1
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Sani MA, Le Brun AP, Rajput S, Attard T, Separovic F. The membrane activity of the antimicrobial peptide caerin 1.1 is pH dependent. Biophys J 2023; 122:1058-1067. [PMID: 36680343 PMCID: PMC10111263 DOI: 10.1016/j.bpj.2023.01.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 12/09/2022] [Accepted: 01/18/2023] [Indexed: 01/22/2023] Open
Abstract
Antimicrobial peptides are an important class of membrane-active peptides that can provide alternatives or complements to classic antibiotics. Among the many classes of AMPs, the histidine-rich family is of particular interest since they may induce pH-sensitive interactions with cell membranes. The AMP caerin 1.1 (Cae-1), from Australian tree frogs, has three histidine residues, and thus we studied the pH dependence of its interactions with model cell membranes. Using NMR spectroscopy and molecular dynamics simulations, we showed that Cae-1 induced greater perturbation of the lipid dynamics and water penetrations within the membrane interior in an acidic environment compared with physiological conditions. Using 31P solid-state NMR, the packing, chemical environment, and dynamics of the lipid headgroup were monitored. 2H solid-state NMR showed that Cae-1 ordered the acyl chains of the hydrophobic core of the bilayer. These results supported the molecular dynamics data, which showed that Cae-1 was mainly inserted within the lipid bilayer for both neutral and negatively charged membranes, with the charged residues pulling the water and phosphate groups inward. This could be an early step in the mechanism of membrane disruption by histidine-rich antimicrobial peptides and indicated that Cae-1 acts via a transmembrane mechanism in bilayers of neutral and anionic phospholipid membranes, especially in acidic conditions.
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Affiliation(s)
- Marc-Antoine Sani
- Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia.
| | - Anton P Le Brun
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Kirrawee, New South Wales, Australia
| | - Sunnia Rajput
- Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Troy Attard
- Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Frances Separovic
- Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia; School of Chemistry, University of Melbourne, Melbourne, Victoria, Australia.
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2
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Booth V. Deuterium Solid State NMR Studies of Intact Bacteria Treated With Antimicrobial Peptides. FRONTIERS IN MEDICAL TECHNOLOGY 2022; 2:621572. [PMID: 35047897 PMCID: PMC8757836 DOI: 10.3389/fmedt.2020.621572] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 12/10/2020] [Indexed: 11/13/2022] Open
Abstract
Solid state NMR has been tremendously useful in characterizing the structure and dynamics of model membranes composed of simple lipid mixtures. Model lipid studies employing solid state NMR have included important work revealing how membrane bilayer structure and dynamics are affected by molecules such as antimicrobial peptides (AMPs). However, solid state NMR need not be applied only to model membranes, but can also be used with living, intact cells. NMR of whole cells holds promise for helping resolve some unsolved mysteries about how bacteria interact with AMPs. This mini-review will focus on recent studies using 2H NMR to study how treatment with AMPs affect membranes in intact bacteria.
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Affiliation(s)
- Valerie Booth
- Department of Biochemistry and Department of Physics and Physical Oceanograpy, Memorial University of Newfoundland, St. John's, NL, Canada
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3
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Zhu S, Weber DK, Separovic F, Sani MA. Expression and purification of the native C-amidated antimicrobial peptide maculatin 1.1. J Pept Sci 2021; 27:e3330. [PMID: 33843136 DOI: 10.1002/psc.3330] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 11/09/2022]
Abstract
Maculatin 1.1 (Mac1) is an antimicrobial peptide (AMP) from an Australian tree frog and exhibits low micromolar activity against Gram-positive bacteria. The antimicrobial properties of Mac1 are linked to its disruption of bacterial lipid membranes, which has been studied extensively by in vitro nuclear magnetic resonance (NMR) spectroscopy and biophysical approaches. Although in vivo NMR has recently proven effective in probing peptide-lipid interplay in live bacterial cells, direct structural characterisation of AMPs has been prohibited by low sensitivity and overwhelming background noise. To overcome this issue, we report a recombinant expression protocol to produce isotopically enriched Mac1. We utilized a double-fusion construct to alleviate toxicity against the Escherichia coli host and generate the native N-free and C-amidated termini Mac1 peptide. The SUMO and intein tags allowed native N-terminus and C-terminal amidation, respectively, to be achieved in a one-pot reaction. The protocol yielded 0.1 mg/L of native, uniformly 15 N-labelled, Mac1, which possessed identical structure and activity to peptide obtained by solid-phase peptide synthesis.
