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Kohiyama M, Herrick J, Norris V. Open Questions about the Roles of DnaA, Related Proteins, and Hyperstructure Dynamics in the Cell Cycle. Life (Basel) 2023; 13:1890. [PMID: 37763294 PMCID: PMC10532879 DOI: 10.3390/life13091890] [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: 07/18/2023] [Revised: 08/29/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
The DnaA protein has long been considered to play the key role in the initiation of chromosome replication in modern bacteria. Many questions about this role, however, remain unanswered. Here, we raise these questions within a framework based on the dynamics of hyperstructures, alias large assemblies of molecules and macromolecules that perform a function. In these dynamics, hyperstructures can (1) emit and receive signals or (2) fuse and separate from one another. We ask whether the DnaA-based initiation hyperstructure acts as a logic gate receiving information from the membrane, the chromosome, and metabolism to trigger replication; we try to phrase some of these questions in terms of DNA supercoiling, strand opening, glycolytic enzymes, SeqA, ribonucleotide reductase, the macromolecular synthesis operon, post-translational modifications, and metabolic pools. Finally, we ask whether, underpinning the regulation of the cell cycle, there is a physico-chemical clock inherited from the first protocells, and whether this clock emits a single signal that triggers both chromosome replication and cell division.
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Affiliation(s)
- Masamichi Kohiyama
- Institut Jacques Monod, Université Paris Cité, CNRS, 75013 Paris, France;
| | - John Herrick
- Independent Researcher, 3 rue des Jeûneurs, 75002 Paris, France;
| | - Vic Norris
- CBSA UR 4312, University of Rouen Normandy, University of Caen Normandy, Normandy University, 76000 Rouen, France
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2
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Borcik CG, Versteeg DB, Amani R, Yekefallah M, Khan NH, Wylie BJ. The Lipid Activation Mechanism of a Transmembrane Potassium Channel. J Am Chem Soc 2020; 142:14102-14116. [PMID: 32702990 DOI: 10.1021/jacs.0c01991] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Membrane proteins and lipids coevolved to yield unique coregulatory mechanisms. Inward-rectifier K+ (Kir) channels are often activated by anionic lipids endemic to their native membranes and require accessible water along their K+ conductance pathway. To better understand Kir channel activation, we target multiple mutants of the Kir channel KirBac1.1 via solid-state nuclear magnetic resonance (SSNMR) spectroscopy, potassium efflux assays, and Förster resonance energy transfer (FRET) measurements. In the I131C stability mutant (SM), we observe an open-active channel in the presence of anionic lipids with greater activity upon addition of cardiolipin (CL). The introduction of three R to Q mutations (R49/151/153Q (triple Q mutant, TQ)) renders the protein inactive within the same activating lipid environment. Our SSNMR experiments reveal a stark reduction of lipid-protein interactions in the TQ mutant explaining the dramatic loss of channel activity. Water-edited SSNMR experiments further determined the TQ mutant possesses greater overall solvent exposure in comparison to wild-type but with reduced water accessibility along the ion conduction pathway, consistent with the closed state of the channel. These experiments also suggest water is proximal to the selectivity filter of KirBac1.1 in the open-activated state but that it may not directly enter the selectivity filter. Our findings suggest lipid binding initiates a concerted rotation of the cytoplasmic domain subunits, which is stabilized by multiple intersubunit salt bridges. This action buries ionic side chains away from the bulk water, while allowing water greater access to the K+ conduction pathway. This work highlights universal membrane protein motifs, including lipid-protein interactions, domain rearrangement, and water-mediated diffusion mechanisms.
