1
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Yang H, Zhou D, Zhou Z, Duan M, Yu H. Mechanistic Insight into the Mechanical Unfolding of the Integral Membrane Diacylglycerol Kinase. JACS AU 2024; 4:1422-1435. [PMID: 38665647 PMCID: PMC11040704 DOI: 10.1021/jacsau.3c00829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 02/29/2024] [Accepted: 03/01/2024] [Indexed: 04/28/2024]
Abstract
The essential forces stabilizing membrane proteins and governing their folding and unfolding are difficult to decipher. Single-molecule atomic force spectroscopy mechanically unfolds individual membrane proteins and quantifies their dynamics and energetics. However, it remains challenging to structurally assign unfolding intermediates precisely and to deduce dominant interactions between specific residues that facilitate either the localized stabilization of these intermediates or the global assembly of membrane proteins. Here, we performed force spectroscopy experiments and multiscale molecular dynamics simulations to study the unfolding pathway of diacylglycerol kinase (DGK), a small trimeric multispan transmembrane enzyme. The remarkable agreement between experiments and simulations allowed precise structural assignment and interaction analysis of unfolding intermediates, bypassing existing limitations on structural mapping, and thus provided mechanistic explanations for the formation of these states. DGK unfolding was found to proceed with structural segments varying in size that do not correlate with its secondary structure. We identified intermolecular side-chain packing interactions as one of the major contributions to the stability of unfolding intermediates. Mutagenesis creating packing defects induced a dramatic decrease in the mechano-stability of corresponding intermediates and also in the thermo-stability of DGK trimer, in good agreement with predictions from simulations. Hence, the molecular determinants of the mechano- and thermo-stability of a membrane protein can be identified at residue resolution. The accurate structural assignment established and microscopic mechanism revealed in this work may substantially expand the scope of single-molecule studies of membrane proteins.
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Affiliation(s)
- Huiying Yang
- School
of Physics, Huazhong University of Science
and Technology, Wuhan 430074, China
| | - Daihong Zhou
- School
of Physics, Huazhong University of Science
and Technology, Wuhan 430074, China
| | - Zhangyi Zhou
- School
of Physics, Huazhong University of Science
and Technology, Wuhan 430074, China
| | - Mojie Duan
- Innovation
Academy for Precision Measurement Science and Technology, Chinese
Academy of Sciences, Wuhan 430071, China
| | - Hao Yu
- School
of Physics, Huazhong University of Science
and Technology, Wuhan 430074, China
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2
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Ostroumova OS, Efimova SS. Lipid-Centric Approaches in Combating Infectious Diseases: Antibacterials, Antifungals and Antivirals with Lipid-Associated Mechanisms of Action. Antibiotics (Basel) 2023; 12:1716. [PMID: 38136750 PMCID: PMC10741038 DOI: 10.3390/antibiotics12121716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/05/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023] Open
Abstract
One of the global challenges of the 21st century is the increase in mortality from infectious diseases against the backdrop of the spread of antibiotic-resistant pathogenic microorganisms. In this regard, it is worth targeting antibacterials towards the membranes of pathogens that are quite conservative and not amenable to elimination. This review is an attempt to critically analyze the possibilities of targeting antimicrobial agents towards enzymes involved in pathogen lipid biosynthesis or towards bacterial, fungal, and viral lipid membranes, to increase the permeability via pore formation and to modulate the membranes' properties in a manner that makes them incompatible with the pathogen's life cycle. This review discusses the advantages and disadvantages of each approach in the search for highly effective but nontoxic antimicrobial agents. Examples of compounds with a proven molecular mechanism of action are presented, and the types of the most promising pharmacophores for further research and the improvement of the characteristics of antibiotics are discussed. The strategies that pathogens use for survival in terms of modulating the lipid composition and physical properties of the membrane, achieving a balance between resistance to antibiotics and the ability to facilitate all necessary transport and signaling processes, are also considered.
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Affiliation(s)
- Olga S. Ostroumova
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave. 4, St. Petersburg 194064, Russia;
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3
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Braun C, Wingen LM, Menche D. Strategies and tactics for the synthesis of lipid I and II and shortened analogues: functional building blocks of bacterial cell wall biosynthesis. Nat Prod Rep 2023; 40:1718-1734. [PMID: 37492928 DOI: 10.1039/d3np00018d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
Covering: the literature up to 2022This study discusses various synthetic strategies for the synthesis of lipid II, the pivotal bacterial cell wall precursor. In detail, it examines different solution phase approaches, reviews various solid phase sequences, and evaluates enzymatic ventures. The underlying rationale, scope, limitations, and perspectives of these strategies are discussed. The focus is on the tactics and strategies towards the authentic peptidoglycan compound, as well as analogues thereof with shortened side chains, which are increasingly recognized as more beneficial surrogates with more favorable physicochemical properties.
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Affiliation(s)
- Christina Braun
- Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, D-53121 Bonn, Germany.
| | - Lukas Martin Wingen
- Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, D-53121 Bonn, Germany.
| | - Dirk Menche
- Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, D-53121 Bonn, Germany.
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4
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Raghavan PS, Potnis AA, Gupta S, Gadly T, Kushwah N, Rajaram H. Interlink between ExoD (Alr2882), exopolysaccharide synthesis and metal tolerance in Nostoc sp. strain PCC 7120: Insight into its role, paralogs and evolution. Int J Biol Macromol 2023; 242:125014. [PMID: 37230445 DOI: 10.1016/j.ijbiomac.2023.125014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 05/15/2023] [Accepted: 05/19/2023] [Indexed: 05/27/2023]
Abstract
Exopolysaccharides (EPS) produced by bacterial species are an important component of bacteria's survival strategy. Synthesis of EPS, principal component of extracellular polymeric substance, occurs through multiple pathways involving multitude of genes. While stress-induced concomitant increase in exoD transcript levels and EPS content have been shown earlier, experimental evidence for direct correlation is lacking. In the present study, role of ExoD in Nostoc sp. strain PCC 7120 was evaluated by generating a recombinant Nostoc strain AnexoD+, wherein the ExoD (Alr2882) protein was constitutively overexpressed. AnexoD+ exhibited higher EPS production, propensity for formation of biofilms and tolerance to Cd stress compared to vector control AnpAM cells. Both Alr2882 and its paralog All1787 exhibited 5 transmembrane domains, with only All1787 predicted to interact with several proteins in polysaccharide synthesis. Phylogenetic analysis of orthologs of these proteins across cyanobacteria indicated that the two paralogs Alr2882 and All1787 and their corresponding orthologs arose divergently during evolution, and could have distinct roles to perform in the biosynthesis of EPS. This study has thrown open the possibility of engineering overproduction of EPS and inducing biofilm formation through genetic manipulation of EPS biosynthesis genes in cyanobacteria, thus building a cost-effective green platform for large scale production of EPS.
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Affiliation(s)
- Prashanth S Raghavan
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Akhilesh A Potnis
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Sumit Gupta
- Food Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India; Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, India
| | - Trilochan Gadly
- BioOrganic Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Nisha Kushwah
- Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Hema Rajaram
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India; Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, India.
