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Moutoussamy E, Khan HM, Roberts MF, Gershenson A, Chipot C, Reuter N. Standard Binding Free Energy and Membrane Desorption Mechanism for a Phospholipase C. J Chem Inf Model 2022; 62:6602-6613. [PMID: 35343689 PMCID: PMC9795555 DOI: 10.1021/acs.jcim.1c01543] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Peripheral membrane proteins (PMPs) bind temporarily to cellular membranes and play important roles in signaling, lipid metabolism, and membrane trafficking. Obtaining accurate membrane-PMP affinities using experimental techniques is more challenging than for protein-ligand affinities in an aqueous solution. At the theoretical level, calculation of the standard protein-membrane binding free energy using molecular dynamics simulations remains a daunting challenge owing to the size of the biological objects at play, the slow lipid diffusion, and the large variation in configurational entropy that accompanies the binding process. To overcome these challenges, we used a computational framework relying on a series of potential-of-mean-force (PMF) calculations including a set of geometrical restraints on collective variables. This methodology allowed us to determine the standard binding free energy of a PMP to a phospholipid bilayer using an all-atom force field. Bacillus thuringiensis phosphatidylinositol-specific phospholipase C (BtPI-PLC) was chosen due to its importance as a virulence factor and owing to the host of experimental affinity data available. We computed a standard binding free energy of -8.2 ± 1.4 kcal/mol in reasonable agreement with the reported experimental values (-6.6 ± 0.2 kcal/mol). In light of the 2.3-μs separation PMF calculation, we investigated the mechanism whereby BtPI-PLC disengages from interactions with the lipid bilayer during separation. We describe how a short amphipathic helix engages in transitory interactions to ease the passage of its hydrophobes through the interfacial region upon desorption from the bilayer.
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Affiliation(s)
- Emmanuel
E. Moutoussamy
- Department
of Biological Sciences, University of Bergen, N-5020 Bergen, Norway,Computational
Biology Unit, Department of Informatics, University of Bergen, N-5020 Bergen, Norway
| | - Hanif M. Khan
- Department
of Biological Sciences, University of Bergen, N-5020 Bergen, Norway,Computational
Biology Unit, Department of Informatics, University of Bergen, N-5020 Bergen, Norway
| | - Mary F. Roberts
- Department
of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Anne Gershenson
- Department
of Biochemistry and Molecular Biology, University
of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Christophe Chipot
- Laboratoire
International Associé Centre National de la Recherche Scientifique
et University of Illinois at Urbana−Champaign, Unité
Mixte de Recherche n 7019, Université
de Lorraine, BP 70239, 54506 Vandœuvre-lès-Nancy cedex, France,Department
of Physics, University of Illinois, Urbana, Illinois 61801, United States
| | - Nathalie Reuter
- Computational
Biology Unit, Department of Informatics, University of Bergen, N-5020 Bergen, Norway,Department
of Chemistry, University of Bergen, N-5020 Bergen, Norway,
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2
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Roberts MF, Gershenson A, Reuter N. Phosphatidylcholine Cation—Tyrosine π Complexes: Motifs for Membrane Binding by a Bacterial Phospholipase C. Molecules 2022; 27:molecules27196184. [PMID: 36234717 PMCID: PMC9572076 DOI: 10.3390/molecules27196184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 09/14/2022] [Accepted: 09/15/2022] [Indexed: 10/27/2022] Open
Abstract
Phosphatidylinositol-specific phospholipase C (PI-PLC) enzymes are a virulence factor in many Gram-positive organisms. The specific activity of the Bacillus thuringiensis PI-PLC is significantly increased by adding phosphatidylcholine (PC) to vesicles composed of the substrate phosphatidylinositol, in part because the inclusion of PC reduces the apparent Kd for the vesicle binding by as much as 1000-fold when comparing PC-rich vesicles to PI vesicles. This review summarizes (i) the experimental work that localized a site on BtPI-PLC where PC is bound as a PC choline cation—Tyr-π complex and (ii) the computational work (including all-atom molecular dynamics simulations) that refined the original complex and found a second persistent PC cation—Tyr-π complex. Both complexes are critical for vesicle binding. These results have led to a model for PC functioning as an allosteric effector of the enzyme by altering the protein dynamics and stabilizing an ‘open’ active site conformation.