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Affiliation(s)
- Collin G Borcik
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Derek B Versteeg
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Reza Amani
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Maryam Yekefallah
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Nazmul H Khan
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Benjamin J Wylie
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
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3
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Banigan JR, Leninger M, Her AS, Traaseth NJ. Assessing Interactions Between a Polytopic Membrane Protein and Lipid Bilayers Using Differential Scanning Calorimetry and Solid-State NMR. J Phys Chem B 2018; 122:2314-2322. [PMID: 29457729 DOI: 10.1021/acs.jpcb.8b00479] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It is known that the lipid composition within a cellular membrane can influence membrane protein structure and function. In this Article, we investigated how structural changes to a membrane protein upon substrate binding can impact the lipid bilayer. To carry out this study, we reconstituted the secondary active drug transporter EmrE into a variety of phospholipid bilayers varying in headgroup and chain length and carried out differential scanning calorimetry (DSC) and solid-state NMR experiments. The DSC results revealed a difference in cooperativity of the lipid phase transition for drug-free EmrE protonated at glutamic acid 14 (i.e., proton-loaded form) and the tetraphenylphosphonium (TPP+) bound form of the protein (i.e., drug-loaded form). To complement these findings, we acquired magic-angle-spinning (MAS) spectra in the presence and absence of TPP+ by directly probing the phospholipid headgroup using 31P NMR. These spectra showed a reduction in lipid line widths around the main phase transition for samples where EmrE was bound to TPP+ compared to the drug free form. Finally, we collected oriented solid-state NMR spectra on isotopically enriched EmrE that displayed chemical shift perturbations to both transmembrane and loop residues upon TPP+ binding. All of these results prompt us to propose a mechanism whereby substrate-induced changes to the structural dynamics of EmrE alters the surrounding lipids within the bilayer.
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Affiliation(s)
- James R Banigan
- Department of Chemistry, New York University , New York, New York 10003, United States
| | - Maureen Leninger
- Department of Chemistry, New York University , New York, New York 10003, United States
| | - Ampon Sae Her
- Department of Chemistry, New York University , New York, New York 10003, United States
| | - Nathaniel J Traaseth
- Department of Chemistry, New York University , New York, New York 10003, United States
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4
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Borrell JH, Domènech Ò. Critical Temperature of 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine Monolayers and Its Possible Biological Relevance. J Phys Chem B 2017. [PMID: 28636818 DOI: 10.1021/acs.jpcb.7b04021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Because transmembrane proteins (TMPs) can be obtained with sufficient purity for X-ray diffraction studies more frequently than decades ago, their mechanisms of action may now be elucidated. One of the pending issues is the actual interplay between transmembrane proteins and membrane lipids. There is strong evidence of the involvement of specific lipids with some membrane proteins, such as the potassium crystallographically sited activation channel (KcsA) of Streptomyces lividans and the secondary transporter of lactose LacY of Escherichia coli, the activities of which are associated with the presence of anionic phospholipids such as the phosphatidylglycerol (PG) and phosphatidyethanolamine (PE), respectively. Other proteins such as the large conductance mechanosensitive channel (MscL) of E. coli seem to depend on the adaptation of specific phospholipids to the irregular surface of the integral membrane protein. In this work we investigated the lateral compressibility of two homoacid phosphatidylethanolamines (one with both acyl chains unsaturated (DOPE), the other with the acyl chains saturated (DPPE)) and the heteroacid phosphatidyletanolamine (POPE) and their mixtures with POPG. The liquid expanded (LE) to liquid condensed (LC) transition was observed in POPE at a temperature below its critical temperature (Tc = 36 °C). Because Tc lies below the physiological temperature, the occurrence of this phase transition may have something to do with the functioning of LacY. This magnitude is discussed within the context of the experiments carried out at temperatures below the Tc of POPE at which the activity of Lac Y and other TMPs are frequently studied.
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Affiliation(s)
- Jordi H Borrell
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy and Food Sciences and ‡Institute of Nanoscience and Nanotechnology (IN2UB), University of Barcelona (UB) , E-08028 Barcelona, Spain
| | - Òscar Domènech
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy and Food Sciences and ‡Institute of Nanoscience and Nanotechnology (IN2UB), University of Barcelona (UB) , E-08028 Barcelona, Spain
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5
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Shigeta A, Ito S, Inoue K, Okitsu T, Wada A, Kandori H, Kawamura I. Solid-State Nuclear Magnetic Resonance Structural Study of the Retinal-Binding Pocket in Sodium Ion Pump Rhodopsin. Biochemistry 2017; 56:543-550. [PMID: 28040890 DOI: 10.1021/acs.biochem.6b00999] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The recently identified Krokinobacter rhodopsin 2 (KR2) functions as a light-driven sodium ion pump. The structure of the retinal-binding pocket of KR2 offers important insights into the mechanisms of KR2, which has motif of Asn112, Asp116, and Gln123 (NDQ) that is common among sodium ion pump rhodopsins but is unique among other microbial rhodopsins. Here we present solid-state nuclear magnetic resonance (NMR) characterization of retinal and functionally important residues in the vicinity of retinal in the ground state. We assigned chemical shifts of retinal C14 and C20 atoms, and Tyr218Cζ, Lys255Cε, and the protonated Schiff base of KR2 in lipid environments at acidic and neutral pH. 15N NMR signals of the protonated Schiff base showed a twist around the N-Cε bond under neutral conditions, compared with other microbial rhodopsins. These data indicated that the location of the counterion Asp116 is one helical pitch toward the cytoplasmic side. In acidic environments, the 15N Schiff base signal was shifted to a lower field, indicating that protonation of Asp116 induces reorientation during interactions between the Schiff base and Asp116. In addition, the Tyr218 residue in the vicinity of retinal formed a weak hydrogen bond with Asp251, a temporary Na+-binding site during the photocycle. These features may indicate unique mechanisms of sodium ion pumps.