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5
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Tu GW, Zhang Y, Ma JF, Hou JY, Hao GW, Su Y, Luo JC, Sheng L, Luo Z. Extracellular vesicles derived from CD4 + T cells carry DGKK to promote sepsis-induced lung injury by regulating oxidative stress and inflammation. Cell Mol Biol Lett 2023; 28:24. [PMID: 36959535 PMCID: PMC10035494 DOI: 10.1186/s11658-023-00435-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 02/28/2023] [Indexed: 03/25/2023] Open
Abstract
BACKGROUND Sepsis is an abnormal immune response after infection, wherein the lung is the most susceptible organ to fail, leading to acute lung injury. To overcome the limitations of current therapeutic strategies and develop more specific treatment, the inflammatory process, in which T cell-derived extracellular vesicles (EVs) play a central role, should be explored deeply. METHODS Liquid chromatography-tandem mass spectrometry was performed for serum EV protein profiling. The serum diacylglycerol kinase kappa (DGKK) and endotoxin contents of patients with sepsis-induced lung injury were measured. Apoptosis, oxidative stress, and inflammation in A549 cells, bronchoalveolar lavage fluid, and lung tissues of mice were measured by flow cytometry, biochemical analysis, enzyme-linked immunosorbent assay, quantitative real-time polymerase chain reaction, and western blot. RESULTS DGKK, the key regulator of the diacylglycerol (DAG)/protein kinase C (PKC) pathway, exhibited elevated expression in serum EVs of patients with sepsis-induced lung injury and showed strong correlation with sepsis severity and disease progression. DGKK was expressed in CD4+ T cells under regulation of the NF-κB pathway and delivered by EVs to target cells, including alveolar epithelial cells. EVs produced by CD4+ T lymphocytes exerted toxic effects on A549 cells to induce apoptotic cell death, oxidative cell damage, and inflammation. In mice with sepsis induced by cecal ligation and puncture, EVs derived from CD4+ T cells also promoted tissue damage, oxidative stress, and inflammation in the lungs. These toxic effects of T cell-derived EVs were attenuated by the inhibition of PKC and NOX4, the downstream effectors of DGKK and DAG. CONCLUSIONS This approach established the mechanism that T-cell-derived EVs carrying DGKK triggered alveolar epithelial cell apoptosis, oxidative stress, inflammation, and tissue damage in sepsis-induced lung injury through the DAG/PKC/NOX4 pathway. Thus, T-cell-derived EVs and the elevated distribution of DGKK should be further investigated to develop therapeutic strategies for sepsis-induced lung injury.
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Affiliation(s)
- Guo-Wei Tu
- Cardiac Intensive Care Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yi Zhang
- Biomedical Research Center, Institute for Clinical Sciences, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jie-Fei Ma
- Department of Critical Care Medicine, Zhongshan Hospital (Xiamen), Fudan University, Xiamen, China
| | - Jun-Yi Hou
- Cardiac Intensive Care Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Guang-Wei Hao
- Cardiac Intensive Care Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Ying Su
- Cardiac Intensive Care Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jing-Chao Luo
- Cardiac Intensive Care Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Lulu Sheng
- Department of Emergency Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.
| | - Zhe Luo
- Cardiac Intensive Care Center, Zhongshan Hospital, Fudan University, Shanghai, China.
- Department of Critical Care Medicine, Zhongshan Hospital (Xiamen), Fudan University, Xiamen, China.
- Shanghai Key Laboratory of Lung Inflammation and Injury, Shanghai, China.
- Department of Critical Care Medicine, Shanghai Xuhui Central Hospital, Zhongshan-Xuhui Hospital, Fudan University, Shanghai, China.
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6
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Peng H, Li J, Xu H, Wang X, He L, McCauley N, Zhang KK, Xie L. Offspring NAFLD liver phospholipid profiles are differentially programmed by maternal high-fat diet and maternal one carbon supplement. J Nutr Biochem 2023; 111:109187. [PMID: 36270572 DOI: 10.1016/j.jnutbio.2022.109187] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 06/23/2022] [Accepted: 09/15/2022] [Indexed: 11/07/2022]
Abstract
Little is known if and how maternal diet affects the liver phospholipid profiles that contribute to non-alcoholic fatty liver disease (NAFLD) development in offspring. We examined NAFLD phenotypes in male offspring mice of either maternal normal-fat diet (NF group), maternal high-fat diet (HF group), maternal methionine supplement (H1S group), or complete one-carbon supplement (H2S group) added to the maternal HF diet during gestation and lactation. HF offspring displayed worsened NAFLD phenotypes induced by post-weaning HF diet, however, maternal one-carbon supplement prevented such outcome. HF offspring also showed a distinct phospholipid profile from the offspring exposed to H1S or H2S diet. Whole genome bisulfite sequencing (WGBS) analysis further identified five pathways involved in phospholipid metabolism altered by different maternal diet interventions. Furthermore, differential methylated regions (DMRs) on Prkca, Dgkh, Plcb1 and Dgki were identified comparing between HF and NF offspring; most of these DMRs were recovered in H2S offspring. These methylation pattern changes were associated with gene expression changes: HF diet significantly reduced while H1S and H2S diet recovered their levels. Maternal HF diet disrupted offspring phospholipid profiles contributing to worsened hepatic steatosis. The maternal one-carbon supplement prevented such effects, probably through DNA methylation modification.
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Affiliation(s)
- Hui Peng
- Department of Nutrition, Texas A&M University, College Station, Texas, USA
| | - Jiangyuan Li
- Department of Nutrition, Texas A&M University, College Station, Texas, USA; Department of Statistics, Texas A&M University, College Station, Texas, USA
| | - Huiting Xu
- Department of Pathology, University of North Dakota, Grand Forks, North Dakota, USA
| | - Xian Wang
- Department of Nutrition, Texas A&M University, College Station, Texas, USA
| | - Leya He
- Department of Nutrition, Texas A&M University, College Station, Texas, USA
| | - Naomi McCauley
- Department of Nutrition, Texas A&M University, College Station, Texas, USA
| | - Ke K Zhang
- Department of Nutrition, Texas A&M University, College Station, Texas, USA; Center for Epigenetics & Disease Prevention, Institute of Biosciences & Technology, College of Medicine, Texas A&M University, Houston, Texas, USA; Department of Pathology, University of North Dakota, Grand Forks, North Dakota, USA.
| | - Linglin Xie
- Department of Nutrition, Texas A&M University, College Station, Texas, USA.
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7
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Flores J, Brea RJ, Lamas A, Fracassi A, Salvador-Castell M, Xu C, Baiz CR, Sinha SK, Devaraj NK. Rapid and Sequential Dual Oxime Ligation Enables De Novo Formation of Functional Synthetic Membranes from Water-Soluble Precursors. Angew Chem Int Ed Engl 2022; 61:e202200549. [PMID: 35546783 DOI: 10.1002/anie.202200549] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Indexed: 01/28/2023]
Abstract
Cell membranes define the boundaries of life and primarily consist of phospholipids. Living organisms assemble phospholipids by enzymatically coupling two hydrophobic tails to a soluble polar head group. Previous studies have taken advantage of micellar assembly to couple single-chain precursors, forming non-canonical phospholipids. However, biomimetic nonenzymatic coupling of two alkyl tails to a polar head-group remains challenging, likely due to the sluggish reaction kinetics of the initial coupling step. Here we demonstrate rapid de novo formation of biomimetic liposomes in water using dual oxime bond formation between two alkyl chains and a phosphocholine head group. Membranes can be generated from non-amphiphilic, water-soluble precursors at physiological conditions using micromolar concentrations of precursors. We demonstrate that functional membrane proteins can be reconstituted into synthetic oxime liposomes from bacterial extracts in the absence of detergent-like molecules.