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Affiliation(s)
- Mary F. Roberts
- Department of Chemistry, Boston College, Chestnut Hill, MA 02467, USA
- Correspondence: ; Tel.: +1-617-460-5194
| | - Anne Gershenson
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Nathalie Reuter
- Computational Biology Unit, Department of Informatics and Chemistry, University of Bergen, 5020 Bergen, Norway
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3
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Muller MP, Jiang T, Sun C, Lihan M, Pant S, Mahinthichaichan P, Trifan A, Tajkhorshid E. Characterization of Lipid-Protein Interactions and Lipid-Mediated Modulation of Membrane Protein Function through Molecular Simulation. Chem Rev 2019; 119:6086-6161. [PMID: 30978005 PMCID: PMC6506392 DOI: 10.1021/acs.chemrev.8b00608] [Citation(s) in RCA: 133] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The cellular membrane constitutes one of the most fundamental compartments of a living cell, where key processes such as selective transport of material and exchange of information between the cell and its environment are mediated by proteins that are closely associated with the membrane. The heterogeneity of lipid composition of biological membranes and the effect of lipid molecules on the structure, dynamics, and function of membrane proteins are now widely recognized. Characterization of these functionally important lipid-protein interactions with experimental techniques is however still prohibitively challenging. Molecular dynamics (MD) simulations offer a powerful complementary approach with sufficient temporal and spatial resolutions to gain atomic-level structural information and energetics on lipid-protein interactions. In this review, we aim to provide a broad survey of MD simulations focusing on exploring lipid-protein interactions and characterizing lipid-modulated protein structure and dynamics that have been successful in providing novel insight into the mechanism of membrane protein function.
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Affiliation(s)
- Melanie P. Muller
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- College of Medicine
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Tao Jiang
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Chang Sun
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Muyun Lihan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Shashank Pant
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Paween Mahinthichaichan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Anda Trifan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- College of Medicine
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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4
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Roberts MF, Khan HM, Goldstein R, Reuter N, Gershenson A. Search and Subvert: Minimalist Bacterial Phosphatidylinositol-Specific Phospholipase C Enzymes. Chem Rev 2018; 118:8435-8473. [DOI: 10.1021/acs.chemrev.8b00208] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Mary F. Roberts
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | | | - Rebecca Goldstein
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | | | - Anne Gershenson
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
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5
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Navaratnarajah P, Gershenson A, Ross EM. The binding of activated Gα q to phospholipase C-β exhibits anomalous affinity. J Biol Chem 2017; 292:16787-16801. [PMID: 28842497 DOI: 10.1074/jbc.m117.809673] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 08/22/2017] [Indexed: 01/01/2023] Open
Abstract
Upon activation by the Gq family of Gα subunits, Gβγ subunits, and some Rho family GTPases, phospholipase C-β (PLC-β) isoforms hydrolyze phosphatidylinositol 4,5-bisphosphate to the second messengers inositol 1,4,5-trisphosphate and diacylglycerol. PLC-β isoforms also function as GTPase-activating proteins, potentiating Gq deactivation. To elucidate the mechanism of this mutual regulation, we measured the thermodynamics and kinetics of PLC-β3 binding to Gαq FRET and fluorescence correlation spectroscopy, two physically distinct methods, both yielded Kd values of about 200 nm for PLC-β3-Gαq binding. This Kd is 50-100 times greater than the EC50 for Gαq-mediated PLC-β3 activation and for the Gαq GTPase-activating protein activity of PLC-β. The measured Kd was not altered either by the presence of phospholipid vesicles, phosphatidylinositol 4,5-bisphosphate and Ca2+, or by the identity of the fluorescent labels. FRET-based kinetic measurements were also consistent with a Kd of 200 nm We determined that PLC-β3 hysteresis, whereby PLC-β3 remains active for some time following either Gαq-PLC-β3 dissociation or PLC-β3-potentiated Gαq deactivation, is not sufficient to explain the observed discrepancy between EC50 and Kd These results indicate that the mechanism by which Gαq and PLC-β3 mutually regulate each other is far more complex than a simple, two-state allosteric model and instead is probably kinetically determined.