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Affiliation(s)
- Shiying Zhu
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Daniel K Weber
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
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4
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Tkach I, Diederichsen U, Bennati M. Studies of transmembrane peptides by pulse dipolar spectroscopy with semi-rigid TOPP spin labels. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2021; 50:143-157. [PMID: 33640998 PMCID: PMC8071797 DOI: 10.1007/s00249-021-01508-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 01/25/2021] [Accepted: 01/29/2021] [Indexed: 12/01/2022]
Abstract
Electron paramagnetic resonance (EPR)-based pulsed dipolar spectroscopy measures the dipolar interaction between paramagnetic centers that are separated by distances in the range of about 1.5-10 nm. Its application to transmembrane (TM) peptides in combination with modern spin labelling techniques provides a valuable tool to study peptide-to-lipid interactions at a molecular level, which permits access to key parameters characterizing the structural adaptation of model peptides incorporated in natural membranes. In this mini-review, we summarize our approach for distance and orientation measurements in lipid environment using novel semi-rigid TOPP [4-(3,3,5,5-tetramethyl-2,6-dioxo-4-oxylpiperazin-1-yl)-L-phenylglycine] labels specifically designed for incorporation in TM peptides. TOPP labels can report single peak distance distributions with sub-angstrom resolution, thus offering new capabilities for a variety of TM peptide investigations, such as monitoring of various helix conformations or measuring of tilt angles in membranes.
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Affiliation(s)
- Igor Tkach
- Max Planck Institute for Biophysical Chemistry, RG Electron-Spin Resonance Spectroscopy, 37077, Göttingen, Germany.
| | - Ulf Diederichsen
- Department of Organic and Biomolecular Chemistry, University of Göttingen, 37077, Göttingen, Germany
| | - Marina Bennati
- Max Planck Institute for Biophysical Chemistry, RG Electron-Spin Resonance Spectroscopy, 37077, Göttingen, Germany
- Department of Organic and Biomolecular Chemistry, University of Göttingen, 37077, Göttingen, Germany
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5
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Lee TH, Hofferek V, Sani MA, Separovic F, Reid GE, Aguilar MI. The impact of antibacterial peptides on bacterial lipid membranes depends on stage of growth. Faraday Discuss 2021; 232:399-418. [DOI: 10.1039/d0fd00052c] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Impact of maculatin 1.1 on supported lipid bilayers (SLBs) derived from early growth phase (EGP) or stationary growth phase (SGP) E. coli lipid extracts, monitored by atomic force microscopy which images bilayer morphology in real time.
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Affiliation(s)
- Tzong-Hsien Lee
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Vinzenz Hofferek
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, VIC 3010, Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, VIC 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, VIC 3010, Australia
| | - Gavin E. Reid
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, VIC 3010, Australia
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Marie-Isabel Aguilar
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
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6
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Gong H, Sani MA, Hu X, Fa K, Hart JW, Liao M, Hollowell P, Carter J, Clifton LA, Campana M, Li P, King SM, Webster JRP, Maestro A, Zhu S, Separovic F, Waigh TA, Xu H, McBain AJ, Lu JR. How do Self-Assembling Antimicrobial Lipopeptides Kill Bacteria? ACS APPLIED MATERIALS & INTERFACES 2020; 12:55675-55687. [PMID: 33259204 DOI: 10.1021/acsami.0c17222] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Antimicrobial peptides are promising alternatives to traditional antibiotics. A group of self-assembling lipopeptides was formed by attaching an acyl chain to the N-terminus of α-helix-forming peptides with the sequence Cx-G(IIKK)yI-NH2 (CxGy, x = 4-12 and y = 2). CxGy self-assemble into nanofibers above their critical aggregation concentrations (CACs). With increasing x, the CACs decrease and the hydrophobic interactions increase, promoting secondary structure transitions within the nanofibers. Antimicrobial activity, determined by the minimum inhibition concentration (MIC), also decreases with increasing x, but the MICs are significantly smaller than the CACs, suggesting effective bacterial membrane-disrupting power. Unlike conventional antibiotics, both C8G2 and C12G2 can kill Staphylococcus aureus and Escherichia coli after only minutes of exposure under the concentrations studied. C12G2 nanofibers have considerably faster killing dynamics and lower cytotoxicity than their nonaggregated monomers. Antimicrobial activity of peptide aggregates has, to date, been underexploited, and it is found to be a very promising mechanism for peptide design. Detailed evidence for the molecular mechanisms involved is provided, based on superresolution fluorescence microscopy, solid-state nuclear magnetic resonance, atomic force microscopy, neutron scattering/reflectivity, circular dichroism, and Brewster angle microscopy.