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Affiliation(s)
- Judith Flores
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, Natural Sciences Building 3328, La Jolla, CA 92093, USA
| | - Roberto J Brea
- Biomimetic Membrane Chemistry (BioMemChem) Group, Centro de Investigacións Científicas Avanzadas (CICA), Universidade da Coruña, Rúa As Carballeiras, 15701, A Coruña, Spain
| | - Alejandro Lamas
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, Natural Sciences Building 3328, La Jolla, CA 92093, USA
| | - Alessandro Fracassi
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, Natural Sciences Building 3328, La Jolla, CA 92093, USA
| | - Marta Salvador-Castell
- Department of Physics, University of California, San Diego, 9500 Gilman Drive, Building: Mayer Hall Addition 4561, La Jolla, CA 92093, USA
| | - Cong Xu
- Department of Chemistry, The University of Texas at Austin, 105 E. 24th St. Stop A5300, Austin, TX 78712-1224, USA
| | - Carlos R Baiz
- Department of Chemistry, The University of Texas at Austin, 105 E. 24th St. Stop A5300, Austin, TX 78712-1224, USA
| | - Sunil K Sinha
- Department of Physics, University of California, San Diego, 9500 Gilman Drive, Building: Mayer Hall Addition 4561, La Jolla, CA 92093, USA
| | - Neal K Devaraj
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, Natural Sciences Building 3328, La Jolla, CA 92093, USA
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8
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Flores J, Brea RJ, Lamas A, Fracassi A, Salvador‐Castell M, Xu C, Baiz CR, Sinha SK, Devaraj NK. Rapid and Sequential Dual Oxime Ligation Enables De Novo Formation of Functional Synthetic Membranes from Water‐Soluble Precursors. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202200549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Judith Flores
- Department of Chemistry and Biochemistry University of California, San Diego 9500 Gilman Drive, Natural Sciences Building 3328 La Jolla CA 92093 USA
| | - Roberto J. Brea
- Biomimetic Membrane Chemistry (BioMemChem) Group Centro de Investigacións Científicas Avanzadas (CICA) Universidade da Coruña Rúa As Carballeiras 15701 A Coruña Spain
| | - Alejandro Lamas
- Department of Chemistry and Biochemistry University of California, San Diego 9500 Gilman Drive, Natural Sciences Building 3328 La Jolla CA 92093 USA
| | - Alessandro Fracassi
- Department of Chemistry and Biochemistry University of California, San Diego 9500 Gilman Drive, Natural Sciences Building 3328 La Jolla CA 92093 USA
| | - Marta Salvador‐Castell
- Department of Physics University of California, San Diego 9500 Gilman Drive, Building: Mayer Hall Addition 4561 La Jolla CA 92093 USA
| | - Cong Xu
- Department of Chemistry The University of Texas at Austin 105 E. 24th St. Stop A5300 Austin TX 78712-1224 USA
| | - Carlos R. Baiz
- Department of Chemistry The University of Texas at Austin 105 E. 24th St. Stop A5300 Austin TX 78712-1224 USA
| | - Sunil K. Sinha
- Department of Physics University of California, San Diego 9500 Gilman Drive, Building: Mayer Hall Addition 4561 La Jolla CA 92093 USA
| | - Neal K. Devaraj
- Department of Chemistry and Biochemistry University of California, San Diego 9500 Gilman Drive, Natural Sciences Building 3328 La Jolla CA 92093 USA
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9
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Drown them in their own garbage: a new strategy to reverse polymyxin resistance? J Bacteriol 2021; 204:e0057421. [PMID: 34843378 DOI: 10.1128/jb.00574-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Purcell and colleagues offer new insights into a major mechanism of polymyxin resistance in Gram-negative bacteria. Inactivating a single lipid recycling enzyme causes accumulation of waste lipid by-products that inhibit a key factor responsible for polymyxin resistance.
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10
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Bialas F, Becker CFW. Biomimetic Silica Encapsulation of Lipid Nanodiscs and β-Sheet-Stabilized Diacylglycerol Kinase. Bioconjug Chem 2021; 32:1742-1752. [PMID: 34288667 PMCID: PMC8382255 DOI: 10.1021/acs.bioconjchem.1c00260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 07/08/2021] [Indexed: 12/21/2022]
Abstract
Integral membrane proteins (IMPs) comprise highly important classes of proteins such as transporters, sensors, and channels, but their investigation and biotechnological application are complicated by the difficulty to stabilize them in solution. We set out to develop a biomimetic procedure to encapsulate functional integral membrane proteins in silica to facilitate their handling under otherwise detrimental conditions and thereby extend their applicability. To this end, we designed and expressed new fusion constructs of the membrane scaffold protein MSP with silica-precipitating peptides based on the R5 sequence from the diatom Cylindrotheca fusiformis. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) revealed that membrane lipid nanodiscs surrounded by our MSP variants fused to an R5 peptide, so-called nanodiscs, were formed. Exposing them to silicic acid led to silica-encapsulated nanodiscs, a new material for stabilizing membrane structures and a first step toward incorporating membrane proteins in such structures. In an alternative approach, four fusion constructs based on the amphiphilic β-sheet peptide BP-1 and the R5 peptide were generated and successfully employed toward silica encapsulation of functional diacylglycerol kinase (DGK). Silica-encapsulated DGK was significantly more stable against protease exposure and incubation with simulated gastric fluid (SGF) and intestinal fluid (SIF).
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Affiliation(s)
- Friedrich Bialas
- Institute of Biological Chemistry,
Faculty of Chemistry, University of Vienna, Währinger Straße 38, 1090 Vienna, Austria
| | - Christian F. W. Becker
- Institute of Biological Chemistry,
Faculty of Chemistry, University of Vienna, Währinger Straße 38, 1090 Vienna, Austria
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11
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Woodall BM, Harp JR, Brewer WT, Tague ED, Campagna SR, Fozo EM. Enterococcus faecalis Readily Adapts Membrane Phospholipid Composition to Environmental and Genetic Perturbation. Front Microbiol 2021; 12:616045. [PMID: 34093456 PMCID: PMC8177052 DOI: 10.3389/fmicb.2021.616045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 04/15/2021] [Indexed: 11/22/2022] Open
Abstract
The bacterial lipid membrane, consisting both of fatty acid (acyl) tails and polar head groups, responds to changing conditions through alteration of either the acyl tails and/or head groups. This plasticity is critical for cell survival as it allows maintenance of both the protective nature of the membrane as well as functioning membrane protein complexes. Bacteria that live in fatty-acid rich environments, such as those found in the human host, can exploit host fatty acids to synthesize their own membranes, in turn, altering their physiology. Enterococcus faecalis is such an organism: it is a commensal of the mammalian intestine where it is exposed to fatty-acid rich bile, as well as a major cause of hospital infections during which it is exposed to fatty acid containing-serum. Within, we employed an untargeted approach to detect the most common phospholipid species of E. faecalis OG1RF via ultra-high performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS). We examined not only how the composition responds upon exposure to host fatty acids but also how deletion of genes predicted to synthesize major polar head groups impact lipid composition. Regardless of genetic background and differing basal lipid composition, all strains were able to alter their lipid composition upon exposure to individual host fatty acids. Specific gene deletion strains, however, had altered survival to membrane damaging agents. Combined, the enterococcal lipidome is highly resilient in response to both genetic and environmental perturbation, likely contributing to stress survival.
