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Kurakin S, Badreeva D, Dushanov E, Shutikov A, Efimov S, Timerova A, Mukhametzyanov T, Murugova T, Ivankov O, Mamatkulov K, Arzumanyan G, Klochkov V, Kučerka N. Arrangement of lipid vesicles and bicelle-like structures formed in the presence of Aβ(25-35) peptide. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184237. [PMID: 37820938 DOI: 10.1016/j.bbamem.2023.184237] [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: 04/17/2023] [Revised: 08/31/2023] [Accepted: 10/03/2023] [Indexed: 10/13/2023]
Abstract
Our complementary experimental data and molecular dynamics (MD) simulations results reveal the structure of previously observed lipid bicelle-like structures (BLSs) formed in the presence of amyloid-beta peptide Aβ(25-35) below the main phase transition temperature (Tm) of saturated phosphatidylcholine lipids and small unilamellar vesicles (SUVs) above this temperature. First, we show by using solid-state 31P nuclear magnetic resonance (NMR) spectroscopy that our BLSs being in the lipid gel phase demonstrate magnetic alignment along the magnetic field of NMR spectrometer and undergo a transition to SUVs in the lipid fluid phase when heated through the Tm. Secondly, thanks to the BLS alignment we present their lipid structure. Lipids are found located not only in the flat bilayered part but also around its perimeter, which is corroborated by the results of coarse-grained (CG) MD simulations. Finally, peptides appear to mix randomly with lipids in SUVs while assuming predominantly unordered secondary structures revealed by circular dichroism (CD), Raman spectroscopy, and all-atom MD simulations. Importantly, the former is changing little when the system undergoes morphological transitions between BLSs and SUVs. Our structural results then offer a platform for studying and understanding mechanisms of morphological transformations caused by the disruptive effect of amyloid-beta peptides on the lipid bilayer.
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Affiliation(s)
- Sergei Kurakin
- Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna, Moscow Region 141980, Russia; Institute of Physics, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia.
| | - Dina Badreeva
- Meshcheryakov Laboratory of Information Technologies, Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna, Moscow Region 141980, Russia
| | - Ermuhammad Dushanov
- Laboratory of Radiation Biology, Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna, Moscow Region 141980, Russia
| | - Artyom Shutikov
- Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna, Moscow Region 141980, Russia
| | - Sergey Efimov
- Institute of Physics, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia
| | - Ayzira Timerova
- Institute of Physics, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia
| | - Timur Mukhametzyanov
- Butlerov Chemistry Institute, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia
| | - Tatiana Murugova
- Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna, Moscow Region 141980, Russia
| | - Oleksandr Ivankov
- Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna, Moscow Region 141980, Russia
| | - Kahramon Mamatkulov
- Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna, Moscow Region 141980, Russia
| | - Grigory Arzumanyan
- Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna, Moscow Region 141980, Russia
| | - Vladimir Klochkov
- Institute of Physics, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia
| | - Norbert Kučerka
- Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna, Moscow Region 141980, Russia; Department of Physical Chemistry of Drugs, Faculty of Pharmacy, Comenius University Bratislava, Odbojárov 10, Bratislava 832 32, Slovakia.
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2
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Qiang W, Kengwerere M, Zhao W, Scott FJ, Wutoh-Hughes X, Wang T, Mentink-Vigier F. Heterotypic Interactions between the 40- and 42-Residue Isoforms of β-Amyloid Peptides on Lipid Bilayer Surfaces. ACS Chem Neurosci 2023; 14:4153-4162. [PMID: 37991929 PMCID: PMC10867818 DOI: 10.1021/acschemneuro.3c00523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2023] Open
Abstract
Co-aggregation involving different amyloidogenic sequences has been emphasized recently in the modified amyloid cascade hypothesis. Yet, molecular-level interactions between two predominant β-amyloid peptide sequences, Aβ40 and Aβ42, in the fibrillation process in membrane-mimicked environments remain unclear. Here, we report biophysical evidence that demonstrates the molecular-level interactions between Aβ40 and Aβ42 at the membrane-associated conucleation stage using dynamic nuclear polarization-enhanced solid-state NMR spectroscopy. These residue-specific contacts are distinguished from those reported in mature fibrils formed by either Aβ40 or Aβ42. Meanwhile, site-specific interactions between Aβ and lipid molecules and modulation of microsecond-time-scale lipid dynamics are observed, which may be responsible for the more rapid and significant membrane content leakage compared to that with Aβ40 alone.
