations of cells and their environment that are both scientifically accurate and visually appealing. We believe that using Nanoscape as an immersive learning application will lead to an improved understanding of the complexities of cellular scales, densities and interactions compared with traditional learning modalities.
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Affiliation(s)
- Shereen R Kadir
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Andrew Lilja
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Nick Gunn
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Campbell Strong
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Rowan T Hughes
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Benjamin J Bailey
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - James Rae
- Institute for Molecular Bioscience, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Australia
| | - John McGhee
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
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Chakraborty R, Dey S, Sil P, Paul SS, Bhattacharyya D, Bhunia A, Sengupta J, Chattopadhyay K. Conformational distortion in a fibril-forming oligomer arrests alpha-Synuclein fibrillation and minimizes its toxic effects. Commun Biol 2021; 4:518. [PMID: 33941845 PMCID: PMC8093279 DOI: 10.1038/s42003-021-02026-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 03/25/2021] [Indexed: 02/06/2023] Open
Abstract
The fibrillation pathway of alpha-Synuclein, the causative protein of Parkinson's disease, encompasses transient, heterogeneous oligomeric forms whose structural understanding and link to toxicity are not yet understood. We report that the addition of the physiologically-available small molecule heme at a sub-stoichiometric ratio to either monomeric or aggregated α-Syn, targets a His50 residue critical for fibril-formation and stabilizes the structurally-heterogeneous populations of aggregates into a minimally-toxic oligomeric state. Cryo-EM 3D reconstruction revealed a 'mace'-shaped structure of this monodisperse population of oligomers, which is comparable to a solid-state NMR Greek key-like motif (where the core residues are arranged in parallel in-register sheets with a Greek key topology at the C terminus) that forms the fundamental unit/kernel of protofilaments. Further structural analyses suggest that heme binding induces a distortion in the Greek key-like architecture of the mace oligomers, which impairs their further appending into protofilaments and fibrils. Additionally, our study reports a novel mechanism of prevention as well as reclamation of amyloid fibril formation by blocking an inter-protofilament His50 residue using a small molecule.
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Affiliation(s)
- Ritobrita Chakraborty
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Sandip Dey
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Pallabi Sil
- Department of Physics, University of Alberta, Edmonton, AB, Canada
| | - Simanta Sarani Paul
- Department of Medicine, Centre for Prion and Protein folding disease, University of Alberta, Edmonton, AB, Canada
| | - Dipita Bhattacharyya
- Department of Biophysics, Bose Institute- Centenary Campus, P-1/12C.I.T. Scheme VII-M, Kolkata, India
| | - Anirban Bhunia
- Department of Biophysics, Bose Institute- Centenary Campus, P-1/12C.I.T. Scheme VII-M, Kolkata, India
| | - Jayati Sengupta
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India.
| | - Krishnananda Chattopadhyay
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India.
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63
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Water Pores in Planar Lipid Bilayers at Fast and Slow Rise of Transmembrane Voltage. MEMBRANES 2021; 11:membranes11040263. [PMID: 33916447 PMCID: PMC8067013 DOI: 10.3390/membranes11040263] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 03/28/2021] [Accepted: 03/29/2021] [Indexed: 12/12/2022]
Abstract
Basic understanding of the barrier properties of biological membranes can be obtained by studying model systems, such as planar lipid bilayers. Here, we study water pores in planar lipid bilayers in the presence of transmembrane voltage. Planar lipid bilayers were exposed to fast and slow linearly increasing voltage and current signals. We measured the capacitance, breakdown voltage, and rupture time of planar lipid bilayers composed of 1-pamitoyl 2-oleoyl phosphatidylcholine (POPC), 1-pamitoyl 2-oleoyl phosphatidylserine (POPS), and a mixture of both lipids in a 1:1 ratio. Based on the measurements, we evaluated the change in the capacitance of the planar lipid bilayer corresponding to water pores, the radius of water pores at membrane rupture, and the fraction of the area of the planar lipid bilayer occupied by water pores.planar lipid bilayer capacitance, which corresponds to water pores, water pore radius at the membrane rupture, and a fraction of the planar lipid bilayer area occupied by water pores. The estimated pore radii determining the rupture of the planar lipid bilayer upon fast build-up of transmembrane voltage are 0.101 nm, 0.110 nm, and 0.106 nm for membranes composed of POPC, POPS, and POPC:POPS, respectively. The fraction of the surface occupied by water pores at the moment of rupture of the planar lipid bilayer The fraction of an area that is occupied by water pores at the moment of planar lipid bilayer rupture is in the range of 0.1–1.8%.
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64
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Murakami K, Sato M, Miyasaka Y, Hatori K. Selective association of desmin intermediate filaments with a phospholipid layer in droplets. Biochem Biophys Res Commun 2021; 555:109-114. [PMID: 33813269 DOI: 10.1016/j.bbrc.2021.03.131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 03/24/2021] [Indexed: 10/24/2022]
Abstract
Desmin, an intermediate filament protein expressed in muscle cells, plays a key role in the integrity and regulation of the contractile system. Furthermore, the distribution of desmin in cells and its interplay with plasma and organelle membranes are crucial for cell functions; however, the fundamental properties of lipid-desmin interactions remain unknown. Using a water-in-oil method for a limited space system in vitro, we examined the distribution of desmin in three types of phospholipid droplets: 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), and 1,2-dioleoyl-sn-glycero-3-phosphoserine (DOPS). When fluorescent-labeled desmin was observed for 60 min after desmin assembly was initiated by adding 25 mM KCl, desmin accumulated on both the DOPE and DOPS layers; however, it did not accumulate on the DOPC layer of droplets. An increase in salt concentration did not moderate the accumulation. The initial form of either oligomer or mature filament affected the accumulation on each lipid layer. When liposomes were included in the droplets, desmin was associated with DOPE but not on DOPC liposomes. These results suggest that desmin has the potential for association with phospholipids concerning desmin form and lipid shape. The behavior and composition of living membranes may affect the distribution of desmin networks.