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Affiliation(s)
- Punya Navaratnarajah
- From the Department of Pharmacology and Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9041 and
| | - Anne Gershenson
- the Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003-9292
| | - Elliott M Ross
- From the Department of Pharmacology and Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9041 and
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6
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Khan HM, He T, Fuglebakk E, Grauffel C, Yang B, Roberts MF, Gershenson A, Reuter N. A Role for Weak Electrostatic Interactions in Peripheral Membrane Protein Binding. Biophys J 2016; 110:1367-78. [PMID: 27028646 PMCID: PMC4816757 DOI: 10.1016/j.bpj.2016.02.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 01/08/2016] [Accepted: 02/02/2016] [Indexed: 12/01/2022] Open
Abstract
Bacillus thuringiensis phosphatidylinositol-specific phospholipase C (BtPI-PLC) is a secreted virulence factor that binds specifically to phosphatidylcholine (PC) bilayers containing negatively charged phospholipids. BtPI-PLC carries a negative net charge and its interfacial binding site has no obvious cluster of basic residues. Continuum electrostatic calculations show that, as expected, nonspecific electrostatic interactions between BtPI-PLC and membranes vary as a function of the fraction of anionic lipids present in the bilayers. Yet they are strikingly weak, with a calculated ΔGel below 1 kcal/mol, largely due to a single lysine (K44). When K44 is mutated to alanine, the equilibrium dissociation constant for small unilamellar vesicles increases more than 50 times (∼2.4 kcal/mol), suggesting that interactions between K44 and lipids are not merely electrostatic. Comparisons of molecular-dynamics simulations performed using different lipid compositions reveal that the bilayer composition does not affect either hydrogen bonds or hydrophobic contacts between the protein interfacial binding site and bilayers. However, the occupancies of cation-π interactions between PC choline headgroups and protein tyrosines vary as a function of PC content. The overall contribution of basic residues to binding affinity is also context dependent and cannot be approximated by a rule-of-thumb value because these residues can contribute to both nonspecific electrostatic and short-range protein-lipid interactions. Additionally, statistics on the distribution of basic amino acids in a data set of membrane-binding domains reveal that weak electrostatics, as observed for BtPI-PLC, might be a less unusual mechanism for peripheral membrane binding than is generally thought.
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Affiliation(s)
- Hanif M Khan
- Department of Molecular Biology, University of Bergen, Bergen, Norway; Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway
| | - Tao He
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts
| | - Edvin Fuglebakk
- Department of Molecular Biology, University of Bergen, Bergen, Norway; Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway
| | - Cédric Grauffel
- Department of Molecular Biology, University of Bergen, Bergen, Norway; Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway
| | - Boqian Yang
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts; Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts
| | - Mary F Roberts
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts
| | - Anne Gershenson
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts
| | - Nathalie Reuter
- Department of Molecular Biology, University of Bergen, Bergen, Norway; Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway.
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7
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Huang Q, Gershenson A, Roberts MF. Recombinant broad-range phospholipase C from Listeria monocytogenes exhibits optimal activity at acidic pH. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:697-705. [PMID: 26976751 DOI: 10.1016/j.bbapap.2016.03.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/08/2016] [Accepted: 03/10/2016] [Indexed: 10/22/2022]
Abstract
The broad-range phospholipase C (PLC) from Listeria monocytogenes has been expressed using an intein expression system and characterized. This zinc metalloenzyme, similar to the homologous enzyme from Bacillus cereus, targets a wide range of lipid substrates. With monomeric substrates, the length of the hydrophobic acyl chain has significant impact on enzyme efficiency by affecting substrate affinity (Km). Based on a homology model of the enzyme to the B. cereus protein, several active site residue mutations were generated. While this PLC shares many of the mechanistic characteristics of the B. cereus PLC, a major difference is that the L. monocytogenes enzyme displays an acidic pH optimum regardless of substrate status (monomer, micelle, or vesicle). This unusual behavior might be advantageous for its role in the pathogenicity of L. monocytogenes.