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Affiliation(s)
- Haoning Gong
- Biological Physics Laboratory, Department of Physics and Astronomy, Faculty of Science and Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
- Division of Pharmacy and Optometry, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Xuzhi Hu
- Biological Physics Laboratory, Department of Physics and Astronomy, Faculty of Science and Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Ke Fa
- Biological Physics Laboratory, Department of Physics and Astronomy, Faculty of Science and Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Jack William Hart
- Biological Physics Laboratory, Department of Physics and Astronomy, Faculty of Science and Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
- Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Mingrui Liao
- Biological Physics Laboratory, Department of Physics and Astronomy, Faculty of Science and Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
- Division of Pharmacy and Optometry, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Peter Hollowell
- Biological Physics Laboratory, Department of Physics and Astronomy, Faculty of Science and Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Jessica Carter
- Biological Physics Laboratory, Department of Physics and Astronomy, Faculty of Science and Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Luke A Clifton
- ISIS Pulsed Neutron & Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, U.K
| | - Mario Campana
- ISIS Pulsed Neutron & Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, U.K
| | - Peixun Li
- ISIS Pulsed Neutron & Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, U.K
| | - Stephen M King
- ISIS Pulsed Neutron & Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, U.K
| | - John R P Webster
- ISIS Pulsed Neutron & Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, U.K
| | - Armando Maestro
- Institute Laue Langevin, 71 Avenue des Martyrs, CS-20156, Grenoble 38042, France
| | - Shiying Zhu
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Thomas A Waigh
- Biological Physics Laboratory, Department of Physics and Astronomy, Faculty of Science and Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
- Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Hai Xu
- State Key Laboratory of Heavy Oil Processing and the Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Andrew J McBain
- Division of Pharmacy and Optometry, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Jian Ren Lu
- Biological Physics Laboratory, Department of Physics and Astronomy, Faculty of Science and Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
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7
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Strandberg E, Bentz D, Wadhwani P, Ulrich AS. Chiral supramolecular architecture of stable transmembrane pores formed by an α-helical antibiotic peptide in the presence of lyso-lipids. Sci Rep 2020; 10:4710. [PMID: 32170095 PMCID: PMC7070102 DOI: 10.1038/s41598-020-61526-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 02/20/2020] [Indexed: 01/10/2023] Open
Abstract
The amphipathic α-helical antimicrobial peptide MSI-103 (aka KIA21) can form stable transmembrane pores when the bilayer takes on a positive spontaneous curvature, e.g. by the addition of lyso-lipids. Solid-state 31P- and 15N-NMR demonstrated an enrichment of lyso-lipids in these toroidal wormholes. Anionic lyso-lipids provided additional stabilization by electrostatic interactions with the cationic peptides. The remaining lipid matrix did not affect the nature of the pore, as peptides maintained the same orientation independent of lipid charge, and a change in membrane thickness did not considerably affect their tilt angle. Under optimized conditions (i.e. in the presence of lyso-lipids and appropriate bilayer thickness), stable and well-aligned pores could be obtained for solid-state 2H-NMR analysis. These data revealed for the first time the complete 3D alignment of this representative amphiphilic peptide in fluid membranes, which is compatible with either monomeric helices as constituents, or left-handed supercoiled dimers as building blocks from which the overall toroidal wormhole is assembled.
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Affiliation(s)
- Erik Strandberg
- Karlsruhe Institute of Technology (KIT), Institute of Biological Interfaces (IBG-2), POB 3640, 76021, Karlsruhe, Germany
| | - David Bentz
- KIT, Institute of Organic Chemistry, Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
| | - Parvesh Wadhwani
- Karlsruhe Institute of Technology (KIT), Institute of Biological Interfaces (IBG-2), POB 3640, 76021, Karlsruhe, Germany
| | - Anne S Ulrich
- Karlsruhe Institute of Technology (KIT), Institute of Biological Interfaces (IBG-2), POB 3640, 76021, Karlsruhe, Germany.