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Affiliation(s)
- Keigo Murakami
- Department of Bio-Systems Engineering, Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jyonan, Yonezawa, 992-8510, Japan
| | - Masashi Sato
- Department of Bio-Systems Engineering, Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jyonan, Yonezawa, 992-8510, Japan
| | - Yoshiya Miyasaka
- Department of Bio-Systems Engineering, Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jyonan, Yonezawa, 992-8510, Japan
| | - Kuniyuki Hatori
- Department of Bio-Systems Engineering, Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jyonan, Yonezawa, 992-8510, Japan.
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65
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Casalini T. Not only in silico drug discovery: Molecular modeling towards in silico drug delivery formulations. J Control Release 2021; 332:390-417. [PMID: 33675875 DOI: 10.1016/j.jconrel.2021.03.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 02/28/2021] [Accepted: 03/02/2021] [Indexed: 12/18/2022]
Abstract
The use of methods at molecular scale for the discovery of new potential active ligands, as well as previously unknown binding sites for target proteins, is now an established reality. Literature offers many successful stories of active compounds developed starting from insights obtained in silico and approved by Food and Drug Administration (FDA). One of the most famous examples is raltegravir, a HIV integrase inhibitor, which was developed after the discovery of a previously unknown transient binding area thanks to molecular dynamics simulations. Molecular simulations have the potential to also improve the design and engineering of drug delivery devices, which are still largely based on fundamental conservation equations. Although they can highlight the dominant release mechanism and quantitatively link the release rate to design parameters (size, drug loading, et cetera), their spatial resolution does not allow to fully capture how phenomena at molecular scale influence system behavior. In this scenario, the "computational microscope" offered by simulations at atomic scale can shed light on the impact of molecular interactions on crucial parameters such as release rate and the response of the drug delivery device to external stimuli, providing insights that are difficult or impossible to obtain experimentally. Moreover, the new paradigm brought by nanomedicine further underlined the importance of such computational microscope to study the interactions between nanoparticles and biological components with an unprecedented level of detail. Such knowledge is a fundamental pillar to perform device engineering and to achieve efficient and safe formulations. After a brief theoretical background, this review aims at discussing the potential of molecular simulations for the rational design of drug delivery systems.
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Affiliation(s)
- Tommaso Casalini
- Department of Chemistry and Applied Bioscience, Institute for Chemical and Bioengineering, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, Zürich 8093, Switzerland; Polymer Engineering Laboratory, Institute for Mechanical Engineering and Materials Technology, University of Applied Sciences and Arts of Southern Switzerland (SUPSI), Via la Santa 1, Lugano 6962, Switzerland.
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66
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Khelashvili G, Plante A, Doktorova M, Weinstein H. Ca 2+-dependent mechanism of membrane insertion and destabilization by the SARS-CoV-2 fusion peptide. Biophys J 2021; 120:1105-1119. [PMID: 33631204 PMCID: PMC7899928 DOI: 10.1016/j.bpj.2021.02.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/10/2021] [Accepted: 02/02/2021] [Indexed: 01/05/2023] Open
Abstract
Cell penetration after recognition of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus by the ACE2 receptor and the fusion of its viral envelope membrane with cellular membranes are the early steps of infectivity. A region of the Spike protein of the virus, identified as the "fusion peptide" (FP), is liberated at its N-terminal site by a specific cleavage occurring in concert with the interaction of the receptor-binding domain of the Spike. Studies have shown that penetration is enhanced by the required binding of Ca2+ ions to the FPs of coronaviruses, but the mechanisms of membrane insertion and destabilization remain unclear. We have predicted the preferred positions of Ca2+ binding to the SARS-CoV-2-FP, the role of Ca2+ ions in mediating peptide-membrane interactions, the preferred mode of insertion of the Ca2+-bound SARS-CoV-2-FP, and consequent effects on the lipid bilayer from extensive atomistic molecular dynamics simulations and trajectory analyses. In a systematic sampling of the interactions of the Ca2+-bound peptide models with lipid membranes, SARS-CoV-2-FP penetrated the bilayer and disrupted its organization only in two modes involving different structural domains. In one, the hydrophobic residues F833/I834 from the middle region of the peptide are inserted. In the other, more prevalent mode, the penetration involves residues L822/F823 from the LLF motif, which is conserved in CoV-2-like viruses, and is achieved by the binding of Ca2+ ions to the D830/D839 and E819/D820 residue pairs. FP penetration is shown to modify the molecular organization in specific areas of the bilayer, and the extent of membrane binding of the SARS-CoV-2 FP is significantly reduced in the absence of Ca2+ ions. These findings provide novel mechanistic insights regarding the role of Ca2+ in mediating SARS-CoV-2 fusion and provide a detailed structural platform to aid the ongoing efforts in rational design of compounds to inhibit SARS-CoV-2 cell entry.