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Affiliation(s)
- Qiongying Huang
- Department of Chemistry, Boston College, Chestnut Hill, MA, United States.
| | - Anne Gershenson
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA, United States
| | - Mary F Roberts
- Department of Chemistry, Boston College, Chestnut Hill, MA, United States
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8
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He T, Gershenson A, Eyles SJ, Lee YJ, Liu WR, Wang J, Gao J, Roberts MF. Fluorinated Aromatic Amino Acids Distinguish Cation-π Interactions from Membrane Insertion. J Biol Chem 2015; 290:19334-42. [PMID: 26092728 DOI: 10.1074/jbc.m115.668343] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Indexed: 01/02/2023] Open
Abstract
Cation-π interactions, where protein aromatic residues supply π systems while a positive-charged portion of phospholipid head groups are the cations, have been suggested as important binding modes for peripheral membrane proteins. However, aromatic amino acids can also insert into membranes and hydrophobically interact with lipid tails. Heretofore there has been no facile way to differentiate these two types of interactions. We show that specific incorporation of fluorinated amino acids into proteins can experimentally distinguish cation-π interactions from membrane insertion of the aromatic side chains. Fluorinated aromatic amino acids destabilize the cation-π interactions by altering electrostatics of the aromatic ring, whereas their increased hydrophobicity enhances membrane insertion. Incorporation of pentafluorophenylalanine or difluorotyrosine into a Staphylococcus aureus phosphatidylinositol-specific phospholipase C variant engineered to contain a specific PC-binding site demonstrates the effectiveness of this methodology. Applying this methodology to the plethora of tyrosine residues in Bacillus thuringiensis phosphatidylinositol-specific phospholipase C definitively identifies those involved in cation-π interactions with phosphatidylcholine. This powerful method can easily be used to determine the roles of aromatic residues in other peripheral membrane proteins and in integral membrane proteins.
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Affiliation(s)
- Tao He
- From the Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467
| | - Anne Gershenson
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Stephen J Eyles
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Yan-Jiun Lee
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, and
| | - Wenshe R Liu
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, and
| | - Jiangyun Wang
- Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing 100101, China
| | - Jianmin Gao
- From the Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467
| | - Mary F Roberts
- From the Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467,
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9
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Celandroni F, Salvetti S, Senesi S, Ghelardi E. Bacillus thuringiensis membrane-damaging toxins acting on mammalian cells. FEMS Microbiol Lett 2014; 361:95-103. [PMID: 25283838 DOI: 10.1111/1574-6968.12615] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/26/2014] [Accepted: 09/29/2014] [Indexed: 01/20/2023] Open
Abstract
Bacillus thuringiensis is widely used as a biopesticide in forestry and agriculture, being able to produce potent species-specific insecticidal toxins and considered nonpathogenic to other animals. More recently, however, repeated observations are documenting the association of this microorganism with various infectious diseases in humans, such as food-poisoning-associated diarrheas, periodontitis, bacteremia, as well as ocular, burn, and wound infections. Similar to B. cereus, B. thuringiensis produces an array of virulence factors acting against mammalian cells, such as phosphatidylcholine- and phosphatidylinositol-specific phospholipase C (PC-PLC and PI-PLC), hemolysins, in particular hemolysin BL (HBL), and various enterotoxins. The contribution of some of these toxins to B. thuringiensis pathogenicity has been studied in animal models of infection, following intravitreous, intranasal, or intratracheal inoculation. These studies lead to the speculation that the activities of PC-PLC, PI-PLC, and HBL are responsible for most of the pathogenic properties of B. thuringiensis in nongastrointestinal infections in mammals. This review summarizes data regarding the biological activity, the genetic basis, and the structural features of these membrane-damaging toxins.