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Affiliation(s)
- Wei Qiang
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, NY 13902, USA
| | - Maurine Kengwerere
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, NY 13902, USA
| | - Wancheng Zhao
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Faith J. Scott
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Xyomara Wutoh-Hughes
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, NY 13902, USA
| | - Tuo Wang
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Frederic Mentink-Vigier
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
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3
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Wachira FW, Githirwa DC, McPartlon T, Nazarenko V, Gonzales JJC, Gazura MM, Leen C, Clary HR, Alston C, Klees LM, Yao L, An M. D-to-E and T19V Variants of the pH-Low Insertion Peptide and Their Doxorubicin Conjugates Interact with Membrane at Higher pH Ranges Than WT. Biochemistry 2023; 62:2997-3011. [PMID: 37793002 DOI: 10.1021/acs.biochem.3c00218] [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] [Indexed: 10/06/2023]
Abstract
To improve targeted cargo delivery to cancer cells, pH-Low Insertion Peptide (pHLIP) variants were developed to interact with the membrane at pH values higher than those of the WT. The Asp-to-Glu variants aim to increase side chain pKa without disturbing the sequence of protonations that underpin membrane insertion. The Thr19 variants represent efforts to perturb the critical Pro20 residue. To study the effect of cargo on pHLIP insertion, doxorubicin (Dox), a fluorescent antineoplastic drug, was conjugated to selected variants near the inserting C-terminus. Variants and conjugates were characterized on a POPC membrane using Trp and Dox fluorescence methods to define the entire pH range of insertion (pHinitial-pHfinal). Compared to WT with a pHi-pHf range of 6.7-5.6, D25E-D31E-D33E, D14E-D25E-D31E-D33E, and T19V-D25E variants demonstrated higher pHi-pHf ranges of 7.3-6.1, 7.3-6.3, and 8.2-5.4, respectively. The addition of Dox expanded the pHi-pHf range, mainly by shifting pHi to higher pH values (e.g., WT pHLIP-Dox has a pHi-pHf range of 7.7-5.2). Despite the low Hill coefficient observed for the conjugates, D14E-D25E-D31E-D33E pHLIP-Dox completed insertion by a pHf of 5.7. However, the Dox cargo remained in the hydrophobic membrane interior after pHLIP insertion, which may impede drug release. Finally, a logistic function can describe pHLIP insertion as a peripheral-to-TM (start-to-finish) two-state transition; wherever possible, we discuss data deviating from such sigmoidal fitting in support of the idea that pH-specific intermediate states distinct from the initial peripheral state and the final TM state exist at intervening pH values.
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Affiliation(s)
- Faith W Wachira
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Dancan C Githirwa
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Thomas McPartlon
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Vladyslav Nazarenko
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Jerel J C Gonzales
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Makenzie M Gazura
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Caitlin Leen
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Hannah R Clary
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Claire Alston
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Lukas M Klees
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Lan Yao
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
- Department of Physics, SUNY, Binghamton University, Binghamton, New York 13902, United States
| | - Ming An
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
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Kim M, Bezprozvanny I. Potential direct role of synuclein in dopamine transport and its implications for Parkinson's disease pathogenesis. Biochem Biophys Res Commun 2023; 671:18-25. [PMID: 37290280 DOI: 10.1016/j.bbrc.2023.05.110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 05/25/2023] [Indexed: 06/10/2023]
Abstract
Parkinson Disease (PD) is a progressive neurodegenerative disorder that is caused by dysfunction and death of dopaminergic neurons. Mutations in the gene encoding α-synuclein (ASYN) have been linked with familial PD (FPD). Despite important role of ASYN in PD pathology, its normal biological function has not been clarified, although direct action of ASYN in synaptic transmission and dopamine (DA+) release have been proposed. In the present report we propose a novel hypothesis that ASYN functions as DA+/H+ exchanger that can facilitate transport of dopamine across synaptic vesicle (SV) membrane by taking advantage of proton gradient between SV lumen and cytoplasm. According to this hypothesis, normal physiological role of ASYN consists of fine-tuning levels of dopamine in the SVs based on cytosolic concentration of dopamine and intraluminal pH. This hypothesis is based on similarity in domain structure of ASYN and pHILP, a designed peptide developed to mediate loading of lipid nanoparticles with the cargo molecules. We reason that carboxy-terminal acidic loop D2b domain in both ASYN and pHILP binds cargo molecules. By mimicking DA+ association with E/D residues in D2b domain of ASYN using Tyrosine replacement approach (TR) we have been able to estimate that ASYN is able to transfer 8-12 molecules of dopamine across SV membrane on each DA+/H+ exchange cycle. Our results suggest that familial PD mutations (A30P, E46K, H50Q, G51D, A53T and A53E) will interfere with different steps of the exchange cycle, resulting in partial loss of dopamine transport function phenotype. We also predict that similar impairment in ASYN DA+/H+ exchange function also occurs as a result on neuronal aging due to changes in SV lipid composition and size and also dissipation of pH gradient across SV membrane. Proposed novel functional role of ASYN provides novel insights into its biological role and its role in PD pathogenesis.