- KIT, Institute of Organic Chemistry, Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany.
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8
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Karas JA, Keizer DW, Sani MA. Nuclear Magnetic Resonance Study of the Peptide FRANCESSEPAROVIC. Aust J Chem 2020. [DOI: 10.1071/ch19357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
As an eminent ambassador of STEM and renowned NMR spectroscopist, Frances Separovic is an internationally famous name, but could it also be a valuable membrane-active peptide sequence? Her name has been used as an amino acid sequence (FS), successfully synthesised, oxidised, and put into contact with membrane models to investigate any serendipitous activity. The 3D structure of the cyclic FS was determined in dodecylphosphocholine (DPC) micelles by solution NMR spectroscopy. FS displayed a twisted bend separating a helical stretch and an unstructured segment. Using solid-state NMR spectroscopy, the effect of FS on 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dimyristoyl-sn-glycero-3-phosphoserine (DMPS) lipid bilayers was studied. FS did not strongly disturb the neutral membrane surface but likely inserted into their hydrophobic core without a strong effect on the lipid dynamics, while perturbation of the negatively charged membranes remained at the headgroup interface with a strong effect on the lipid dynamics. This study demonstrated that FS is a candidate for discovering potential future therapeutic activities.
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9
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Sani MA, Zhu S, Hofferek V, Separovic F. Nitroxide spin-labeled peptides for DNP-NMR in-cell studies. FASEB J 2019; 33:11021-11027. [PMID: 31284743 DOI: 10.1096/fj.201900931r] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Antimicrobial peptides (AMPs) that target lipid membranes show promise as alternatives to conventional antibiotics. However, the molecular mechanisms of membrane perturbation, as most studies are performed in model systems and in-cell structural studies, have yet to be achieved. Solid-state NMR spectroscopy is a valuable technique to investigate peptide-membrane interactions and to determine the structure of peptides, but the short lifespan of bacteria, especially under magic angle spinning conditions, has not permitted in-cell structural studies. Here, we present the first dynamic nuclear polarization (DNP)-NMR in-cell studies of Escherichia coli bacteria incubated with the AMP maculatin 1.1 (Mac1) in combination with novel nitroxide spin-labeled peptides 2,2,6,6-tetramethylpiperidine-N-oxyl-4-amino-4-carboxylic acid (TOAC)-[F3W]-Mac1 (MacW) and TOAC-TOAC-MacW. The in-cell 13C and 15N signal NMR enhancements, and 1H spin-lattice T1 relaxation times showed that TOAC-MacW and TOAC-TOAC-MacW performed better than the more hydrophilic biradical AMUPol used for DNP studies. Furthermore, the pores formed by the AMP increased the signal enhancements and decreased T1 values of specifically 13C- and 15N-labeled Mac1. This approach has a great potential for determining the first in situ structures of AMPs in bacteria.-Sani, M.-A., Zhu, S., Hofferek, V., Separovic, F. Nitroxide spin-labeled peptides for DNP-NMR in-cell studies.
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Affiliation(s)
- Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Shiying Zhu
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Vinzenz Hofferek
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
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10
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Separovic F. Biophysics & Structural Biology at Synchrotrons BSBS 2019 Biological NMR Session. Biophys Rev 2019; 11:531-532. [PMID: 31123918 PMCID: PMC6682187 DOI: 10.1007/s12551-019-00521-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 04/15/2019] [Indexed: 12/15/2022] Open
Affiliation(s)
- Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia.
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11
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Overall SA, Zhu S, Hanssen E, Separovic F, Sani MA. In Situ Monitoring of Bacteria under Antimicrobial Stress Using 31P Solid-State NMR. Int J Mol Sci 2019; 20:ijms20010181. [PMID: 30621328 PMCID: PMC6337522 DOI: 10.3390/ijms20010181] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/25/2018] [Accepted: 01/01/2019] [Indexed: 11/23/2022] Open
Abstract
In-cell NMR offers great insight into the characterization of the effect of toxins and antimicrobial peptides on intact cells. However, the complexity of intact live cells remains a significant challenge for the analysis of the effect these agents have on different cellular components. Here we show that 31P solid-state NMR can be used to quantitatively characterize the dynamic behaviour of DNA within intact live bacteria. Lipids were also identified and monitored, although 31P dynamic filtering methods indicated a range of dynamic states for phospholipid headgroups. We demonstrate the usefulness of this methodology for monitoring the activity of the antibiotic ampicillin and the antimicrobial peptide (AMP) maculatin 1.1 (Mac1.1) against Gram-negative bacteria. Perturbations in the dynamic behaviour of DNA were observed in treated cells, which indicated additional mechanisms of action for the AMP Mac1.1 not previously reported. This work highlights the value of 31P in-cell solid-state NMR as a tool for assessing the antimicrobial activity of antibiotics and AMPs in bacterial cells.