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Affiliation(s)
- Arisu Shigeta
- Graduate School of Engineering, Yokohama National University , Hodogaya-ku, Yokohama 240-8501, Japan
| | - Shota Ito
- Department of Frontier Materials, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan
| | - Keiichi Inoue
- Department of Frontier Materials, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan.,OptoBioTechnology Research Center, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan.,PRESTO, Japan Science and Technology Agency (JST) , 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
| | - Takashi Okitsu
- Department of Organic Chemistry for Life Science, Kobe Pharmaceutical University , Higashinada-ku, Kobe 658-8558, Japan
| | - Akimori Wada
- Department of Organic Chemistry for Life Science, Kobe Pharmaceutical University , Higashinada-ku, Kobe 658-8558, Japan
| | - Hideki Kandori
- Department of Frontier Materials, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan.,OptoBioTechnology Research Center, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan
| | - Izuru Kawamura
- Graduate School of Engineering, Yokohama National University , Hodogaya-ku, Yokohama 240-8501, Japan
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6
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Mehmood S, Corradi V, Choudhury HG, Hussain R, Becker P, Axford D, Zirah S, Rebuffat S, Tieleman DP, Robinson CV, Beis K. Structural and Functional Basis for Lipid Synergy on the Activity of the Antibacterial Peptide ABC Transporter McjD. J Biol Chem 2016; 291:21656-21668. [PMID: 27555327 DOI: 10.1074/jbc.m116.732107] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 08/08/2016] [Indexed: 11/06/2022] Open
Abstract
The lipid bilayer is a dynamic environment that consists of a mixture of lipids with different properties that regulate the function of membrane proteins; these lipids are either annular, masking the protein hydrophobic surface, or specific lipids, essential for protein function. In this study, using tandem mass spectrometry, we have identified specific lipids associated with the Escherichia coli ABC transporter McjD, which translocates the antibacterial peptide MccJ25. Using non-denaturing mass spectrometry, we show that McjD in complex with MccJ25 survives the gas phase. Partial delipidation of McjD resulted in reduced ATPase activity and thermostability as shown by circular dichroism, both of which could be restored upon addition of defined E. coli lipids. We have resolved a phosphatidylglycerol lipid associated with McjD at 3.4 Å resolution, whereas molecular dynamic simulations carried out in different lipid environments assessed the binding of specific lipids to McjD. Combined, our data show a synergistic effect of zwitterionic and negatively charged lipids on the activity of McjD; the zwitterionic lipids provide structural stability to McjD, whereas the negatively charged lipids are essential for its function.