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Affiliation(s)
- Meewhi Kim
- Dept of Physiology, UT Southwestern Medical Center, Dallas, TX, 75390, USA.
| | - Ilya Bezprozvanny
- Dept of Physiology, UT Southwestern Medical Center, Dallas, TX, 75390, USA; Laboratory of Molecular Neurodegeneration, St Petersburg State Polytechnical Universty, St Petersburg, 195251, Russian Federation.
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5
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Visca H, DuPont M, Moshnikova A, Crawford T, Engelman DM, Andreev OA, Reshetnyak YK. pHLIP Peptides Target Acidity in Activated Macrophages. Mol Imaging Biol 2022; 24:874-885. [PMID: 35604527 PMCID: PMC9681937 DOI: 10.1007/s11307-022-01737-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/19/2022] [Accepted: 04/27/2022] [Indexed: 12/29/2022]
Abstract
PURPOSE Acidity can be a useful alternative biomarker for the targeting of metabolically active cells in certain diseased tissues, as in acute inflammation or aggressive tumors. We investigated the targeting of activated macrophages by pH low insertion peptides (pHLIPs), an established technology for targeting cell-surface acidity. PROCEDURES The uptake of fluorescent pHLIPs by activated macrophages was studied in cell cultures, in a mouse model of lung inflammation, and in a mouse tumor model. Fluorescence microscopy, whole-body and organ imaging, immunohistochemistry, and FACS analysis were employed. RESULTS We find that cultured, activated macrophages readily internalize pHLIPs. The uptake is higher in glycolytic macrophages activated by LPS and INF-γ compared to macrophages activated by IL-4/IL-13. Fluorescent pHLIPs target LPS-induced lung inflammation in mice. In addition to marking cancer cells within the tumor microenvironment, fluorescent pHLIPs target CD45+, CD11b+, F4/80+, and CD206+ tumor-associated macrophages with no significant targeting of other immune cells. Also, fluorescent pHLIPs target CD206-positive cells found in the inguinal lymph nodes of animals inoculated with breast cancer cells in mammary fat pads. CONCLUSIONS pHLIP peptides sense low cell surface pH, which triggers their insertion into the cell membrane. Unlike cancerous cells, activated macrophages do not retain inserted pHLIPs on their surfaces, instead their highly active membrane recycling moves the pHLIPs into endosomes. Targeting activated macrophages in diseased tissues may enable clinical visualization and therapeutic opportunities.
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Affiliation(s)
- Hannah Visca
- Physics Department, University of Rhode Island, Kingston, RI, USA
| | - Michael DuPont
- Physics Department, University of Rhode Island, Kingston, RI, USA
| | - Anna Moshnikova
- Physics Department, University of Rhode Island, Kingston, RI, USA
| | - Troy Crawford
- Physics Department, University of Rhode Island, Kingston, RI, USA
| | - Donald M Engelman
- Department of Molecular Biophysics and Biochemistry, Yale, New Haven, CT, USA
| | - Oleg A Andreev
- Physics Department, University of Rhode Island, Kingston, RI, USA
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6
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Ataka K, Drauschke J, Stulberg V, Koksch B, Heberle J. pH-induced insertion of pHLIP into a lipid bilayer: In-situ SEIRAS characterization of a folding intermediate at neutral pH. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183873. [PMID: 35104491 DOI: 10.1016/j.bbamem.2022.183873] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 11/22/2021] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
The pH low insertion peptide (pHLIP) is a pH-sensitive cell penetrating peptide that transforms from an unstructured coil on the membrane surface at pH > 7, to a transmembrane (TM) α-helix at pH < 5. By exploiting this unique property, pHLIP attracts interest as a potential tool for drug delivery and visualisation of acidic tissues produced by various maladies such as cancer, inflammation, hypoxia etc. Even though the structures of initial and end states of pHLIP insertion have been widely accepted, the intermediate structures in between these two states are less clear. Here, we have applied in situ Surface-Enhanced Infrared Absorption spectroscopy to examine the pH-induced insertion and folding processes of pHLIP into a solid-supported lipid bilayer. We show that formation of partially helical structure already takes place at pH only slightly below 7.0, but with the helical axis parallel to the membrane surface. The peptide starts to reorientate its helix from horizontal to vertical direction, accompanied by the insertion into the TM region at pH < 6.2. Further insertion into the TM region of the peptide results in an increase of inherent α-helical structure and complete secondary structure formation at pH 5.3. Analysis of the changes of the carboxylate vibrational bands upon pH titration shows two distinctive groups of aspartates and glutamates with pKa values of 4.5 and 6.3, respectively. Comparison to the amide bands of the peptide backbone suggests that the latter Asp/Glu groups are directly involved in the conformational changes of pHLIP in the respective intermediate states.