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Affiliation(s)
- Sarah A Overall
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria 3010, Australia.
- Chemistry & Biochemistry Department, UC Santa Cruz, CA 95064, USA.
| | - Shiying Zhu
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria 3010, Australia.
| | - Eric Hanssen
- Advanced Microscopy Facility and Department of Biochemistry & Molecular Biology, Bio21 Institute, University of Melbourne, Victoria 3010, Australia.
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria 3010, Australia.
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria 3010, Australia.
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12
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Lau QY, Li J, Sani MA, Sinha S, Li Y, Ng FM, Kang C, Bhattacharjya S, Separovic F, Verma C, Chia CSB. Elucidating the bactericidal mechanism of action of the linear antimicrobial tetrapeptide BRBR-NH 2. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1517-1527. [PMID: 29758185 DOI: 10.1016/j.bbamem.2018.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 05/09/2018] [Accepted: 05/09/2018] [Indexed: 12/22/2022]
Abstract
Linear antimicrobial peptides, with their rapid bactericidal mode of action, are well-suited for development as topical antibacterial drugs. We recently designed a synthetic linear 4-residue peptide, BRBR-NH2, with potent bactericidal activity against Staphylococcus aureus (MIC 6.25 μM), the main causative pathogen of human skin infections with an unknown mechanism of action. Herein, we describe a series of experiments conducted to gain further insights into its mechanism of action involving electron microscopy, artificial membrane dye leakage, solution- and solid-state NMR spectroscopy followed by molecular dynamics simulations. Experimental results point towards a SMART (Soft Membranes Adapt and Respond, also Transiently) mechanism of action, suggesting that the peptide can be developed as a topical antibacterial agent for treating drug-resistant Staphylococcus aureus infections.
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Affiliation(s)
- Qiu Ying Lau
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Nanos #03-01, Singapore 138669, Singapore
| | - Jianguo Li
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, Matrix #07-01, Singapore 138671, Singapore; Singapore Eye Research Institute, The Academia, 20 College Road, Singapore 168751, Singapore
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Sheetal Sinha
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore; Interdisciplinary Graduate School, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Yan Li
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Nanos #03-01, Singapore 138669, Singapore
| | - Fui Mee Ng
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Nanos #03-01, Singapore 138669, Singapore
| | - CongBao Kang
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Nanos #03-01, Singapore 138669, Singapore
| | - Surajit Bhattacharjya
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Chandra Verma
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, Matrix #07-01, Singapore 138671, Singapore; School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore 117558, Singapore
| | - Cheng San Brian Chia
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Nanos #03-01, Singapore 138669, Singapore.
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13
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Lee TH, Sani MA, Overall S, Separovic F, Aguilar MI. Effect of phosphatidylcholine bilayer thickness and molecular order on the binding of the antimicrobial peptide maculatin 1.1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:300-309. [DOI: 10.1016/j.bbamem.2017.10.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 09/18/2017] [Accepted: 10/08/2017] [Indexed: 01/01/2023]
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14
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Sani MA, Separovic F. Antimicrobial Peptide Structures: From Model Membranes to Live Cells. Chemistry 2017; 24:286-291. [PMID: 29068097 DOI: 10.1002/chem.201704362] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Indexed: 01/12/2023]
Abstract
The rise in antibiotic resistance has led to a renewed interest in antimicrobial peptides (AMPs) that target membranes. The mode of action of AMPs involves the disruption of the lipid bilayer and leads to growth inhibition and death of the bacteria. However, details at the molecular level of how these peptides kill bacteria and the reasons for the observed differences in selectivity remain unclear. Structural information is crucial for defining the molecular mechanism by which these peptides recognize, self-assemble and interact with a particular lipid membrane. Solid-state NMR is a non-invasive technique that allows the study of the structural details of lipid-peptide and peptide-peptide interactions. Following on from studies of antibiotic and lytic peptides, gramicidin A and melittin, respectively, we investigated maculatin 1.1, an AMP from the skin of Australian tree frogs that acts against Gram-positive bacteria. By using perdeuterated phospholipids and specifically labelled peptides, 2 H, 31 P and {31 P}15 N REDOR solid-state NMR experiments have been used to localize, maculatin 1.1 in neutral and anionic model membranes. However, the structure, location and activity depend on the composition of the model membrane and current advances in solid-state NMR spectroscopy now allow structure determination of AMPs in live bacteria.