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Affiliation(s)
- Brittni M. Woodall
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - John R. Harp
- Department of Microbiology, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - William T. Brewer
- Department of Microbiology, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Eric D. Tague
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Shawn R. Campagna
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, TN, United States
- Biological and Small Molecule Mass Spectrometry Core, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Elizabeth M. Fozo
- Department of Microbiology, University of Tennessee, Knoxville, Knoxville, TN, United States
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12
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Structure of membrane diacylglycerol kinase in lipid bilayers. Commun Biol 2021; 4:282. [PMID: 33674677 PMCID: PMC7935881 DOI: 10.1038/s42003-021-01802-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 02/05/2021] [Indexed: 12/17/2022] Open
Abstract
Diacylglycerol kinase (DgkA) is a small integral membrane protein, responsible for the ATP-dependent phosphorylation of diacylglycerol to phosphatidic acid. Its structures reported in previous studies, determined in detergent micelles by solution NMR and in monoolein cubic phase by X-ray crystallography, differ significantly. These differences point to the need to validate these detergent-based structures in phospholipid bilayers. Here, we present a well-defined homo-trimeric structure of DgkA in phospholipid bilayers determined by magic angle spinning solid-state NMR (ssNMR) spectroscopy, using an approach combining intra-, inter-molecular paramagnetic relaxation enhancement (PRE)-derived distance restraints and CS-Rosetta calculations. The DgkA structure determined in lipid bilayers is different from the solution NMR structure. In addition, although ssNMR structure of DgkA shows a global folding similar to that determined by X-ray, these two structures differ in monomeric symmetry and dynamics. A comparative analysis of DgkA structures determined in three different detergent/lipid environments provides a meaningful demonstration of the influence of membrane mimetic environments on the structure and dynamics of membrane proteins. Jianping Li et al. present the homo-trimeric structure of the small integral membrane protein diacylglycerol kinase (DgkA) in phospholipid bilayers determined by magic angle spinning solid-state NMR spectroscopy. They compare the structure with structures solved by solution NMR and X-ray crystallography and provide insights into the influence of membrane mimetic environments on membrane proteins.
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13
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Baker BR, Ives CM, Bray A, Caffrey M, Cochrane SA. Undecaprenol kinase: Function, mechanism and substrate specificity of a potential antibiotic target. Eur J Med Chem 2020; 210:113062. [PMID: 33310291 DOI: 10.1016/j.ejmech.2020.113062] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 10/22/2022]
Abstract
The bifunctional undecaprenol kinase/phosphatase (UdpK) is a small, prokaryotic, integral membrane kinase, homologous with Escherichia coli diacylglycerol kinase and expressed by the dgkA gene. In Gram-positive bacteria, UdpK is involved in the homeostasis of the bacterial undecaprenoid pool, where it converts undecaprenol to undecaprenyl phosphate (C55P) and also catalyses the reverse process. C55P is the universal lipid carrier and critical to numerous glycopolymer and glycoprotein biosynthetic pathways in bacteria. DgkA gene expression has been linked to facilitating bacterial growth and survival in response to environmental stressors, as well being implicated as a resistance mechanism to the topical antibiotic bacitracin, by providing an additional route to C55P. Therefore, identification of UdpK inhibitors could lead to novel antibiotic treatments. A combination of homology modelling and mutagenesis experiments on UdpK have been used to identify residues that may be involved in kinase/phosphatase activity. In this review, we will summarise recent work on the mechanism and substrate specificity of UdpK.
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Affiliation(s)
- Brad R Baker
- School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Stranmillis Road, Belfast, BT9 5AG, UK
| | - Callum M Ives
- School of Medicine and School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160, Pearse Street, Dublin 2, D02 R590, Ireland; Division of Computational Biology, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Ashley Bray
- School of Medicine and School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160, Pearse Street, Dublin 2, D02 R590, Ireland
| | - Martin Caffrey
- School of Medicine and School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160, Pearse Street, Dublin 2, D02 R590, Ireland.
| | - Stephen A Cochrane
- School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Stranmillis Road, Belfast, BT9 5AG, UK.
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14
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Harrison LM, Lacher DW, Mammel MK, Leonard SR. Comparative Transcriptomics of Shiga Toxin-Producing and Commensal Escherichia coli and Cytokine Responses in Colonic Epithelial Cell Culture Infections. Front Cell Infect Microbiol 2020; 10:575630. [PMID: 33194815 PMCID: PMC7649339 DOI: 10.3389/fcimb.2020.575630] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 10/07/2020] [Indexed: 12/12/2022] Open
Abstract
Ingestion of Shiga toxin-producing Escherichia coli (STEC) can result in a range of illness severity from asymptomatic to hemorrhagic colitis and death; thus risk assessment of STEC strains for human pathogenicity is important in the area of food safety. Illness severity depends in part on the combination of virulence genes carried in the genome, which can vary between strains even of identical serotype. To better understand how core genes are regulated differently among strains and to identify possible novel STEC virulence gene candidates that could be added to the risk assessment repertoire, we used comparative transcriptomics to investigate global gene expression differences between two STEC strains associated with severe illness and a commensal E. coli strain during in vitro intestinal epithelial cell (IEC) infections. Additionally, we compared a wide array of concomitant cytokine levels produced by the IECs. The cytokine expression levels were examined for a pattern representing STEC pathogenicity; however, while one STEC strain appeared to elicit a proinflammatory response, infection by the other strain produced a pattern comparable to the commensal E. coli. This result may be explained by the significant differences in gene content and expression observed between the STEC strains. RNA-Seq analysis revealed considerable disparity in expression of genes in the arginine and tryptophan biosynthesis/import pathways between the STEC strains and the commensal E. coli strain, highlighting the important role some amino acids play in STEC colonization and survival. Contrasting differential expression patterns were observed for genes involved in respiration among the three strains suggesting that metabolic diversity is a strategy utilized to compete with resident microflora for successful colonization. Similar temporal expression results for known and putative virulence genes were observed in the STEC strains, revealing strategies used for survival prior to and after initial adherence to IECs. Additionally, three genes encoding hypothetical proteins located in mobile genetic elements were, after interrogation of a large set of E. coli genomes, determined to likely represent novel STEC virulence factors.
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Affiliation(s)
- Lisa M Harrison
- Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD, United States
| | - David W Lacher
- Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD, United States
| | - Mark K Mammel
- Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD, United States
| | - Susan R Leonard
- Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD, United States
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15
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Gallardo A, Ugarte-Ruiz M, Hernández M, Miguela-Villoldo P, Rodríguez-Lázaro D, Domínguez L, Quesada A. Involvement of hpap2 and dgkA Genes in Colistin Resistance Mediated by mcr Determinants. Antibiotics (Basel) 2020; 9:antibiotics9090531. [PMID: 32842668 PMCID: PMC7559476 DOI: 10.3390/antibiotics9090531] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 08/19/2020] [Accepted: 08/21/2020] [Indexed: 11/16/2022] Open
Abstract
Plasmid-mediated colistin resistance (mcr) determinants are challenging the efficacy of polymyxins against Gram-negative pathogens. Among 10 mcr genes described so far, the major determinants mcr-1 and mcr-3 are found closely linked to hpap2 or dgkA genes, encoding a hypothetical phosphatidic acid phosphatase of type 2 (PAP2) and a diacylglycerol kinase, respectively, whose functions are still unknown. In this study, mcr-1, mcr-1–hpap2, mcr-3, and mcr-3–dgkA were expressed in Escherichia coli, and recombinant strains were analyzed to detect antimicrobial susceptibility and changes in the expression of genes involved in phospholipid metabolism. The mcr-1 or mcr-3 single genes were enough to drive growth on colistin selective media, although co-expression of linked genes conferred maximal antibiotic resistance. Expression of mcr determinants downregulated endogenous genes involved in lipopolysaccharide (LPS) modification or phospholipid recycling, although to different extents of repression: strong for arnB, ybjG, and pmrR; medium for eptA, lpxT, and dgkA; small for bacA and pgpB. Four of these genes (bacA, lpxT, pgpB, and ybjG) encode undecaprenyl pyrophosphate (UPP) phosphatases. In these conditions, cells presented resistance against bacitracin, an antibiotic that sequesters UPP from PAP2 enzymes. The hpap2 and dgkA genes might play a role in colistin resistance by compensating for phospholipid metabolism functions altered during LPS modification by colistin resistance determinants.