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Affiliation(s)
- Kenichi Ataka
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
| | - Janina Drauschke
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Valentina Stulberg
- Institute for Chemistry and Biochemistry, Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Arnimallee 20, 14195, Berlin, Germany
| | - Beate Koksch
- Institute for Chemistry and Biochemistry, Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Arnimallee 20, 14195, Berlin, Germany
| | - Joachim Heberle
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
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Otieno SA, Qiang W. Roles of key residues and lipid dynamics reveal pHLIP-membrane interactions at intermediate pH. Biophys J 2021; 120:4649-4662. [PMID: 34624273 PMCID: PMC8595900 DOI: 10.1016/j.bpj.2021.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 09/16/2021] [Accepted: 10/01/2021] [Indexed: 11/16/2022] Open
Abstract
The pH-low insertion peptide (pHLIP) and its analogs sense the microenvironmental pH variations in tumorous cells and serve as useful anticancer drug deliveries. The pHLIP binds peripherally to membranes and adopts random coil conformation at the physiological pH. The peptide switches from random coil to α-helical conformation and inserts unidirectionally into membrane bilayers when pH drops below a critical transition value that has been routinely determined by the Trp fluorescence spectroscopy. Recent high-resolution studies using solid-state NMR spectroscopy revealed the presence of thermodynamically stable intermediate states of membrane-associated pHLIP around the fluorescence-based transition pH-value. However, the molecular structural features and their mechanistic roles of these intermediate states in the pH-driven membrane insertion process of pHLIP remain largely unknown. This work utilizes solid-state NMR spectroscopy to explore 1) the mechanistic roles of key proline and arginine residues within the pHLIP sequence at intermediate pH-values, and 2) the changes in lipid dynamics at intermediate pH-values in multiple types of model bilayers with anionic phospholipid and/or cholesterol. Our results demonstrate several molecular structural and dynamics changes at around the transition pH-values, including the isomerization of proline-threonine backbone configuration, breaking of arginine-aspartic acid salt bridge and the formation of arginine-lipid interactions, and a universal decreasing of dynamics in lipid headgroups and alkyl chains. Overall, the outcomes provide important insights on the molecular interactions between pHLIP and membrane bilayers at intermediate pH-values and, therefore, prompt the understanding of pH-driven membrane insertion process of this anticancer drug-delivering peptide.
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Affiliation(s)
- Sarah A Otieno
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, New York
| | - Wei Qiang
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, New York.
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8
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Kim SY, Bondar AN, Wimley WC, Hristova K. pH-triggered pore-forming peptides with strong composition-dependent membrane selectivity. Biophys J 2021; 120:618-630. [PMID: 33460594 PMCID: PMC7896028 DOI: 10.1016/j.bpj.2021.01.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 12/06/2020] [Accepted: 01/04/2021] [Indexed: 12/21/2022] Open
Abstract
Peptides that self-assemble into nanometer-sized pores in lipid bilayers could have utility in a variety of biotechnological and clinical applications if we can understand their physical chemical properties and learn to control their membrane selectivity. To empower such control, we have used synthetic molecular evolution to identify the pH-dependent delivery peptides, a family of peptides that assemble into macromolecule-sized pores in membranes at low peptide concentration but only at pH < ∼6. Further advancements will also require better selectivity for specific membranes. Here, we determine the effect of anionic headgroups and bilayer thickness on the mechanism of action of the pH-dependent delivery peptides by measuring binding, secondary structure, and macromolecular poration. The peptide pHD15 partitions and folds equally well into zwitterionic and anionic membranes but is less potent at pore formation in phosphatidylserine-containing membranes. The peptide also binds and folds similarly in membranes of various thicknesses, but its ability to release macromolecules changes dramatically. It causes potent macromolecular poration in vesicles made from phosphatidylcholine with 14 carbon acyl chains, but macromolecular poration decreases sharply with increasing bilayer thickness and does not occur at any peptide concentration in fluid bilayers made from phosphatidylcholine lipids with 20-carbon acyl chains. The effects of headgroup and bilayer thickness on macromolecular poration cannot be accounted for by the amount of peptide bound but instead reflect an inherent selectivity of the peptide for inserting into the membrane-spanning pore state. Molecular dynamics simulations suggest that the effect of thickness is due to hydrophobic match/mismatch between the membrane-spanning peptide and the bilayer hydrocarbon. This remarkable degree of selectivity based on headgroup and especially bilayer thickness is unusual and suggests ways that pore-forming peptides with exquisite selectivity for specific membranes can be designed or evolved.