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Affiliation(s)
- George Khelashvili
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, New York; Institute for Computational Biomedicine, Weill Cornell Medical College of Cornell University, New York, New York.
| | - Ambrose Plante
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, New York
| | - Milka Doktorova
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Harel Weinstein
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, New York; Institute for Computational Biomedicine, Weill Cornell Medical College of Cornell University, New York, New York.
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67
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Study of Resveratrol's Interaction with Planar Lipid Models: Insights into Its Location in Lipid Bilayers. MEMBRANES 2021; 11:membranes11020132. [PMID: 33672841 PMCID: PMC7918209 DOI: 10.3390/membranes11020132] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 01/16/2023]
Abstract
Resveratrol, a polyphenolic molecule found in edible fruits and vegetables, shows a wide range of beneficial effects on human health, including anti-microbial, anti-inflammatory, anti-cancer, and anti-aging properties. Due to its poor water solubility and high liposome-water partition coefficient, the biomembrane seems to be the main target of resveratrol, although the mode of interaction with membrane lipids and its location within the cell membrane are still unclear. In this study, using electrophysiological measurements, we study the interaction of resveratrol with planar lipid membranes (PLMs) of different composition. We found that resveratrol incorporates into palmitoyl-oleoyl-phosphatidylcholine (POPC) and POPC:Ch PLMs and forms conductive units unlike those found in dioleoyl-phosphatidylserine (DOPS):dioleoyl-phosphatidylethanolamine (DOPE) PLMs. The variation of the biophysical parameters of PLMs in the presence of resveratrol provides information on its location within a lipid double layer, thus contributing to an understanding of its mechanism of action.
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68
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Gul G, Ileri-Ercan N. Fullerene translocation through peroxidized lipid membranes. RSC Adv 2021; 11:7575-7586. [PMID: 35423238 PMCID: PMC8694942 DOI: 10.1039/d1ra00272d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 02/08/2021] [Indexed: 12/20/2022] Open
Abstract
Recent cytotoxicity research suggests that fullerenes can enter the cell and cross the blood-brain barrier. However, the underlying toxicity mechanism behind the penetration of fullerenes through biological membranes is still not well understood. Here we perform coarse-grained molecular dynamics simulations to investigate the interactions of fullerenes and their polar derivatives (Janus) with model regular and peroxidized bilayers. We show that the translocation of fullerenes and their residence time in bulk water vary depending on the bilayer's peroxidation degree and fullerene polarity. The distribution of fullerenes inside the bilayer is mainly determined by the peroxidation degree and the saturation level of lipid acyl chains. The transport of pristine fullerenes through bilayers occurs at nano timescale while the complete diffusion may not be achieved for Janus fullerenes in micro timescale. As for the toxic response of fullerenes in terms of membrane damage, no mechanical disruption of model bilayers is observed throughout the studied simulation times.
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Affiliation(s)
- Gulsah Gul
- Department of Chemical Engineering, Bogazici University Istanbul Turkey
| | - Nazar Ileri-Ercan
- Department of Chemical Engineering, Bogazici University Istanbul Turkey
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69
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Schmidt TF, Riske KA, Caseli L, Salesse C. Dengue fusion peptide in Langmuir monolayers: A binding parameter study. Biophys Chem 2021; 271:106553. [PMID: 33626461 DOI: 10.1016/j.bpc.2021.106553] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/08/2021] [Accepted: 01/27/2021] [Indexed: 10/22/2022]
Abstract
Membrane fusion is known to be the primary mechanism of entry of flaviviruses into host cells. Several studies reported the investigation of the membrane fusion mechanism mediated by the fusion peptide, a component of the membrane protein surrounding the flaviviruses. In this study, we investigated the interaction of Dengue fusion peptide (FLAg) with Langmuir monolayers to uncover the role of membrane charges and organization in its membrane binding. Binding parameters of FLAg were obtained by measuring its adsorption onto Langmuir monolayers of different types of individual lipids, as well as their mixtures. Specific peptide binding was observed in the presence of charged lipid monolayers at different pHs, revealing that the lipid composition of the membrane modulates peptide interaction, and the preference of the peptide for negatively charged lipids.
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Affiliation(s)
- Thaís F Schmidt
- Universidade Federal de São Paulo, Biophysics Department, São Paulo, SP, Brazil; Universidade Federal de São Paulo, Chemistry Department, Diadema, SP, Brazil; CUO-Recherche, Centre de recherche du CHU de Québec-Université Laval and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada.