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Affiliation(s)
- Alejandro Gallardo
- Departamento de Bioquímica, Facultad de Veterinaria, Universidad de Extremadura, Av. de la Universidad s/n, 10003 Cáceres, Spain;
| | - María Ugarte-Ruiz
- VISAVET Health Surveillance Centre, Universidad Complutense de Madrid, 28040 Madrid, Spain; (M.U.-R.); (P.M.-V.); (L.D.)
| | - Marta Hernández
- Laboratorio de Biología Molecular y Microbiología, Instituto Tecnológico Agrario de Castilla y León, 47071 Valladolid, Spain;
| | - Pedro Miguela-Villoldo
- VISAVET Health Surveillance Centre, Universidad Complutense de Madrid, 28040 Madrid, Spain; (M.U.-R.); (P.M.-V.); (L.D.)
| | - David Rodríguez-Lázaro
- Unidad de Microbiología, Departamento de Biotecnología y Ciencia de los Alimentos, Universidad de Burgos, 09001 Burgos, Spain;
| | - Lucas Domínguez
- VISAVET Health Surveillance Centre, Universidad Complutense de Madrid, 28040 Madrid, Spain; (M.U.-R.); (P.M.-V.); (L.D.)
| | - Alberto Quesada
- Departamento de Bioquímica, Facultad de Veterinaria, Universidad de Extremadura, Av. de la Universidad s/n, 10003 Cáceres, Spain;
- INBIO G + C, Universidad de Extremadura, 10003 Cáceres, Spain
- Correspondence: ; Tel.: +34-927251334
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16
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Workman SD, Strynadka NCJ. A Slippery Scaffold: Synthesis and Recycling of the Bacterial Cell Wall Carrier Lipid. J Mol Biol 2020; 432:4964-4982. [PMID: 32234311 DOI: 10.1016/j.jmb.2020.03.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 03/18/2020] [Accepted: 03/25/2020] [Indexed: 01/20/2023]
Abstract
The biosynthesis of bacterial cell envelope polysaccharides such as peptidoglycan relies on the use of a dedicated carrier lipid both for the assembly of precursors at the cytoplasmic face of the plasma membrane and for the translocation of lipid linked oligosaccharides across the plasma membrane into the periplasmic space. This dedicated carrier lipid, undecaprenyl phosphate, results from the dephosphorylation of undecaprenyl pyrophosphate, which is generated de novo in the cytoplasm by undecaprenyl pyrophosphate synthase and released as a by-product when newly synthesized glycans are incorporated into the existing cell envelope. The de novo synthesis of undecaprenyl pyrophosphate has been thoroughly characterized from a structural and mechanistic standpoint; however, its dephosphorylation to the active carrier lipid form, both in the course of de novo synthesis and recycling, has only been begun to be studied in depth in recent years. This review provides an overview of bacterial carrier lipid synthesis and presents the current state of knowledge regarding bacterial carrier lipid recycling.
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Affiliation(s)
- Sean D Workman
- Department of Biochemistry and Molecular Biology and the Center for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, Canada V6T 1Z3
| | - Natalie C J Strynadka
- Department of Biochemistry and Molecular Biology and the Center for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, Canada V6T 1Z3.
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17
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Structure and Functional Characterization of Membrane Integral Proteins in the Lipid Cubic Phase. J Mol Biol 2020; 432:5104-5123. [PMID: 32113953 DOI: 10.1016/j.jmb.2020.02.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 02/14/2020] [Accepted: 02/19/2020] [Indexed: 12/19/2022]
Abstract
The lipid cubic phase (LCP) has been used extensively as a medium for crystallizing membrane proteins. It is an attractive environment in which to perform such studies because it incorporates a lipid bilayer. It is therefore considered a useful and a faithful biomembrane mimetic. Here, we bring together evidence that supports this view. Biophysical characterizations are described demonstrating that the cubic phase is a porous medium into and out of which water-soluble molecules can diffuse for binding to and reaction with reconstituted proteins. The proteins themselves are shown to be functionally reconstituted into and to have full mobility in the bilayered membrane, a prerequisite for LCP crystallogenesis. Spectroscopic methods have been used to characterize the conformation and disposition of proteins in the mesophase. Procedures for performing activity assays on enzymes directly in the cubic phase have been reported. Specific examples described here include a kinase and two transferases, where quantitative kinetics and mechanism-defining measurements were performed directly or via a coupled assay system. Finally, ligand-binding assays are described, where binding to proteins in the mesophase membrane was monitored directly by eye and indirectly by fluorescence quenching, enabling binding constant determinations for targets with affinity values in the micromolar and nanomolar range. These results make a convincing case that the lipid bilayer of the cubic mesophase is an excellent membrane mimetic and a suitable medium in which to perform not only crystallogenesis but also biochemical and biophysical characterizations of membrane proteins.
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18
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Cai H, Yao H, Li T, Tang Y, Li D. High-level heterologous expression of the human transmembrane sterol Δ8,Δ7-isomerase in Pichia pastoris. Protein Expr Purif 2019; 164:105463. [DOI: 10.1016/j.pep.2019.105463] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 07/30/2019] [Indexed: 01/11/2023]
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19
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Marinko J, Huang H, Penn WD, Capra JA, Schlebach JP, Sanders CR. Folding and Misfolding of Human Membrane Proteins in Health and Disease: From Single Molecules to Cellular Proteostasis. Chem Rev 2019; 119:5537-5606. [PMID: 30608666 PMCID: PMC6506414 DOI: 10.1021/acs.chemrev.8b00532] [Citation(s) in RCA: 153] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Indexed: 12/13/2022]
Abstract
Advances over the past 25 years have revealed much about how the structural properties of membranes and associated proteins are linked to the thermodynamics and kinetics of membrane protein (MP) folding. At the same time biochemical progress has outlined how cellular proteostasis networks mediate MP folding and manage misfolding in the cell. When combined with results from genomic sequencing, these studies have established paradigms for how MP folding and misfolding are linked to the molecular etiologies of a variety of diseases. This emerging framework has paved the way for the development of a new class of small molecule "pharmacological chaperones" that bind to and stabilize misfolded MP variants, some of which are now in clinical use. In this review, we comprehensively outline current perspectives on the folding and misfolding of integral MPs as well as the mechanisms of cellular MP quality control. Based on these perspectives, we highlight new opportunities for innovations that bridge our molecular understanding of the energetics of MP folding with the nuanced complexity of biological systems. Given the many linkages between MP misfolding and human disease, we also examine some of the exciting opportunities to leverage these advances to address emerging challenges in the development of therapeutics and precision medicine.
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Affiliation(s)
- Justin
T. Marinko
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Hui Huang
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Wesley D. Penn
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - John A. Capra
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
- Department
of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37245, United States
| | - Jonathan P. Schlebach
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Charles R. Sanders
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
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20
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Global response of diacylglycerol kinase towards substrate binding observed by 2D and 3D MAS NMR. Sci Rep 2019; 9:3995. [PMID: 30850624 PMCID: PMC6408475 DOI: 10.1038/s41598-019-40264-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 02/11/2019] [Indexed: 01/01/2023] Open
Abstract
Escherichia coli diacylglycerol kinase (DGK) is an integral membrane protein, which catalyses the ATP-dependent phosphorylation of diacylglycerol (DAG) to phosphatic acid (PA). It is a unique trimeric enzyme, which does not share sequence homology with typical kinases. It exhibits a notable complexity in structure and function despite of its small size. Here, chemical shift assignment of wild-type DGK within lipid bilayers was carried out based on 3D MAS NMR, utilizing manual and automatic analysis protocols. Upon nucleotide binding, extensive chemical shift perturbations could be observed. These data provide evidence for a symmetric DGK trimer with all of its three active sites concurrently occupied. Additionally, we could detect that the nucleotide substrate induces a substantial conformational change, most likely directing DGK into its catalytic active form. Furthermore, functionally relevant interprotomer interactions are identified by DNP-enhanced MAS NMR in combination with site-directed mutagenesis and functional assays.