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Affiliation(s)
- Sarah Y Kim
- Department of Materials Science and Engineering, Institute for NanoBioTechnology, and Program in Molecular Biophysics, Johns Hopkins University, Baltimore, Maryland
| | - Ana-Nicoleta Bondar
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics Group, Berlin, Germany.
| | - William C Wimley
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana.
| | - Kalina Hristova
- Department of Materials Science and Engineering, Institute for NanoBioTechnology, and Program in Molecular Biophysics, Johns Hopkins University, Baltimore, Maryland.
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Chorev DS, Robinson CV. The importance of the membrane for biophysical measurements. Nat Chem Biol 2020; 16:1285-1292. [PMID: 33199903 PMCID: PMC7116504 DOI: 10.1038/s41589-020-0574-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 05/22/2020] [Indexed: 11/09/2022]
Abstract
Within cell membranes numerous protein assemblies reside. Among their many functions, these assemblies regulate the movement of molecules between membranes, facilitate signaling into and out of cells, allow movement of cells by cell-matrix attachment, and regulate the electric potential of the membrane. With such critical roles, membrane protein complexes are of considerable interest for human health, yet they pose an enduring challenge for structural biologists because it is difficult to study these protein structures at atomic resolution in in situ environments. To advance structural and functional insights for these protein assemblies, membrane mimetics are typically employed to recapitulate some of the physical and chemical properties of the lipid bilayer membrane. However, extraction from native membranes can sometimes change the structure and lipid-binding properties of these complexes, leading to conflicting results and fueling a drive to study complexes directly from native membranes. Here we consider the co-development of membrane mimetics with technological breakthroughs in both cryo-electron microscopy (cryo-EM) and native mass spectrometry (nMS). Together, these developments are leading to a plethora of high-resolution protein structures, as well as new knowledge of their lipid interactions, from different membrane-like environments.
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Affiliation(s)
- Dror S Chorev
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, UK
| | - Carol V Robinson
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, UK.
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10
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Burns V, Mertz B. Using Simulation to Understand the Role of Titration on the Stability of a Peptide-Lipid Bilayer Complex. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:12272-12280. [PMID: 32988206 PMCID: PMC7778881 DOI: 10.1021/acs.langmuir.0c02038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The pH-low insertion peptide (pHLIP) is an anionic membrane-active peptide with promising potential for applications in imaging of cancer tumors and targeted delivery of chemotherapeutics. The key advantage of pHLIP lies in its acid sensitivity: in acidic cellular environments, pHLIP can insert unidirectionally into the plasma membrane. Partitioning-folding coupling is triggered by titration of the acidic residues in pHLIP, transforming pHLIP from a hydrophilic to a hydrophobic peptide. Despite this knowledge, the reverse pathway that leads to exit of the peptide from the plasma membrane is poorly understood. Our hypothesis is that sequential deprotonation of pHLIP is a prerequisite for exit of the peptide from the plasma membrane. We carried out molecular dynamics (MD) simulations to characterize the effect that deprotonation of the acidic residues of pHLIP has on the stability of the peptide when inserted into a model lipid bilayer of 1-palmitoyl-2-oleoyl-sn-3-phosphocholine (POPC). Initiation of the exit mechanism is facilitated by a complex relationship between the peptide, bulk solvent, and the membrane environment. As the N-terminal acidic residues of pHLIP are deprotonated, localized loss of helicity drives unfolding of the peptide and more pronounced interactions with the bilayer at the lipid-water interface. Deprotonation of the C-terminal acidic residues (D25, D31, D33, and E34) leads to further loss of secondary structure distal from the C-terminus, as well as formation of a water channel that stabilizes the orientation of pHLIP parallel to the membrane normal. Together, these results help explain how stabilization of intermediates between the surface-bound and inserted states of pHLIP occur and provide insights into rational design of pHLIP variants with modified abilities of insertion.