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Affiliation(s)
- Francesco Celandroni
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
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10
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Grauffel C, Yang B, He T, Roberts MF, Gershenson A, Reuter N. Cation-π interactions as lipid-specific anchors for phosphatidylinositol-specific phospholipase C. J Am Chem Soc 2013; 135:5740-50. [PMID: 23506313 PMCID: PMC3797534 DOI: 10.1021/ja312656v] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Amphitropic proteins, such as the virulence factor phosphatidylinositol-specific phospholipase C (PI-PLC) from Bacillus thuringiensis , often depend on lipid-specific recognition of target membranes. However, the recognition mechanisms for zwitterionic lipids, such as phosphatidylcholine, which is enriched in the outer leaflet of eukaryotic cells, are not well understood. A 500 ns long molecular dynamics simulation of PI-PLC at the surface of a lipid bilayer revealed a strikingly high number of interactions between tyrosines at the interfacial binding site and lipid choline groups with structures characteristic of cation-π interactions. Membrane affinities of PI-PLC tyrosine variants mostly tracked the simulation results, falling into two classes: (i) those with minor losses in affinity, Kd(mutant)/Kd(wild-type) ≤ 5 and (ii) those where the apparent Kd was 50-200 times higher than wild-type. Estimating ΔΔG for these Tyr/PC interactions from the apparent Kd values reveals that the free energy associated with class I is ~1 kcal/mol, comparable to the value predicted by the Wimley-White hydrophobicity scale. In contrast, removal of class II tyrosines has a higher energy cost: ~2.5 kcal/mol toward pure PC vesicles. These higher energies correlate well with the occupancy of the cation-π adducts throughout the MD simulation. Together, these results strongly indicate that PI-PLC interacts with PC headgroups via cation-π interactions with tyrosine residues and suggest that cation-π interactions at the interface may be a mechanism for specific lipid recognition by amphitropic and membrane proteins.
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Affiliation(s)
- Cédric Grauffel
- Department of Molecular Biology, University of Bergen, Norway
- Computational Biology Unit, Uni Research, Bergen, Norway
| | - Boqian Yang
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, U.S.A
- Department of Chemistry, Boston College, Chestnut Hill, U.S.A
| | - Tao He
- Department of Chemistry, Boston College, Chestnut Hill, U.S.A
| | - Mary F. Roberts
- Department of Chemistry, Boston College, Chestnut Hill, U.S.A
| | - Anne Gershenson
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, U.S.A
| | - Nathalie Reuter
- Department of Molecular Biology, University of Bergen, Norway
- Computational Biology Unit, Uni Research, Bergen, Norway
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Cheng J, Goldstein R, Gershenson A, Stec B, Roberts MF. The cation-π box is a specific phosphatidylcholine membrane targeting motif. J Biol Chem 2013; 288:14863-73. [PMID: 23576432 DOI: 10.1074/jbc.m113.466532] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Peripheral membrane proteins can be targeted to specific organelles or the plasma membrane by differential recognition of phospholipid headgroups. Although molecular determinants of specificity for several headgroups, including phosphatidylserine and phosphoinositides are well defined, specific recognition of the headgroup of the zwitterionic phosphatidylcholine (PC) is less well understood. In cytosolic proteins the cation-π box provides a suitable receptor for choline recognition and binding through the trimethylammonium moiety. In PC, this moiety might provide a sufficient handle to bind to peripheral proteins via a cation-π cage, where the π systems of two or more aromatic residues are within 4-5 Å of the quaternary amine. We prove this hypothesis by engineering the cation-π box into secreted phosphatidylinositol-specific phospholipase C from Staphylococcus aureus, which lacks specific PC recognition. The N254Y/H258Y variant selectively binds PC-enriched vesicles, and x-ray crystallography reveals N254Y/H258Y binds choline and dibutyroylphosphatidylcholine within the cation-π motif. Such simple PC recognition motifs could be engineered into a wide variety of secondary structures providing a generally applicable method for specific recognition of PC.
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Affiliation(s)
- Jiongjia Cheng
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, USA
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