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21
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Ma Q, Gabelli SB, Raben DM. Diacylglycerol kinases: Relationship to other lipid kinases. Adv Biol Regul 2019; 71:104-110. [PMID: 30348515 PMCID: PMC6347529 DOI: 10.1016/j.jbior.2018.09.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 09/24/2018] [Accepted: 09/25/2018] [Indexed: 04/17/2023]
Abstract
Lipid kinases regulate a wide variety of cellular functions and have emerged as one the most promising targets for drug design. Diacylglycerol kinases (DGKs) are a family of enzymes that catalyze the ATP-dependent phosphorylation of diacylglycerol (DAG) to phosphatidic acid (PtdOH). Despite the critical role in lipid biosynthesis, both DAG and PtdOH have been shown as bioactive lipids mediating a number of signaling pathways. Although there is increasing recognition of their role in signaling systems, our understanding of the key enzyme which regulate the balance of these two lipid messages remain limited. Solved structures provide a wealth of information for understanding the function and regulation of these enzymes. Solving the structures of mammalian DGKs by traditional NMR and X-ray crystallography approaches have been challenging and so far, there are still no three-dimensional structures of these DGKs. Despite this, some insights may be gained by examining the similarities and differences between prokaryotic DGKs and other mammalian lipid kinases. This review focuses on summarizing and comparing the structure of prokaryotic and mammalian DGKs as well as two other lipid kinases: sphingosine kinase and phosphatidylinositol-3-kinase. How these known lipid kinases structures relate to mammalian DGKs will also be discussed.
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Affiliation(s)
- Qianqian Ma
- The Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Sandra B Gabelli
- The Department of Biophysics, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Daniel M Raben
- The Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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22
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Flood JJ, Copley SD. Genome-Wide Analysis of Transcriptional Changes and Genes That Contribute to Fitness during Degradation of the Anthropogenic Pollutant Pentachlorophenol by Sphingobium chlorophenolicum. mSystems 2018; 3:e00275-18. [PMID: 30505947 PMCID: PMC6247019 DOI: 10.1128/msystems.00275-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 11/01/2018] [Indexed: 12/02/2022] Open
Abstract
Pentachlorophenol (PCP) is a highly toxic pesticide that was first introduced in the 1930s. The alphaproteobacterium Sphingobium chlorophenolicum, which was isolated from PCP-contaminated sediment, has assembled a metabolic pathway capable of completely degrading PCP. This pathway produces four toxic intermediates, including a chlorinated benzoquinone that is a potent alkylating agent and three chlorinated hydroquinones that react with O2 to produce reactive oxygen species (ROS). RNA-seq analysis revealed that PCP causes a global stress response that resembles responses to proton motive force uncoupling and membrane disruption, while surprisingly, little of the response resembles the responses expected to be produced by the PCP degradation intermediates. Tn-seq was used to identify genes important for fitness in the presence of PCP. By comparing the genes that are important for fitness in wild-type S. chlorophenolicum and a non-PCP-degrading mutant, we identified genes that are important only when the PCP degradation intermediates are produced. These include genes encoding two enzymes that are likely to be involved in protection against ROS. In addition to these enzymes, the endogenous levels of other enzymes that protect cells from oxidative stress appear to mitigate the toxic effects of the chlorinated benzoquinone and hydroquinone metabolites of PCP. The combination of RNA-seq and Tn-seq results identify important mechanisms for defense against the toxicity of PCP. IMPORTANCE Phenolic compounds such as pentachlorophenol (PCP), triclosan, and 2,4-dichlorophenoxyacetic acid (2,4-D) represent a common class of anthropogenic biocides. Despite the novelty of these compounds, many can be degraded by microbes isolated from contaminated sites. However, degradation of this class of chemicals often generates toxic intermediates, which may contribute to their recalcitrance to biodegradation. We have addressed the stresses associated with degradation of PCP by Sphingobium chlorophenolicum by examining the transcriptional response after PCP exposure and identifying genes necessary for growth during both exposure to and degradation of PCP. This work identifies some of the mechanisms that protect cells from this toxic compound and facilitate its degradation. This information could be used to engineer strains capable of improved biodegradation of PCP or similar phenolic pollutants.
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Affiliation(s)
- Jake J. Flood
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
- Cooperative Institute for Environmental Sciences, University of Colorado Boulder, Boulder, Colorado, USA
| | - Shelley D. Copley
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
- Cooperative Institute for Environmental Sciences, University of Colorado Boulder, Boulder, Colorado, USA
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23
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Kawakami N, Fujisaki S. Undecaprenyl phosphate metabolism in Gram-negative and Gram-positive bacteria. Biosci Biotechnol Biochem 2018; 82:940-946. [DOI: 10.1080/09168451.2017.1401915] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
Undecaprenyl phosphate (UP) is essential for the biosynthesis of bacterial extracellular polysaccharides. UP is produced by the dephosphorylation of undecaprenyl diphosphate (UPP) via de novo synthetic and recycling pathways. Gram-positive bacteria contain remarkable amounts of undecaprenol (UOH), which is phosphorylated to UP, although UOH has not been found in Gram-negative bacteria. Here, current knowledge about UPP phosphatase and UOH kinase is reviewed. Dephosphorylation of UPP is catalyzed by a BacA homologue and a type-2 phosphatidic acid phosphatase (PAP2) homologue. The presence of one of these UPP phosphatases is essential for bacterial growth. The catalytic center of both types of enzyme is located outside the cytoplasmic membrane. In Gram-positive bacteria, an enzyme homologous to DgkA, which is the diacylglycerol kinase of Escherichia coli, catalyzes UOH phosphorylation. The possible role of UOH and the significance of systematic construction of Staphylococcus aureus mutants to determine UP metabolism are discussed.
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Affiliation(s)
- Naoki Kawakami
- Faculty of Science, Department of Biomolecular Science, Toho University, Funabashi, Japan
| | - Shingo Fujisaki
- Faculty of Science, Department of Biomolecular Science, Toho University, Funabashi, Japan
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24
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Membrane properties that shape the evolution of membrane enzymes. Curr Opin Struct Biol 2018; 51:80-91. [PMID: 29597094 DOI: 10.1016/j.sbi.2018.03.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 03/14/2018] [Accepted: 03/15/2018] [Indexed: 02/07/2023]
Abstract
Spectacular recent progress in structural biology has led to determination of the structures of many integral membrane enzymes that catalyze reactions in which at least one substrate also is membrane bound. A pattern of results seems to be emerging in which the active site chemistry of these enzymes is usually found to be analogous to what is observed for water soluble enzymes catalyzing the same reaction types. However, in light of the chemical, structural, and physical complexity of cellular membranes plus the presence of transmembrane gradients and potentials, these enzymes may be subject to membrane-specific regulatory mechanisms that are only now beginning to be uncovered. We review the membrane-specific environmental traits that shape the evolution of membrane-embedded biocatalysts.