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Affiliation(s)
- Violetta Burns
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Blake Mertz
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
- WVU Cancer Institute, West Virginia University, Morgantown, West Virginia 26506, United States
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11
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Schäfer AB, Wenzel M. A How-To Guide for Mode of Action Analysis of Antimicrobial Peptides. Front Cell Infect Microbiol 2020; 10:540898. [PMID: 33194788 PMCID: PMC7604286 DOI: 10.3389/fcimb.2020.540898] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 09/18/2020] [Indexed: 12/11/2022] Open
Abstract
Antimicrobial peptides (AMPs) are a promising alternative to classical antibiotics in the fight against multi-resistant bacteria. They are produced by organisms from all domains of life and constitute a nearly universal defense mechanism against infectious agents. No drug can be approved without information about its mechanism of action. In order to use them in a clinical setting, it is pivotal to understand how AMPs work. While many pore-forming AMPs are well-characterized in model membrane systems, non-pore-forming peptides are often poorly understood. Moreover, there is evidence that pore formation may not happen or not play a role in vivo. It is therefore imperative to study how AMPs interact with their targets in vivo and consequently kill microorganisms. This has been difficult in the past, since established methods did not provide much mechanistic detail. Especially, methods to study membrane-active compounds have been scarce. Recent advances, in particular in microscopy technology and cell biological labeling techniques, now allow studying mechanisms of AMPs in unprecedented detail. This review gives an overview of available in vivo methods to investigate the antibacterial mechanisms of AMPs. In addition to classical mode of action classification assays, we discuss global profiling techniques, such as genomic and proteomic approaches, as well as bacterial cytological profiling and other cell biological assays. We cover approaches to determine the effects of AMPs on cell morphology, outer membrane, cell wall, and inner membrane properties, cellular macromolecules, and protein targets. We particularly expand on methods to examine cytoplasmic membrane parameters, such as composition, thickness, organization, fluidity, potential, and the functionality of membrane-associated processes. This review aims to provide a guide for researchers, who seek a broad overview of the available methodology to study the mechanisms of AMPs in living bacteria.
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Affiliation(s)
| | - Michaela Wenzel
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
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12
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Rajab IM, Majerczyk D, Olson ME, Addams JMB, Choe ML, Nelson MS, Potempa LA. C-reactive protein in gallbladder diseases: diagnostic and therapeutic insights. BIOPHYSICS REPORTS 2020. [DOI: 10.1007/s41048-020-00108-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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13
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Abstract
To advance mechanistic understanding of membrane-associated peptide folding and insertion, we have studied the kinetics of three single tryptophan pHLIP (pH-Low Insertion Peptide) variants, where tryptophan residues are located near the N terminus, near the middle, and near the inserting C-terminal end of the pHLIP transmembrane helix. Single-tryptophan pHLIP variants allowed us to probe different parts of the peptide in the pathways of peptide insertion into the lipid bilayer (triggered by a pH drop) and peptide exit from the bilayer (triggered by a rise in pH). By using pH jumps of different magnitudes, we slowed down the processes and established the intermediates that helped us to understand the principles of insertion and exit. The obtained results should also aid the applications in medicine that are now entering the clinic.
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14
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Reshetnyak YK, Moshnikova A, Andreev OA, Engelman DM. Targeting Acidic Diseased Tissues by pH-Triggered Membrane-Associated Peptide Folding. Front Bioeng Biotechnol 2020; 8:335. [PMID: 32411684 PMCID: PMC7198868 DOI: 10.3389/fbioe.2020.00335] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 03/26/2020] [Indexed: 12/19/2022] Open
Abstract
The advantages of targeted therapy have motivated many efforts to find distinguishing features between the molecular cell surface landscapes of diseased and normal cells. Typically, the features have been proteins, lipids or carbohydrates, but other approaches are emerging. In this discussion, we examine the use of cell surface acidity as a feature that can be exploited by using pH-sensitive peptide folding to target agents to diseased cell surfaces or cytoplasms.
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Affiliation(s)
- Yana K Reshetnyak
- Department of Physics, The University of Rhode Island, Kingston, RI, United States
| | - Anna Moshnikova
- Department of Physics, The University of Rhode Island, Kingston, RI, United States
| | - Oleg A Andreev
- Department of Physics, The University of Rhode Island, Kingston, RI, United States
| | - Donald M Engelman
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
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15
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Belluati A, Mikhalevich V, Yorulmaz Avsar S, Daubian D, Craciun I, Chami M, Meier WP, Palivan CG. How Do the Properties of Amphiphilic Polymer Membranes Influence the Functional Insertion of Peptide Pores? Biomacromolecules 2019; 21:701-715. [DOI: 10.1021/acs.biomac.9b01416] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Andrea Belluati
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4058 Basel, Switzerland
| | - Viktoria Mikhalevich
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4058 Basel, Switzerland
| | - Saziye Yorulmaz Avsar
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4058 Basel, Switzerland
| | - Davy Daubian
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4058 Basel, Switzerland
| | - Ioana Craciun
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4058 Basel, Switzerland
| | - Mohamed Chami
- BioEM Lab, Biozentrum, University of Basel, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Wolfgang P. Meier
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4058 Basel, Switzerland
| | - Cornelia G. Palivan
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4058 Basel, Switzerland
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16
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Rao BD, Chakraborty H, Chaudhuri A, Chattopadhyay A. Differential sensitivity of pHLIP to ester and ether lipids. Chem Phys Lipids 2019; 226:104849. [PMID: 31836521 DOI: 10.1016/j.chemphyslip.2019.104849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 12/05/2019] [Accepted: 12/05/2019] [Indexed: 10/25/2022]
Abstract
pH (low) insertion peptide (pHLIP) is a polypeptide from the third transmembrane helix of bacteriorhodopsin. The pH-dependent membrane insertion of pHLIP has been conveniently exploited for translocation of cargo molecules and as a novel imaging agent in cancer biology due to low extracellular pH in cancer tissues. Although the application of pHLIP for imaging tumor and targeted drug delivery is well studied, literature on pHLIP-membrane interaction is relatively less studied. Keeping this in mind, we explored the differential interaction of pHLIP with ester and ether lipid membranes utilizing fluorescence and CD spectroscopy. We report, for the first time, higher binding affinity of pHLIP toward ether lipid relative to ester lipid membranes. There results gain relevance since Halobacterium halobium (source of bacteriorhodopsin) is enriched with ether lipids. In addition, we monitored the difference in microenvironment around pHLIP tryptophans utilizing red edge excitation shift and observed increased motional restriction of water molecules in the interfacial region in ether lipid membranes. These changes were accompanied with increase in helicity of pHLIP in ether lipid relative to ester lipid membranes. Our results assume further relevance since ether lipids are upregulated in cancer cells and have emerged as potential biomarkers of various diseases including cancer.