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Affiliation(s)
- Shahid Mehmood
- From the Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Valentina Corradi
- the Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Hassanul G Choudhury
- the Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom.,the Membrane Protein Lab.,the Rutherford Appleton Laboratory, Research Complex at Harwell, Oxfordshire OX11 0DE, United Kingdom, and
| | - Rohanah Hussain
- Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire, OX11 0DE, United Kingdom
| | - Patrick Becker
- the Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom.,the Membrane Protein Lab.,the Rutherford Appleton Laboratory, Research Complex at Harwell, Oxfordshire OX11 0DE, United Kingdom, and
| | - Danny Axford
- Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire, OX11 0DE, United Kingdom
| | - Severine Zirah
- the Communication Molecules and Adaptation of Microorganisms Laboratory (MCAM, UMR 7245 CNRS-MNHN), Sorbonne Universités, Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, CP 54, 57 Rue Cuvier, 75005 Paris, France
| | - Sylvie Rebuffat
- the Communication Molecules and Adaptation of Microorganisms Laboratory (MCAM, UMR 7245 CNRS-MNHN), Sorbonne Universités, Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, CP 54, 57 Rue Cuvier, 75005 Paris, France
| | - D Peter Tieleman
- the Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Carol V Robinson
- From the Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom,
| | - Konstantinos Beis
- the Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom, .,the Membrane Protein Lab.,the Rutherford Appleton Laboratory, Research Complex at Harwell, Oxfordshire OX11 0DE, United Kingdom, and
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7
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Membrane interactions of proline-rich antimicrobial peptide, Chex1-Arg20, multimers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1236-43. [PMID: 26926423 DOI: 10.1016/j.bbamem.2016.02.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 02/15/2016] [Accepted: 02/24/2016] [Indexed: 01/10/2023]
Abstract
The increasing prevalence of antibiotic-resistant pathogens requires the development of new antibiotics. Proline-rich antimicrobial peptides (PrAMPs), including native apidaecins, Bac7, and oncocins or designed A3APO, show multi-modal actions against pathogens together with immunostimulatory activities. The interactions of the designed PrAMP, Chex1-Arg20, and its dimeric and tetrameric oligomers with different model membranes were investigated by circular dichroism spectroscopy, dynamic light scattering, zeta potential, differential scanning calorimetry, and dye leakage. Chex1-Arg20 oligomers showed stronger affinity and preferential binding to negatively charged phospholipid bilayers and led to lipid aggregation and neutralization. Fluorescence microscopy of negatively charged giant unilamellar vesicles with AlexFluor-647-labeled Chex1-Arg20 dimers and tetramers displayed aggregation at a peptide/lipid low ratio of 1:200 and at higher peptide concentrations (1:100/1:50) for Chex1-Arg20 monomer. Such interactions, aggregation, and neutralization of PrAMP oligomers additionally showed the importance of interactions of PrAMPs with negatively charged membranes.
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8
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Ciprofloxacin Metalloantibiotic: An Effective Antibiotic with an Influx Route Strongly Dependent on Lipid Interaction? J Membr Biol 2014; 248:125-36. [DOI: 10.1007/s00232-014-9749-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 10/29/2014] [Indexed: 12/01/2022]
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9
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Suárez-Germà C, Morros A, Montero M, Hernández-Borrell J, Domènech Ò. Combined force spectroscopy, AFM and calorimetric studies to reveal the nanostructural organization of biomimetic membranes. Chem Phys Lipids 2014; 183:208-17. [DOI: 10.1016/j.chemphyslip.2014.07.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 07/14/2014] [Accepted: 07/28/2014] [Indexed: 01/12/2023]
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10
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Suárez-Germà C, Hernández-Borrell J, Prieto M, Loura LMS. Modeling FRET to investigate the selectivity of lactose permease ofEscherichia colifor lipids. Mol Membr Biol 2014; 31:120-30. [DOI: 10.3109/09687688.2014.915351] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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11
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Suárez-Germà C, Domènech Ò, Montero MT, Hernández-Borrell J. Effect of lactose permease presence on the structure and nanomechanics of two-component supported lipid bilayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:842-52. [DOI: 10.1016/j.bbamem.2013.11.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 11/20/2013] [Accepted: 11/22/2013] [Indexed: 01/24/2023]
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12
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Suárez-Germà C, Loura LMS, Prieto M, Domènech Ò, Campanera JM, Montero MT, Hernández-Borrell J. Phospholipid–Lactose Permease Interaction As Reported by a Head-Labeled Pyrene Phosphatidylethanolamine: A FRET Study. J Phys Chem B 2013; 117:6741-8. [DOI: 10.1021/jp402152n] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Luís M. S. Loura