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25
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Radeck J, Lautenschläger N, Mascher T. The Essential UPP Phosphatase Pair BcrC and UppP Connects Cell Wall Homeostasis during Growth and Sporulation with Cell Envelope Stress Response in Bacillus subtilis. Front Microbiol 2017; 8:2403. [PMID: 29259598 PMCID: PMC5723303 DOI: 10.3389/fmicb.2017.02403] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 11/20/2017] [Indexed: 12/03/2022] Open
Abstract
The bacterial cell wall separates the cell from its surrounding and protects it from environmental stressors. Its integrity is maintained by a highly regulated process of cell wall biosynthesis. The membrane-located lipid II cycle provides cell wall building blocks that are assembled inside the cytoplasm to the outside for incorporation. Its carrier molecule, undecaprenyl phosphate (UP), is then recycled by dephosphorylation from undecaprenyl pyrophosphate (UPP). In Bacillus subtilis, this indispensable reaction is catalyzed by the UPP phosphatases BcrC and UppP. Here, we study the physiological function of both phosphatases with respect to morphology, cell wall homeostasis and the resulting cell envelope stress response (CESR). We demonstrate that uppP and bcrC represent a synthetic lethal gene pair, which encodes an essential physiological function. Accordingly, cell growth and morphology were severely impaired during exponential growth if the overall UPP phosphatase level was limiting. UppP, but not BcrC, was crucial for normal sporulation. Expression of bcrC, but not uppP, was upregulated in the presence of cell envelope stress conditions caused by bacitracin if UPP phosphatase levels were limited. This homeostatic feedback renders BcrC more important during growth than UppP, particularly in defense against cell envelope stress.
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Affiliation(s)
- Jara Radeck
- Institute of Microbiology, Technische Universität Dresden, Dresden, Germany
| | | | - Thorsten Mascher
- Institute of Microbiology, Technische Universität Dresden, Dresden, Germany
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26
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Huang LY, Wang SC, Cheng TJR, Wong CH. Undecaprenyl Phosphate Phosphatase Activity of Undecaprenol Kinase Regulates the Lipid Pool in Gram-Positive Bacteria. Biochemistry 2017; 56:5417-5427. [PMID: 28872301 DOI: 10.1021/acs.biochem.7b00603] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bacteria cell walls contain many repeating glycan structures, such as peptidoglycans, lipopolysaccharides, teichoic acids, and capsular polysaccharides. Their synthesis starts in the cytosol, and they are constructed from a glycan lipid carrier, undecaprenyl phosphate (C55P), which is essential for cell growth and survival. The lipid derivative undecaprenol (C55OH) is predominant in many Gram-positive bacteria but has not been detected in Gram-negative bacteria; its origin and role have thus remained unknown. Recently, a homologue of diacylglycerol kinase (DgkA) in Escherichia coli (E. coli) was demonstrated to be an undecaprenol kinase (UK) in the Gram-positive bacterium Streptococcus mutans (S. mutans). In this study, we found that S. mutans UK was not only an undecaprenol kinase but also a Mg-ADP-dependent undecaprenyl phosphate phosphatase (UpP), catalyzing the hydrolysis of C55P to C55OH and a free inorganic phosphate. Furthermore, the naturally undetectable C55OH was observed in E. coli cells expressing S. mutans dgkA, supporting the phosphatase activity of UK/UpP in vivo. These two activities were indispensable to each other and utilized identical essential residues binding to their substrates, suggesting that both activities share the same active site and might involve a direct phosphoryl transfer mechanism. This study revealed a unique membrane enzyme displaying bifunctional activities determined by substrate binding and C55OH production. The reciprocal conversion of C55P and the undecaprenol pool efficiently regulate cell wall synthesis, especially in Gram-positive bacteria.
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Affiliation(s)
- Lin-Ya Huang
- Genomics Research Center, Academia Sinica , Taipei 115, Taiwan
| | - Shih-Chi Wang
- Genomics Research Center, Academia Sinica , Taipei 115, Taiwan.,Institute of Biochemistry and Molecular Biology, National Yang-Ming University , Taipei 112, Taiwan
| | | | - Chi-Huey Wong
- Genomics Research Center, Academia Sinica , Taipei 115, Taiwan.,Institute of Biochemistry and Molecular Biology, National Yang-Ming University , Taipei 112, Taiwan
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27
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Sharma R, Keshari D, Singh KS, Singh SK. Biochemical and functional characterization of MRA_1571 of Mycobacterium tuberculosis H37Ra and effect of its down-regulation on survival in macrophages. Biochem Biophys Res Commun 2017; 487:892-897. [PMID: 28465237 DOI: 10.1016/j.bbrc.2017.04.149] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 04/29/2017] [Indexed: 12/31/2022]
Abstract
Amino acid biosynthesis has emerged as a source of new drug targets as many bacterial strains auxotrophic for amino acids fail to proliferate under in vivo conditions. Branch chain amino acids (BCAAs) are important for Mycobacterium tuberculosis (Mtb) survival and strains deficient in their biosynthesis were attenuated for growth in mice. Threonine dehydratase (IlvA) is a pyridoxal-5-phosphate (PLP) dependent enzyme that catalyzes the first step in isoleucine biosynthesis. The MRA_1571 of Mycobacterium tuberculosis H37Ra (Mtb-Ra), annotated to be coding for IlvA, was cloned, expressed and purified. Purified protein was subsequently used for developing enzyme assay and to study its biochemical properties. Also, E. coli BL21 (DE3) IlvA knockout (E. coli-ΔilvA) was developed and genetically complemented with Mtb-Ra ilvA expression construct (pET32a-ilvA) to make complemented E. coli strain (E. coli-ΔilvA + pET32a-ilvA). The E. coli-ΔilvA showed growth failure in minimal medium but growth restoration was observed in E. coli-ΔilvA + pET32a-ilvA. E. coli-ΔilvA growth was also restored in the presence of isoleucine. The IlvA localization studies detected its distribution in cell wall and membrane fractions with relatively minor presence in cytosolic fraction. Maximum IlvA expression was observed at 72 h in wild-type (WT) Mtb-Ra infecting macrophages. Also, Mtb-Ra IlvA knockdown (KD) showed reduced survival in macrophages compared to WT and complemented strain (KDC).
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Affiliation(s)
- Rishabh Sharma
- Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow - 226031, India
| | - Deepa Keshari
- Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow - 226031, India
| | - Kumar Sachin Singh
- Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow - 226031, India
| | - Sudheer Kumar Singh
- Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow - 226031, India; Academy of Scientific and Industrial Research (AcSIR), New Delhi, India.
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Cacas JL, Gerbeau-Pissot P, Fromentin J, Cantrel C, Thomas D, Jeannette E, Kalachova T, Mongrand S, Simon-Plas F, Ruelland E. Diacylglycerol kinases activate tobacco NADPH oxidase-dependent oxidative burst in response to cryptogein. PLANT, CELL & ENVIRONMENT 2017; 40:585-598. [PMID: 27272019 DOI: 10.1111/pce.12771] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 05/23/2016] [Accepted: 05/24/2016] [Indexed: 05/20/2023]
Abstract
Cryptogein is a 10 kDa protein secreted by the oomycete Phytophthora cryptogea that activates defence mechanisms in tobacco plants. Among early signalling events triggered by this microbial-associated molecular pattern is a transient apoplastic oxidative burst which is dependent on the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity of the RESPIRATORY BURST OXIDASE HOMOLOG isoform D (RBOHD). Using radioactive [33 P]-orthophosphate labelling of tobacco Bright Yellow-2 suspension cells, we here provide in vivo evidence for a rapid accumulation of phosphatidic acid (PA) in response to cryptogein because of the coordinated onset of phosphoinositide-dependent phospholipase C and diacylglycerol kinase (DGK) activities. Both enzyme specific inhibitors and silencing of the phylogenetic cluster III of the tobacco DGK family were found to reduce PA production upon elicitation and to strongly decrease the RBOHD-mediated oxidative burst. Therefore, it appears that PA originating from DGK controls NADPH-oxidase activity. Amongst cluster III DGKs, the expression of DGK5-like was up-regulated in response to cryptogein. Besides DGK5-like is likely to be the main cluster III DGK isoform silenced in one of our mutant lines, making it a strong candidate for the observed response to cryptogein. The relevance of these results is discussed with regard to early signalling lipid-mediated events in plant immunity.