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Affiliation(s)
- Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
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15
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Walecka I, Gil-Kulik P, Krzyżanowski A, Czop M, Galkowski D, Karwat J, Chomik P, Świstowska M, Kwaśniewska A, Bogucka-Kocka A, Kocki J. Phenotypic Characterization of Adherent Cells Population CD34+ CD90+ CD105+ Derived from Wharton's Jelly. Med Sci Monit 2017; 23:1886-1895. [PMID: 28422936 PMCID: PMC5405783 DOI: 10.12659/msm.902186] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Background Mesenchymal stromal cells, MSCs, show expression of specific antigens on their surface. The aim of the study is to assess the phenotype of stem cells like isolated from the umbilical cord with respect to the presence of surface antigens CD34, CD90, and CD105 and differences in the expression of surface antigens in cells isolated from freshly sampled material in comparison with the phenotype of cells from in vitro culture. Material/Methods Stem cells collected from the umbilical cord from healthy patients and then cultured in vitro. To assess the phenotype of stem cells, cytometric analysis was carried out. To assess the phenotype of cells we used fluorescently labelled monoclonal antibodies: APC Mouse anti-human CD34, PC5 Mouse anti-human CD90 and PE Mouse anti-human CD105. Results In the case of cells from the umbilical cord and then cultured in vitro for the period of 10–14 days CD34 expression is lower (69,5%) in comparison with the group of cells not cultured. Not cultured cells were demonstrated 37% of cells co-expression of antigens CD34 and CD105, over 21% of CD34/CD90 cells and over 24% of CD105/CD90. Cultured cells group was showed higher percentage of CD90, CD105, CD34/CD105, CD34/CD90, CD105/CD90 in comparison with not cultured cells. Conclusions Our reults suggested that adherent cells population from umbilical cord, demonstrate CD34 expression In vivo. Moreover, the phenotype of MSCs, mainly in the context of CD34 expression, may vary depending on the place of collection of cells and the length of growing the cell culture.
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Affiliation(s)
- Irena Walecka
- Department of Clinical Dermatology, Central Clinical Hospital of the Ministry of the Interior and Administration in Warsaw, Warsaw, Poland
| | - Paulina Gil-Kulik
- Department of Clinical Genetics, Medical University in Lublin, Lublin, Poland
| | - Arkadiusz Krzyżanowski
- Department of Obstetrics and Pathology of Pregnancy, Medical University in Lublin, Lublin, Poland
| | - Marcin Czop
- Department of Clinical Genetics, Medical University in Lublin, Lublin, Poland
| | | | - Jolanta Karwat
- Department of Clinical Genetics, Medical University in Lublin, Lublin, Poland
| | - Piotr Chomik
- Department of Clinical Genetics, Medical University in Lublin, Lublin, Poland
| | | | - Anna Kwaśniewska
- Department of Obstetrics and Pathology of Pregnancy, Medical University in Lublin, Lublin, Poland
| | - Anna Bogucka-Kocka
- Chair and Department of Biology and Genetics, Medical University in Lublin, Lublin, Poland
| | - Janusz Kocki
- Department of Clinical Genetics, Medical University in Lublin, Lublin, Poland
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16
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Zhang R, Mroue KH, Ramamoorthy A. Proton-Based Ultrafast Magic Angle Spinning Solid-State NMR Spectroscopy. Acc Chem Res 2017; 50:1105-1113. [PMID: 28353338 DOI: 10.1021/acs.accounts.7b00082] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Protons are vastly abundant in a wide range of exciting macromolecules and thus can be a powerful probe to investigate the structure and dynamics at atomic resolution using solid-state NMR (ssNMR) spectroscopy. Unfortunately, the high signal sensitivity, afforded by the high natural-abundance and high gyromagnetic ratio of protons, is greatly compromised by severe line broadening due to the very strong 1H-1H dipolar couplings. As a result, protons are rarely used, in spite of the desperate need for enhancing the sensitivity of ssNMR to study a variety of systems that are not amenable for high resolution investigation using other techniques including X-ray crystallography, cryo-electron microscopy, and solution NMR spectroscopy. Thanks to the remarkable improvement in proton spectral resolution afforded by the significant advances in magic-angle-spinning (MAS) probe technology, 1H ssNMR spectroscopy has recently attracted considerable attention in the structural and dynamics studies of various molecular systems. However, it still remains a challenge to obtain narrow 1H spectral lines, especially