- Faculdade de Farmácia, Universidade de Coimbra, Azinhaga de Santa Comba, 3000-548
Coimbra, Portugal
- Centro de Química de Coimbra, 3004-535 Coimbra, Portugal
| | - Manuel Prieto
- Centro de Química-Física
Molecular and Institute of Nanoscience and Nanotechnology (IN), Instituto
Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa, Portugal
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13
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Suárez-Germà C, Loura LMS, Domènech O, Montero MT, Vázquez-Ibar JL, Hernández-Borrell J. Phosphatidylethanolamine-lactose permease interaction: a comparative study based on FRET. J Phys Chem B 2012; 116:14023-8. [PMID: 23137163 DOI: 10.1021/jp309726v] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this work we have investigated the selectivity of lactose permease (LacY) of Escherichia coli (E. coli) for its surrounding phospholipids when reconstituted in binary mixtures of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), 1,2-Palmitoyl-sn-glycero-3-phosphoethanolamine (DPPE), or 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) with 1-palmitoyl-2-oleoyl-sn-glycero-3-(phospho-rac-(1-glycerol)) (POPG). Förster resonance energy transfer (FRET) measurements have been performed to investigate the selectivity between a single tryptophan mutant of LacY used as donor (D), and two analogues of POPE and POPG labeled with pyrene in the acyl chains (Pyr-PE and Pyr-PG) used as acceptors. As a difference from previous works, now the donor has been single-W151/C154G/D68C LacY. It has been reported that the replacement of the aspartic acid in position 68 by cysteine inhibits active transport in LacY. The objectives of this work were to elucidate the phospholipid composition of the annular region of this mutant and to determine whether the mutation performed, D68C, induced changes in the protein-lipid selectivity. FRET efficiencies for Pyr-PE were always higher than for Pyr-PG. The values of the probability of each site in the annular ring being occupied by a label (μ) were similar at the studied temperatures (24 °C and 37 °C), suggesting that the lipid environment is not significantly affected when increasing the temperature. By comparing the results with those obtained for single-W151/C154G LacY, we observe that the mutation in the 68 residue indeed changes the selectivity of the protein for the phospholipids. This might be probably due to a change in the conformational dynamics of LacY.
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Affiliation(s)
- Carme Suárez-Germà
- Departament de Fisicoquímica, Facultat de Farmàcia, Universitat de Barcelona, Spain
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14
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Suárez-Germà C, Loura LMS, Prieto M, Domènech Ò, Montero MT, Rodríguez-Banqueri A, Vázquez-Ibar JL, Hernández-Borrell J. Membrane Protein–Lipid Selectivity: Enhancing Sensitivity for Modeling FRET Data. J Phys Chem B 2012; 116:2438-45. [DOI: 10.1021/jp2105665] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Luís M. S. Loura
- Faculdade de Farmácia, Universidade de Coimbra, Azinhaga de Santa Comba, 3000-548
Coimbra, Portugal and Centro de Química de Coimbra, 3004-535 Coimbra, Portugal
| | - Manuel Prieto
- Centro de Química-Física Molecular and IN, IST, 1049-001, Lisboa, Portugal
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15
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Suárez-Germà C, Montero M, Ignés-Mullol J, Hernández-Borrell J, Domènech Ò. Acyl Chain Differences in Phosphatidylethanolamine Determine Domain Formation and LacY Distribution in Biomimetic Model Membranes. J Phys Chem B 2011; 115:12778-84. [DOI: 10.1021/jp206369k] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Carme Suárez-Germà
- Department of Physical Chemistry, Faculty of Pharmacy, and ‡Faculty of Chemistry, IN2UB, University of Barcelona, E-08028-Barcelona, Spain
| | - M.Teresa Montero
- Department of Physical Chemistry, Faculty of Pharmacy, and ‡Faculty of Chemistry, IN2UB, University of Barcelona, E-08028-Barcelona, Spain
| | - Jordi Ignés-Mullol
- Department of Physical Chemistry, Faculty of Pharmacy, and ‡Faculty of Chemistry, IN2UB, University of Barcelona, E-08028-Barcelona, Spain
| | - Jordi Hernández-Borrell
- Department of Physical Chemistry, Faculty of Pharmacy, and ‡Faculty of Chemistry, IN2UB, University of Barcelona, E-08028-Barcelona, Spain
| | - Òscar Domènech
- Department of Physical Chemistry, Faculty of Pharmacy, and ‡Faculty of Chemistry, IN2UB, University of Barcelona, E-08028-Barcelona, Spain
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16
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Cheng JTJ, Hale JD, Elliott M, Hancock REW, Straus SK. The importance of bacterial membrane composition in the structure and function of aurein 2.2 and selected variants. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1808:622-33. [PMID: 21144817 DOI: 10.1016/j.bbamem.2010.11.025] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 10/08/2010] [Accepted: 11/20/2010] [Indexed: 11/29/2022]
Abstract