| | - Karin A Riske
- Universidade Federal de São Paulo, Biophysics Department, São Paulo, SP, Brazil
| | - Luciano Caseli
- Universidade Federal de São Paulo, Chemistry Department, Diadema, SP, Brazil
| | - Christian Salesse
- CUO-Recherche, Centre de recherche du CHU de Québec-Université Laval and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada
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70
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Khelashvili G, Plante A, Doktorova M, Weinstein H. Ca 2+ -dependent mechanism of membrane insertion and destabilization by the SARS-CoV-2 fusion peptide. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021. [PMID: 33299996 DOI: 10.1101/2020.12.03.410472] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Cell penetration after recognition of the SARS-CoV-2 virus by the ACE2 receptor, and the fusion of its viral envelope membrane with cellular membranes, are the early steps of infectivity. A region of the Spike protein (S) of the virus, identified as the "fusion peptide" (FP), is liberated at its N-terminal site by a specific cleavage occurring in concert with the interaction of the receptor binding domain of the Spike. Studies have shown that penetration is enhanced by the required binding of Ca 2+ ions to the FPs of corona viruses, but the mechanisms of membrane insertion and destabilization remain unclear. We have predicted the preferred positions of Ca 2+ binding to the SARS-CoV-2-FP, the role of Ca 2+ ions in mediating peptide-membrane interactions, the preferred mode of insertion of the Ca 2+ -bound SARS-CoV-2-FP and consequent effects on the lipid bilayer from extensive atomistic molecular dynamics (MD) simulations and trajectory analyses. In a systematic sampling of the interactions of the Ca 2+ -bound peptide models with lipid membranes SARS-CoV-2-FP penetrated the bilayer and disrupted its organization only in two modes involving different structural domains. In one, the hydrophobic residues F833/I834 from the middle region of the peptide are inserted. In the other, more prevalent mode, the penetration involves residues L822/F823 from the LLF motif which is conserved in CoV-2-like viruses, and is achieved by the binding of Ca 2+ ions to the D830/D839 and E819/D820 residue pairs. FP penetration is shown to modify the molecular organization in specific areas of the bilayer, and the extent of membrane binding of the SARS-CoV-2 FP is significantly reduced in the absence of Ca 2+ ions. These findings provide novel mechanistic insights regarding the role of Ca 2+ in mediating SARS-CoV-2 fusion and provide a detailed structural platform to aid the ongoing efforts in rational design of compounds to inhibit SARS-CoV-2 cell entry. STATEMENT OF SIGNIFICANCE SARS-CoV-2, the cause of the COVID-19 pandemic, penetrates host cell membranes and uses viral-to-cellular membrane fusion to release its genetic material for replication. Experiments had identified a region termed "fusion peptide" (FP) in the Spike proteins of coronaviruses, as the spearhead in these initial processes, and suggested that Ca 2+ is needed to support both functions. Absent structure and dynamics-based mechanistic information these FP functions could not be targeted for therapeutic interventions. We describe the development and determination of the missing information from analysis of extensive MD simulation trajectories, and propose specific Ca 2+ -dependent mechanisms of SARS-CoV-2-FP membrane insertion and destabilization. These results offer a structure-specific platform to aid the ongoing efforts to use this target for the discovery and/or of inhibitors.
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71
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Yee SM, Gillams RJ, McLain SE, Lorenz CD. Effects of lipid heterogeneity on model human brain lipid membranes. SOFT MATTER 2021; 17:126-135. [PMID: 33155582 DOI: 10.1039/d0sm01766c] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Cell membranes naturally contain a heterogeneous lipid distribution. However, homogeneous bilayers are commonly preferred and utilised in computer simulations due to their relative simplicity, and the availability of lipid force field parameters. Recently, experimental lipidomics data for the human brain cell membranes under healthy and Alzheimer's disease (AD) conditions were investigated, since disruption to the lipid composition has been implicated in neurodegenerative disorders, including AD [R. B. Chan et al., J. Biol. Chem., 2012, 287, 2678-2688]. In order to observe the effects of lipid complexity on the various bilayer properties, molecular dynamics simulations were used to study four membranes with increasing heterogeneity: a pure POPC membrane, a POPC and cholesterol membrane in a 1 : 1 ratio (POPC-CHOL), and to our knowledge, the first realistic models of a healthy brain membrane and an Alzheimer's diseased brain membrane. Numerous structural, interfacial, and dynamical properties, including the area per lipid, interdigitation, dipole potential, and lateral diffusion of the two simple models, POPC and POPC-CHOL, were analysed and compared to those of the complex brain models consisting of 27 lipid components. As the membranes gain heterogeneity, a number of alterations were found in the structural and dynamical properties, and more significant differences were observed in the lateral diffusion. Additionally, we observed snorkeling behaviour of the lipid tails that may play a role in the permeation of small molecules across biological membranes. In this work, atomistic description of realistic brain membrane models is provided, which can add insight towards the permeability and transport pathways of small molecules across these membrane barriers.
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Affiliation(s)
- Sze May Yee
- Department of Physics, King's College London, London WC2R 2LS, UK.
| | - Richard J Gillams
- School of Electronics and Computer Science, and Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Sylvia E McLain
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9RH, UK
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72
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Velic A, Hasan J, Li Z, Yarlagadda PKDV. Mechanics of Bacterial Interaction and Death on Nanopatterned Surfaces. Biophys J 2020; 120:217-231. [PMID: 33333030 DOI: 10.1016/j.bpj.2020.12.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/20/2020] [Accepted: 12/01/2020] [Indexed: 02/07/2023] Open
Abstract
Nanopatterned surfaces are believed to kill bacteria through physical deformation, a mechanism that has immense potential against biochemical resistance. Because of its elusive nature, this mechanism is mostly understood through biophysical modeling. Problematically, accurate descriptions of the contact mechanics and various boundary conditions involved in the bacteria-nanopattern interaction remain to be seen. This may underpin conflicting predictions, found throughout the literature, regarding two important aspects of the mechanism-that is, its critical action site and relationship with geometry. Herein, a robust computational analysis of bacteria-nanopattern interaction is performed using a three-dimensional finite element modeling that incorporates relevant continuum mechanical properties, multilayered envelope structure, and adhesion interaction conditions. The model is applied to more accurately study the elusory mechanism and its enhancement via nanopattern geometry. Additionally, micrographs of bacteria adhered on a nanopatterned cicada wing are examined to further inform and verify the major modeling predictions. Together, the results indicate that nanopatterned surfaces do not kill bacteria predominantly by rupture in between protruding pillars as previously thought. Instead, nondevelopable deformation about pillar tips is more likely to create a critical site at the pillar apex, which delivers significant in-plane strains and may locally rupture and penetrate the cell. The computational analysis also demonstrates that envelope deformation is increased by adhesion to nanopatterns with smaller pillar radii and spacing. These results further progress understanding of the mechanism of nanopatterned surfaces and help guide their design for enhanced bactericidal efficiency.