from proteins, without resorting to deuteration. In this Account, we review recent proton-based ssNMR strategies that have been developed in our laboratory to further improve proton spectral resolution without resorting to chemical deuteration for the purposes of gaining atomistic-level insights into molecular structures of various crystalline solid systems, using small molecules and peptides as illustrative examples. The proton spectral resolution enhancement afforded by the ultrafast MAS frequencies up to 120 kHz is initially discussed, followed by a description of an ensemble of multidimensional NMR pulse sequences, all based on proton detection, that have been developed to obtain in-depth information from dipolar couplings and chemical shift anisotropy (CSA). Simple single channel multidimensional proton NMR experiments could be performed to probe the proximity of protons for structure determination using 1H-1H dipolar couplings and to evaluate the changes in chemical environments as well as the relative orientation to the external magnetic field using proton CSA. Due to the boost in signal sensitivity enabled by proton detection under ultrafast MAS, by virtue of high proton natural abundance and gyromagnetic ratio, proton-detected multidimensional experiments involving low-γ nuclei can now be accomplished within a reasonable time, while the higher dimension also offers additional resolution enhancement. In addition, the application of proton-based ssNMR spectroscopy under ultrafast MAS in various challenging and crystalline systems is also presented. Finally, we briefly discuss the limitations and challenges pertaining to proton-based ssNMR spectroscopy under ultrafast MAS conditions, such as the presence of high-order dipolar couplings, friction-induced sample heating, and limited sample volume. Although there are still a number of challenges that must be circumvented by further developments in radio frequency pulse sequences, MAS probe technology and approaches to prepare NMR-friendly samples, proton-based ssNMR has already gained much popularity in various research domains, especially in proteins where uniform or site-selective deuteration can be relatively easily achieved. In addition, implementation of the recently developed fast data acquisition approaches would also enable further developments in the design and applications of proton-based ultrafast MAS multidimensional ssNMR techniques.
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Affiliation(s)
- Rongchun Zhang
- Biophysics Program and Department
of Chemistry, The University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
| | - Kamal H. Mroue
- Biophysics Program and Department
of Chemistry, The University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
| | - Ayyalusamy Ramamoorthy
- Biophysics Program and Department
of Chemistry, The University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
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17
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Weber DK, Sani MA, Downton MT, Separovic F, Keene FR, Collins JG. Membrane Insertion of a Dinuclear Polypyridylruthenium(II) Complex Revealed by Solid-State NMR and Molecular Dynamics Simulation: Implications for Selective Antibacterial Activity. J Am Chem Soc 2016; 138:15267-15277. [DOI: 10.1021/jacs.6b09996] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Daniel K. Weber
- Computational
Biophysics, IBM Research Australia, Melbourne, VIC 3010, Australia
- School
of Chemistry, Bio21 Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Marc-Antoine Sani
- School
of Chemistry, Bio21 Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Matthew T. Downton
- Computational
Biophysics, IBM Research Australia, Melbourne, VIC 3010, Australia
- School
of Chemistry, Bio21 Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Frances Separovic
- School
of Chemistry, Bio21 Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - F. Richard Keene
- School
of Physical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
- Centre for Biodiscovery & Molecular Development of Therapeutics, James Cook University, Townsville, QLD 4811, Australia
| | - J. Grant Collins
- School
of Physical, Environmental and Mathematical Sciences, University of New South Wales, Australian Defence Force Academy, Canberra, ACT 2600, Australia
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18
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Ravera E, Martelli T, Geiger Y, Fragai M, Goobes G, Luchinat C. Biosilica and bioinspired silica studied by solid-state NMR. Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2016.06.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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