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Affiliation(s)
- Bhagyashree D Rao
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India; CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad, 500 007, India; Academy of Scientific and Innovative Research, Ghaziabad, 201 002, India
| | - Hirak Chakraborty
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India; School of Chemistry, Sambalpur University, Jyoti Vihar, Burla, Odisha, 768 019, India
| | - Arunima Chaudhuri
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India
| | - Amitabha Chattopadhyay
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India; Academy of Scientific and Innovative Research, Ghaziabad, 201 002, India.
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17
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Vasquez-Montes V, Gerhart J, Thévenin D, Ladokhin AS. Divalent Cations and Lipid Composition Modulate Membrane Insertion and Cancer-Targeting Action of pHLIP. J Mol Biol 2019; 431:5004-5018. [PMID: 31689432 PMCID: PMC6920566 DOI: 10.1016/j.jmb.2019.10.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 10/24/2019] [Accepted: 10/24/2019] [Indexed: 02/06/2023]
Abstract
The pH-Low Insertion Peptide (pHLIP) has emerged as an important tool for targeting cancer cells; it has been assumed that its targeting mechanism depends solely on the mild acidic environment surrounding tumors. Here, we examine the role of Ca2+ and Mg2+ on pHLIP's insertion, cellular targeting, and drug delivery. We demonstrate that physiologically relevant concentrations of either cation can shift the protonation-dependent transition by up to several pH units toward basic pH and induce substantial protonation-independent transmembrane insertion of pHLIP at pH as high as 10. Consistent with these results, the ability of pHLIP to deliver the cytotoxic compound monomethyl-auristatin-F to HeLa cells is increased several fold in presence of Ca2+. Complementary measurements with model membranes confirmed this Ca2+/Mg2+-dependent membrane-insertion mechanism. The magnitude of this alternative Ca2+/Mg2+-dependent effect is also modulated by lipid composition-specifically by the presence of phosphatidylserine-providing new clues to pHLIP's unique tumor-targeting ability in vivo. These results exemplify the complex coupling between protonation of anionic residues and lipid-selective targeting by divalent cations, which is relevant to the general signaling on membrane interfaces.
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Affiliation(s)
- Victor Vasquez-Montes
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Janessa Gerhart
- Department of Chemistry, Lehigh University, 6 East Packer Avenue, Bethlehem, PA, 18015, USA
| | - Damien Thévenin
- Department of Chemistry, Lehigh University, 6 East Packer Avenue, Bethlehem, PA, 18015, USA
| | - Alexey S Ladokhin
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, KS, 66160, USA.