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Affiliation(s)
- Amar Velic
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, Queensland, Australia; Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Jafar Hasan
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, Queensland, Australia; Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Zhiyong Li
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, Queensland, Australia; Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Prasad K D V Yarlagadda
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, Queensland, Australia; Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, Queensland, Australia.
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73
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Puentes PR, Henao MC, Torres CE, Gómez SC, Gómez LA, Burgos JC, Arbeláez P, Osma JF, Muñoz-Camargo C, Reyes LH, Cruz JC. Design, Screening, and Testing of Non-Rational Peptide Libraries with Antimicrobial Activity: In Silico and Experimental Approaches. Antibiotics (Basel) 2020; 9:E854. [PMID: 33265897 PMCID: PMC7759991 DOI: 10.3390/antibiotics9120854] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 11/20/2020] [Accepted: 11/23/2020] [Indexed: 12/13/2022] Open
Abstract
One of the challenges of modern biotechnology is to find new routes to mitigate the resistance to conventional antibiotics. Antimicrobial peptides (AMPs) are an alternative type of biomolecules, naturally present in a wide variety of organisms, with the capacity to overcome the current microorganism resistance threat. Here, we reviewed our recent efforts to develop a new library of non-rationally produced AMPs that relies on bacterial genome inherent diversity and compared it with rationally designed libraries. Our approach is based on a four-stage workflow process that incorporates the interplay of recent developments in four major emerging technologies: artificial intelligence, molecular dynamics, surface-display in microorganisms, and microfluidics. Implementing this framework is challenging because to obtain reliable results, the in silico algorithms to search for candidate AMPs need to overcome issues of the state-of-the-art approaches that limit the possibilities for multi-space data distribution analyses in extremely large databases. We expect to tackle this challenge by using a recently developed classification algorithm based on deep learning models that rely on convolutional layers and gated recurrent units. This will be complemented by carefully tailored molecular dynamics simulations to elucidate specific interactions with lipid bilayers. Candidate AMPs will be recombinantly-expressed on the surface of microorganisms for further screening via different droplet-based microfluidic-based strategies to identify AMPs with the desired lytic abilities. We believe that the proposed approach opens opportunities for searching and screening bioactive peptides for other applications.
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Affiliation(s)
- Paola Ruiz Puentes
- Center for Research and Formation in Artificial Intelligence, Universidad de los Andes, Bogota DC 111711, Colombia; (P.R.P.); (P.A.)
- Department of Biomedical Engineering, Universidad de los Andes, Bogota DC 111711, Colombia; (C.E.T.); (S.C.G.); (L.A.G.); (C.M.-C.)
| | - María C. Henao
- Grupo de Diseño de Productos y Procesos, Department of Chemical and Food Engineering, Universidad de los Andes, Bogota DC 111711, Colombia;
| | - Carlos E. Torres
- Department of Biomedical Engineering, Universidad de los Andes, Bogota DC 111711, Colombia; (C.E.T.); (S.C.G.); (L.A.G.); (C.M.-C.)
| | - Saúl C. Gómez
- Department of Biomedical Engineering, Universidad de los Andes, Bogota DC 111711, Colombia; (C.E.T.); (S.C.G.); (L.A.G.); (C.M.-C.)
| | - Laura A. Gómez
- Department of Biomedical Engineering, Universidad de los Andes, Bogota DC 111711, Colombia; (C.E.T.); (S.C.G.); (L.A.G.); (C.M.-C.)
| | - Juan C. Burgos
- Chemical Engineering Program, Universidad de Cartagena, Cartagena 130015, Colombia;
| | - Pablo Arbeláez
- Center for Research and Formation in Artificial Intelligence, Universidad de los Andes, Bogota DC 111711, Colombia; (P.R.P.); (P.A.)
- Department of Biomedical Engineering, Universidad de los Andes, Bogota DC 111711, Colombia; (C.E.T.); (S.C.G.); (L.A.G.); (C.M.-C.)
| | - Johann F. Osma
- Department of Electrical and Electronic Engineering, Universidad de los Andes, Bogota DC 111711, Colombia;
| | - Carolina Muñoz-Camargo
- Department of Biomedical Engineering, Universidad de los Andes, Bogota DC 111711, Colombia; (C.E.T.); (S.C.G.); (L.A.G.); (C.M.-C.)
| | - Luis H. Reyes
- Grupo de Diseño de Productos y Procesos, Department of Chemical and Food Engineering, Universidad de los Andes, Bogota DC 111711, Colombia;
| | - Juan C. Cruz
- Department of Biomedical Engineering, Universidad de los Andes, Bogota DC 111711, Colombia; (C.E.T.); (S.C.G.); (L.A.G.); (C.M.-C.)