For cationic antimicrobial peptides to become useful therapeutic agents, it is important to understand their mechanism of action. To obtain high resolution data, this involves studying the structure and membrane interaction of these peptides in tractable model bacterial membranes rather than directly utilizing more complex bacterial surfaces. A number of lipid mixtures have been used as bacterial mimetics, including a range of lipid headgroups, and different ratios of neutral to negatively charged headgroups. Here we examine how the structure and membrane interaction of aurein 2.2 and some of its variants depend on the choice of lipids, and how these models correlate with activity data in intact bacteria (MICs, membrane depolarization). Specifically, we investigated the structure and membrane interaction of aurein 2.2 and aurein 2.3 in 1:1 cardiolipin/1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (CL/POPG) (mol/mol), as an alternative to 1:1 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine(POPC)/POPG and a potential model for Gram positive bacteria such as S. aureus. The structure and membrane interaction of aurein 2.2, aurein 2.3, and five variants of aurein 2.2 were also investigated in 1:1 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE)/POPG (mol/mol) lipids as a possible model for other Gram positive bacteria, such as Bacillus cereus. Solution circular dichroism (CD) results demonstrated that the aurein peptides adopted α-helical structure in all lipid membranes examined, but demonstrated a greater helical content in the presence of POPE/POPG membranes. Oriented CD and ³¹P NMR results showed that the aurein peptides had similar membrane insertion profiles and headgroup disordering effects on POPC/POPG and CL/POPG bilayers, but demonstrated reduced membrane insertion and decreased headgroup disordering on mixing with POPE/POPG bilayers at low peptide concentrations. Since the aurein peptides behaved very differently in POPE/POPG membrane, minimal inhibitory concentrations (MICs) of the aurein peptides in B. cereus strain C737 were determined. The MIC results indicated that all aurein peptides are significantly less active against B. cereus than against S. aureus and S. epidermidis. Overall, the data suggest that it is important to use a relevant model for bacterial membranes to gain insight into the mode of action of a given antimicrobial peptide in specific bacteria.
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Affiliation(s)
- John T J Cheng
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T1Z1, Canada
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17
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Lactose permease lipid selectivity using Förster resonance energy transfer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1707-13. [DOI: 10.1016/j.bbamem.2010.05.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 05/09/2010] [Accepted: 05/12/2010] [Indexed: 11/23/2022]
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Lopes S, Neves CS, Eaton P, Gameiro P. Cardiolipin, a key component to mimic the E. coli bacterial membrane in model systems revealed by dynamic light scattering and steady-state fluorescence anisotropy. Anal Bioanal Chem 2010; 398:1357-66. [PMID: 20680614 DOI: 10.1007/s00216-010-4028-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 07/11/2010] [Accepted: 07/12/2010] [Indexed: 12/01/2022]
Abstract
The phase transition temperatures of several lipidic systems were determined using two different techniques: dynamic light scattering (DLS) and steady-state fluorescence anisotropy, using two fluorescent probes that report different membrane regions (TMA-DPH and DPH). Atomic force microscopy (AFM) was used as a complementary technique to characterize different lipid model systems under study. The systems were chosen due to the increased interest in bacterial membrane studies due to the problem of antibiotic drug resistance. The simpler models studied comprised of mixtures of POPE and POPG lipids, which form a commonly used model system for Escherichia coli membranes. Given the important role of cardiolipin (CL) in natural membranes, a ternary model system, POPE/POPG/CL, was then considered. The results obtained in these mimetic systems were compared with those obtained for the natural systems E. coli polar and total lipid extract. DLS and fluorescence anisotropy are not commonly used to study lipid phase transitions, but it was shown that they can give useful information about the thermotropic behaviors of model systems for bacterial membranes. These two techniques provided very similar results, validating their use as methods to measure phase transitions in lipid model systems. The temperature transitions obtained from these two very different techniques and the AFM results clearly show that cardiolipin is a fundamental component to mimic bacteria membranes. The results suggest that the less commonly used ternary system is a considerably better mimic for natural E. coli membranes than binary lipid mixture.
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Affiliation(s)
- S Lopes
- Requimte, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal
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Picas L, Carretero-Genevrier A, Montero MT, Vázquez-Ibar J, Seantier B, Milhiet PE, Hernández-Borrell J. Preferential insertion of lactose permease in phospholipid domains: AFM observations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1014-9. [DOI: 10.1016/j.bbamem.2010.01.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 01/01/2010] [Accepted: 01/11/2010] [Indexed: 11/29/2022]
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