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18
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Wilson BA, Ramanathan A, Lopez CF. Cardiolipin-Dependent Properties of Model Mitochondrial Membranes from Molecular Simulations. Biophys J 2019; 117:429-444. [PMID: 31349988 PMCID: PMC6697365 DOI: 10.1016/j.bpj.2019.06.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 06/17/2019] [Accepted: 06/24/2019] [Indexed: 01/30/2023] Open
Abstract
Cardiolipin is an anionic lipid found in the mitochondrial membranes of eukaryotes ranging from unicellular microorganisms to metazoans. This unique lipid contributes to various mitochondrial functions, including metabolism, mitochondrial membrane fusion and/or fission dynamics, and apoptosis. However, differences in cardiolipin content between the two mitochondrial membranes, as well as dynamic fluctuations in cardiolipin content in response to stimuli and cellular signaling events, raise questions about how cardiolipin concentration affects mitochondrial membrane structure and dynamics. Although cardiolipin’s structural and dynamic roles have been extensively studied in binary mixtures with other phospholipids, the biophysical properties of cardiolipin in higher number lipid mixtures are still not well resolved. Here, we used molecular dynamics simulations to investigate the cardiolipin-dependent properties of ternary lipid bilayer systems that mimic the major components of mitochondrial membranes. We found that changes to cardiolipin concentration only resulted in minor changes to bilayer structural features but that the lipid diffusion was significantly affected by those alterations. We also found that cardiolipin position along the bilayer surfaces correlated to negative curvature deflections, consistent with the induction of negative curvature stress in the membrane monolayers. This work contributes to a foundational understanding of the role of cardiolipin in altering the properties in ternary lipid mixtures composed of the major mitochondrial phospholipids, providing much-needed insights to help understand how cardiolipin concentration modulates the biophysical properties of mitochondrial membranes.
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Affiliation(s)
- Blake A Wilson
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee
| | - Arvind Ramanathan
- Computational Science and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee; Health Data Sciences Institute, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Carlos F Lopez
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee; Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, Tennessee; Department of Pharmacology, Vanderbilt University, Nashville, Tennessee.
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19
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Marinko J, Huang H, Penn WD, Capra JA, Schlebach JP, Sanders CR. Folding and Misfolding of Human Membrane Proteins in Health and Disease: From Single Molecules to Cellular Proteostasis. Chem Rev 2019; 119:5537-5606. [PMID: 30608666 PMCID: PMC6506414 DOI: 10.1021/acs.chemrev.8b00532] [Citation(s) in RCA: 160] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Indexed: 12/13/2022]
Abstract
Advances over the past 25 years have revealed much about how the structural properties of membranes and associated proteins are linked to the thermodynamics and kinetics of membrane protein (MP) folding. At the same time biochemical progress has outlined how cellular proteostasis networks mediate MP folding and manage misfolding in the cell. When combined with results from genomic sequencing, these studies have established paradigms for how MP folding and misfolding are linked to the molecular etiologies of a variety of diseases. This emerging framework has paved the way for the development of a new class of small molecule "pharmacological chaperones" that bind to and stabilize misfolded MP variants, some of which are now in clinical use. In this review, we comprehensively outline current perspectives on the folding and misfolding of integral MPs as well as the mechanisms of cellular MP quality control. Based on these perspectives, we highlight new opportunities for innovations that bridge our molecular understanding of the energetics of MP folding with the nuanced complexity of biological systems. Given the many linkages between MP misfolding and human disease, we also examine some of the exciting opportunities to leverage these advances to address emerging challenges in the development of therapeutics and precision medicine.
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Affiliation(s)
- Justin
T. Marinko
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Hui Huang
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Wesley D. Penn
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - John A. Capra
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
- Department
of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37245, United States
| | - Jonathan P. Schlebach
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Charles R. Sanders
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
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20
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Wenzel M, Vischer NOE, Strahl H, Hamoen LW. Assessing Membrane Fluidity and Visualizing Fluid Membrane Domains in Bacteria Using Fluorescent Membrane Dyes. Bio Protoc 2018; 8:e3063. [PMID: 34532528 DOI: 10.21769/bioprotoc.3063] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 10/06/2018] [Accepted: 10/29/2018] [Indexed: 11/02/2022] Open
Abstract
Membrane fluidity is a key parameter of bacterial membranes that undergoes quick adaptation in response to environmental challenges and has recently emerged as an important factor in the antibacterial mechanism of membrane-targeting antibiotics. The specific level of membrane fluidity is not uniform across the bacterial cell membrane. Rather, specialized microdomains associated with different cellular functions can exhibit fluidity values that significantly deviate from the average. Assessing changes in the overall membrane fluidity and formation of membrane microdomains is therefore pivotal to understand both the functional organization of the bacterial cell membrane as well as antibiotic mechanisms. Here we describe how two fluorescent membrane dyes, laurdan and DiIC12, can be employed to assess membrane fluidity in living bacteria. We focus on Bacillus subtilis, since this organism has been relatively well-studied with respect to membrane domains. However, we also describe how these assays can be adapted for other bacteria such as Staphylococcus aureus and Streptococcus pneumoniae.
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Affiliation(s)
- Michaela Wenzel
- Bacterial Cell Biology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands.,Department of Medical Microbiology and Infection Control, Amsterdam University Medical Centers, Location VUMC, Amsterdam, The Netherlands
| | - Norbert O E Vischer
- Bacterial Cell Biology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Henrik Strahl
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Leendert W Hamoen
- Bacterial Cell Biology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
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