- School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide 5005, Australia
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74
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Phosphatidylglyerol Lipid Binding at the Active Site of an Intramembrane Protease. J Membr Biol 2020; 253:563-576. [PMID: 33210155 PMCID: PMC7688093 DOI: 10.1007/s00232-020-00152-z] [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: 07/14/2020] [Accepted: 11/04/2020] [Indexed: 10/25/2022]
Abstract
Transmembrane substrate cleavage by the small Escherichia coli rhomboid protease GlpG informs on mechanisms by which lipid interactions shape reaction coordinates of membrane-embedded enzymes. Here, I review and discuss new work on the molecular picture of protein-lipid interactions that might govern the formation of the substrate-enzyme complex in fluid lipid membranes. Negatively charged PG-type lipids are of particular interest, because they are a major component of bacterial membranes. Atomistic computer simulations indicate POPG and DOPG lipids bridge remote parts of GlpG and might pre-occupy the substrate-docking site. Inhibition of catalytic activity by PG lipids could arise from ligand-like lipid binding at the active site, which could delay or prevent substrate docking. Dynamic protein-lipid H-bond networks, water access to the active site, and fluctuations in the orientation of GlpG suggest that GlpG has lipid-coupled dynamics that could shape the energy landscape of transmembrane substrate docking.
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75
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Casalino L, Gaieb Z, Goldsmith JA, Hjorth CK, Dommer AC, Harbison AM, Fogarty CA, Barros EP, Taylor BC, McLellan JS, Fadda E, Amaro RE. Beyond Shielding: The Roles of Glycans in the SARS-CoV-2 Spike Protein. ACS CENTRAL SCIENCE 2020; 6:1722-1734. [PMID: 33140034 PMCID: PMC7523240 DOI: 10.1021/acscentsci.0c01056] [Citation(s) in RCA: 572] [Impact Index Per Article: 143.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Indexed: 05/04/2023]
Abstract
The ongoing COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in more than 28,000,000 infections and 900,000 deaths worldwide to date. Antibody development efforts mainly revolve around the extensively glycosylated SARS-CoV-2 spike (S) protein, which mediates host cell entry by binding to the angiotensin-converting enzyme 2 (ACE2). Similar to many other viral fusion proteins, the SARS-CoV-2 spike utilizes a glycan shield to thwart the host immune response. Here, we built a full-length model of the glycosylated SARS-CoV-2 S protein, both in the open and closed states, augmenting the available structural and biological data. Multiple microsecond-long, all-atom molecular dynamics simulations were used to provide an atomistic perspective on the roles of glycans and on the protein structure and dynamics. We reveal an essential structural role of N-glycans at sites N165 and N234 in modulating the conformational dynamics of the spike's receptor binding domain (RBD), which is responsible for ACE2 recognition. This finding is corroborated by biolayer interferometry experiments, which show that deletion of these glycans through N165A and N234A mutations significantly reduces binding to ACE2 as a result of the RBD conformational shift toward the "down" state. Additionally, end-to-end accessibility analyses outline a complete overview of the vulnerabilities of the glycan shield of the SARS-CoV-2 S protein, which may be exploited in the therapeutic efforts targeting this molecular machine. Overall, this work presents hitherto unseen functional and structural insights into the SARS-CoV-2 S protein and its glycan coat, providing a strategy to control the conformational plasticity of the RBD that could be harnessed for vaccine development.
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Affiliation(s)
- Lorenzo Casalino
- Department
of Chemistry and Biochemistry, University
of California San Diego, La Jolla, California 92093, United States
| | - Zied Gaieb
- Department
of Chemistry and Biochemistry, University
of California San Diego, La Jolla, California 92093, United States
| | - Jory A. Goldsmith
- Department
of Molecular Biosciences, The University
of Texas at Austin, Austin, Texas 78712, United States
| | - Christy K. Hjorth
- Department
of Molecular Biosciences, The University
of Texas at Austin, Austin, Texas 78712, United States
| | - Abigail C. Dommer
- Department
of Chemistry and Biochemistry, University
of California San Diego, La Jolla, California 92093, United States
| | - Aoife M. Harbison
- Department
of Chemistry and Hamilton Institute, Maynooth
University, Dublin, Ireland
| | - Carl A. Fogarty
- Department
of Chemistry and Hamilton Institute, Maynooth
University, Dublin, Ireland
| | - Emilia P. Barros
- Department
of Chemistry and Biochemistry, University
of California San Diego, La Jolla, California 92093, United States
| | - Bryn C. Taylor
- Department
of Chemistry and Biochemistry, University
of California San Diego, La Jolla, California 92093, United States
- Biomedical
Sciences Graduate Program, University of
California San Diego, La Jolla, California 92093, United States
| | - Jason S. McLellan
- Department
of Molecular Biosciences, The University
of Texas at Austin, Austin, Texas 78712, United States
| | - Elisa Fadda
- Department
of Chemistry and Hamilton Institute, Maynooth
University, Dublin, Ireland
| | - Rommie E. Amaro
- Department
of Chemistry and Biochemistry, University
of California San Diego, La Jolla, California 92093, United States
- Biomedical
Sciences Graduate Program, University of
California San Diego, La Jolla, California 92093, United States
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76
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Casalino L, Gaieb Z, Goldsmith JA, Hjorth CK, Dommer AC, Harbison AM, Fogarty CA, Barros EP, Taylor BC, McLellan JS, Fadda E, Amaro RE. Beyond Shielding: The Roles of Glycans in SARS-CoV-2 Spike Protein. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020:2020.06.11.146522. [PMID: 32577644 PMCID: PMC7302197 DOI: 10.1101/2020.06.11.146522] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
Abstract
The ongoing COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in more than 15,000,000 infections and 600,000 deaths worldwide to date. Antibody development efforts mainly revolve around the extensively glycosylated SARS-CoV-2 spike (S) protein, which mediates the host cell entry by binding to the angiotensin-converting enzyme 2 (ACE2). Similar to many other viruses, the SARS-CoV-2 spike utilizes a glycan shield to thwart the host immune response. Here, we built a full-length model of glycosylated SARS-CoV-2 S protein, both in the open and closed states, augmenting the available structural and biological data. Multiple microsecond-long, all-atom molecular dynamics simulations were used to provide an atomistic perspective on the roles of glycans, and the protein structure and dynamics. We reveal an essential structural role of N-glycans at sites N165 and N234 in modulating the conformational dynamics of the spike's receptor binding domain (RBD), which is responsible for ACE2 recognition. This finding is corroborated by biolayer interferometry experiments, which show that deletion of these glycans through N165A and N234A mutations significantly reduces binding to ACE2 as a result of the RBD conformational shift towards the "down" state. Additionally, end-to-end accessibility analyses outline a complete overview of the vulnerabilities of the glycan shield of SARS-CoV-2 S protein, which may be exploited by therapeutic efforts targeting this molecular machine. Overall, this work presents hitherto unseen functional and structural insights into the SARS-CoV-2 S protein and its glycan coat, providing a strategy to control the conformational plasticity of the RBD that could be harnessed for vaccine development.
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Affiliation(s)
- Lorenzo Casalino
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA
| | - Zied Gaieb
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA
| | - Jory A. Goldsmith
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Christy K. Hjorth
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Abigail C. Dommer
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA
| | - Aoife M. Harbison
- Department of Chemistry and Hamilton Institute, Maynooth University, Dublin, Ireland
| | - Carl A. Fogarty
- Department of Chemistry and Hamilton Institute, Maynooth University, Dublin, Ireland
| | - Emilia P. Barros
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA
| | - Bryn C. Taylor
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA
- Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, CA, 92093, USA
| | | | - Elisa Fadda
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
- Department of Chemistry and Hamilton Institute, Maynooth University, Dublin, Ireland
| | - Rommie E. Amaro
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA
- Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, CA, 92093, USA
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77
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Kumar A, Cincotti A, Aparicio S. Insights into the interaction between lipid bilayers and trehalose aqueous solutions. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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78
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Blumer M, Harris S, Li M, Martinez L, Untereiner M, Saeta PN, Carpenter TS, Ingólfsson HI, Bennett WFD. Simulations of Asymmetric Membranes Illustrate Cooperative Leaflet Coupling and Lipid Adaptability. Front Cell Dev Biol 2020; 8:575. [PMID: 32850783 PMCID: PMC7396604 DOI: 10.3389/fcell.2020.00575] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 06/15/2020] [Indexed: 01/31/2023] Open
Abstract
Biological membranes are composed of lipid bilayers that are often asymmetric with regards to the lipid composition and/or aqueous solvent they separate. Studying lipid asymmetry both experimentally and computationally is challenging. Molecular dynamics simulations of lipid bilayers with asymmetry are difficult due to finite system sizes and time scales accessible to simulations. Due to the very slow flip-flop rate for phospholipids, one must first choose how many lipids are on each side of the bilayer, but the resulting bilayer may be unstable (or metastable) due to differing tensile and compressive forces between leaflets. Here we use molecular dynamics simulations to investigate a number of different asymmetric membrane systems, both with atomistic and coarse-grained models. Asymmetries studied include differences in number of lipids, lipid composition (unsaturated and saturated tails and different headgroups), and chemical gradients between the aqueous phases. Extensive analysis of the bilayers' properties such as area per lipid, density, and lateral pressure profiles are used to characterize bilayer asymmetry. We also address how cholesterol (which flip-flops relatively quickly) influences membrane asymmetries. Our results show how each leaflet is influenced by the other and can mitigate the structural changes to the bilayer overall structure. Cholesterol can respond to changes in bilayer asymmetry to alleviate some of the effect on the bilayer structure, but that will alter its leaflet distribution, which in turn affects its chemical potential. Ionic imbalances are shown to have a modest change in bilayer structure, despite large changes in the electrostatic potential. Bilayer asymmetry can also induce a modest electrostatic potential across the membrane. Our results highlight the importance of membrane asymmetry on bilayer properties, the influence of lipid headgroups, tails and cholesterol on asymmetry, and the ability of lipids to adapt to different environments.
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Affiliation(s)
- Madison Blumer
- Harvey Mudd College, Claremont, CA, United States.,Scripps College, Claremont, CA, United States
| | | | - Mengzhe Li
- Harvey Mudd College, Claremont, CA, United States.,Claremont McKenna College, Claremont, CA, United States
| | | | - Michael Untereiner
- Harvey Mudd College, Claremont, CA, United States.,Pomona College, Claremont, CA, United States
| | | | - Timothy S Carpenter
- Biochemical and Biophysical Systems Group, Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States
| | - Helgi I Ingólfsson
- Biochemical and Biophysical Systems Group, Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States
| | - W F Drew Bennett
- Biochemical and Biophysical Systems Group, Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States
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79
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Liu S, Zheng J, Hao L, Yegin Y, Bae M, Ulugun B, Taylor TM, Scholar EA, Cisneros-Zevallos L, Oh JK, Akbulut M. Dual-Functional, Superhydrophobic Coatings with Bacterial Anticontact and Antimicrobial Characteristics. ACS APPLIED MATERIALS & INTERFACES 2020; 12:21311-21321. [PMID: 32023023 DOI: 10.1021/acsami.9b18928] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Bacterial pathogens are responsible for millions of cases of illnesses and deaths each year throughout the world. The development of novel surfaces and coatings that effectively inhibit and prevent bacterial attachment, proliferation, and growth is one of the crucial steps for tackling this global challenge. Herein, we report a dual-functional coating for aluminum surfaces that relies on the controlled immobilization of lysozyme enzyme (muramidase) into interstitial spaces of presintered, nanostructured thin film based on ∼200 nm silica nanoparticles and the sequential chemisorption of an organofluorosilane to the available interfacial areas. The mean diameter of the resultant lysozyme microdomains was 3.1 ± 2.5 μm with an average spacing of 8.01 ± 6.8 μm, leading to a surface coverage of 15.32%. The coating had an overall root-mean-square (rms) roughness of 539 ± 137 nm and roughness factor of 1.50 ± 0.1, and demonstrated static, advancing, and receding water contact angles of 159.0 ± 1.0°, 155.4 ± 0.6°, and 154.4 ± 0.6°, respectively. Compared to the planar aluminum, the coated surfaces produced a 6.5 ± 0.1 (>99.99997%) and 4.0 ± 0.1 (>99.99%) log-cycle reductions in bacterial surfaces colonization against Gram-negative Salmonella Typhimurium LT2 and Gram-positive Listeria innocua, respectively. We anticipate that the implementation of such a coating strategy on healthcare environments and surfaces and food-contact surfaces can significantly reduce or eliminate potential risks associated with various contamination and cross-contamination scenarios.
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Affiliation(s)
- Shuhao Liu
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Jeremy Zheng
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Li Hao
- School of Chemistry and Chemical Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510408, People's Republic of China
| | - Yagmur Yegin
- Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843, United States
| | - Michael Bae
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Beril Ulugun
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Thomas Matthew Taylor
- Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843, United States
| | - Ethan A Scholar
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Luis Cisneros-Zevallos
- Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843, United States
- Department of Horticultural Sciences, Texas A&M University, College Station, Texas 77843, United States
| | - Jun Kyun Oh
- Department of Polymer Science and Engineering, Dankook University, 152 Jukjeon-ro, Suji-gu, Yongin-si, Gyeonggi-do 16890, Republic of Korea
| | - Mustafa Akbulut
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
- Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843, United States
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80
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Dehury B, Tang N, Blundell TL, Kepp KP. Structure and dynamics of γ-secretase with presenilin 2 compared to presenilin 1. RSC Adv 2019; 9:20901-20916. [PMID: 35515530 PMCID: PMC9065803 DOI: 10.1039/c9ra02623a] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 06/27/2019] [Indexed: 12/12/2022] Open
Abstract
Severe early-onset familial Alzheimer's disease (FAD) is caused by more than 200 different mutations in the genes coding for presenilin, the catalytic subunit of the 4-subunit protease complex γ-secretase, which cleaves the C99 fragment of the amyloid precursor protein (APP) to produce Aβ peptides. γ-Secretase exists with either of two homologues, PS1 and PS2. All cryo-electron microscopic structures and computational work has so far focused on γ-secretase with PS1, yet PS2 mutations also cause FAD. A central question is thus whether there are structural and dynamic differences between PS1 and PS2. To address this question, we use the cryo-electron microscopic data for PS1 to develop the first structural and dynamic model of PS2-γ-secretase in the catalytically relevant mature membrane-bound state at ambient temperature, equilibrated by three independent 500 ns molecular dynamics simulations. We find that the characteristic nicastrin extra-cellular domain breathing mode and major movements in the cytosolic loop between TM6 and TM7 occur in both PS2- and PS1-γ-secretase. The overall structures and conformational states are similar, suggesting similar catalytic activities. However, at the sequence level, charge-controlled membrane-anchoring is extracellular for PS1 and intracellular for PS2, which suggests different subcellular locations. The tilt angles of the TM2, TM6, TM7 and TM9 helices differ in the two forms of γ-secretase, suggesting that the two proteins have somewhat different substrate processing and channel sizes. Our MD simulations consistently indicated that PS2 retains several water molecules near the catalytic site at the bilayer, as required for catalysis. The possible reasons for the differences of PS1 and PS2 are discussed in relation to their location and function.
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Affiliation(s)
- Budheswar Dehury
- Department of Chemistry, Technical University of Denmark DK-2800 Kongens Lyngby Denmark +045 45252409
| | - Ning Tang
- Department of Chemistry, Technical University of Denmark DK-2800 Kongens Lyngby Denmark +045 45252409
| | - Tom L Blundell
- Department of Biochemistry, University of Cambridge Cambridge CB2 1GA UK
| | - Kasper P Kepp
- Department of Chemistry, Technical University of Denmark DK-2800 Kongens Lyngby Denmark +045 45252409
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