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Affiliation(s)
- Jean-Luc Cacas
- Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France
| | - Patricia Gerbeau-Pissot
- Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France
| | - Jérôme Fromentin
- Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France
| | - Catherine Cantrel
- UPMC UnivParis06, UR5, Physiologie Cellulaire et Moléculaire des Plantes, 4 place Jussieu, 75252, Paris cedex 05, France
| | - Dominique Thomas
- Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France
| | - Emmanuelle Jeannette
- UPMC UnivParis06, UR5, Physiologie Cellulaire et Moléculaire des Plantes, 4 place Jussieu, 75252, Paris cedex 05, France
| | - Tetiana Kalachova
- UPE, UPEC, Institut d'Ecologie et des Sciences de l'Environnement de Paris, 61 avenue du général de Gaulle, 94010, Créteil, France
- CNRS, UMR7618, Institut d'Ecologie et des Sciences de l'Environnement de Paris, 61 avenue du général de Gaulle, 94010, Créteil, France
| | - Sébastien Mongrand
- CNRS, UMR 5200 Laboratoire de Biogenèse Membranaire, INRA Bordeaux Aquitaine, BP81, F-33883, Villenave d'Ornon, France
| | - Françoise Simon-Plas
- Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France
| | - Eric Ruelland
- UPMC UnivParis06, UR5, Physiologie Cellulaire et Moléculaire des Plantes, 4 place Jussieu, 75252, Paris cedex 05, France
- UPE, UPEC, Institut d'Ecologie et des Sciences de l'Environnement de Paris, 61 avenue du général de Gaulle, 94010, Créteil, France
- CNRS, UMR7618, Institut d'Ecologie et des Sciences de l'Environnement de Paris, 61 avenue du général de Gaulle, 94010, Créteil, France
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Baldanzi G, Bettio V, Malacarne V, Graziani A. Diacylglycerol Kinases: Shaping Diacylglycerol and Phosphatidic Acid Gradients to Control Cell Polarity. Front Cell Dev Biol 2016; 4:140. [PMID: 27965956 PMCID: PMC5126041 DOI: 10.3389/fcell.2016.00140] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Accepted: 11/14/2016] [Indexed: 12/24/2022] Open
Abstract
Diacylglycerol kinases (DGKs) terminate diacylglycerol (DAG) signaling and promote phosphatidic acid (PA) production. Isoform specific regulation of DGKs activity and localization allows DGKs to shape the DAG and PA gradients. The capacity of DGKs to constrain the areas of DAG signaling is exemplified by their role in defining the contact interface between T cells and antigen presenting cells: the immune synapse. Upon T cell receptor engagement, both DGK α and ζ metabolize DAG at the immune synapse thus constraining DAG signaling. Interestingly, their activity and localization are not fully redundant because DGKζ activity metabolizes the bulk of DAG in the cell, whereas DGKα limits the DAG signaling area localizing specifically at the periphery of the immune synapse. When DGKs terminate DAG signaling, the local PA production defines a new signaling domain, where PA recruits and activates a second wave of effector proteins. The best-characterized example is the role of DGKs in protrusion elongation and cell migration. Indeed, upon growth factor stimulation, several DGK isoforms, such as α, ζ, and γ, are recruited and activated at the plasma membrane. Here, local PA production controls cell migration by finely modulating cytoskeletal remodeling and integrin recycling. Interestingly, DGK-produced PA also controls the localization and activity of key players in cell polarity such as aPKC, Par3, and integrin β1. Thus, T cell polarization and directional migration may be just two instances of the general contribution of DGKs to the definition of cell polarity by local specification of membrane identity signaling.
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Affiliation(s)
- Gianluca Baldanzi
- Department of Translational Medicine, University of Piemonte OrientaleNovara, Italy; Institute for Research and Cure of Autoimmune DiseasesNovara, Italy
| | - Valentina Bettio
- Department of Translational Medicine, University of Piemonte OrientaleNovara, Italy; Institute for Research and Cure of Autoimmune DiseasesNovara, Italy
| | - Valeria Malacarne
- Department of Translational Medicine, University of Piemonte OrientaleNovara, Italy; Division of Experimental Oncology, School of Medicine, University Vita e Salute San RaffaeleMilan, Italy
| | - Andrea Graziani
- Department of Translational Medicine, University of Piemonte OrientaleNovara, Italy; Division of Experimental Oncology, School of Medicine, University Vita e Salute San RaffaeleMilan, Italy
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Nakano T, Matsui H, Tanaka T, Hozumi Y, Iseki K, Kawamae K, Goto K. Arachidonoyl-Specific Diacylglycerol Kinase ε and the Endoplasmic Reticulum. Front Cell Dev Biol 2016; 4:132. [PMID: 27917381 PMCID: PMC5114243 DOI: 10.3389/fcell.2016.00132] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 10/31/2016] [Indexed: 01/22/2023] Open
Abstract
The endoplasmic reticulum (ER) comprises an interconnected membrane network, which is made up of lipid bilayer and associated proteins. This organelle plays a central role in the protein synthesis and sorting. In addition, it represents the synthetic machinery of phospholipids, the major constituents of the biological membrane. In this process, phosphatidic acid (PA) serves as a precursor of all phospholipids, suggesting that PA synthetic activity is closely associated with the ER function. One enzyme responsible for PA synthesis is diacylglycerol kinase (DGK) that phosphorylates diacylglycerol (DG) to PA. DGK is composed of a family of enzymes with distinct features assigned to each isozyme in terms of structure, enzymology, and subcellular localization. Of DGKs, DGKε uniquely exhibits substrate specificity toward arachidonate-containing DG and is shown to reside in the ER. Arachidonic acid, a precursor of bioactive eicosanoids, is usually acylated at the sn-2 position of phospholipids, being especially enriched in phosphoinositide. In this review, we focus on arachidonoyl-specific DGKε with respect to the historical context, molecular basis of the substrate specificity and ER-targeting, and functional implications in the ER.
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Affiliation(s)
- Tomoyuki Nakano
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine Yamagata, Japan
| | - Hirooki Matsui
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine Yamagata, Japan
| | - Toshiaki Tanaka
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine Yamagata, Japan
| | - Yasukazu Hozumi
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine Yamagata, Japan
| | - Ken Iseki
- Department of Emergency and Critical Care Medicine, Fukushima Medical University School of Medicine Fukushima, Japan
| | - Kaneyuki Kawamae
- Department of Anesthesiology, Yamagata University School of Medicine Yamagata, Japan
| | - Kaoru Goto
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine Yamagata, Japan
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Tu-Sekine B, Goldschmidt HL, Raben DM. DGK-θ: Structure, Enzymology, and Physiological Roles. Front Cell Dev Biol 2016; 4:101. [PMID: 27683659 PMCID: PMC5021689 DOI: 10.3389/fcell.2016.00101] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 08/29/2016] [Indexed: 12/13/2022] Open
Abstract
Diacylglycerol kinases (DGKs) are a family of enzymes that catalyze the ATP-dependent phosphorylation of diacylglycerol (DAG) to phosphatidic acid (PtdOH). The recognition of the importance of these enzymes has been increasing ever since it was determined that they played a role in the phosphatidylinositol (PtdIns) cycle and a number of excellent reviews have already been written [(see van Blitterswijk and Houssa, 2000; Kanoh et al., 2002; Mérida et al., 2008; Tu-Sekine and Raben, 2009, 2011; Shulga et al., 2011; Tu-Sekine et al., 2013) among others]. We now know there are ten mammalian DGKs that are organized into five classes. DGK-θ is the lone member of the Type V class of DGKs and remains as one of the least studied. This review focuses on our current understanding of the structure, enzymology, regulation, and physiological roles of this DGK and suggests some future areas of research to understand this DGK isoform.
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Affiliation(s)
- Becky Tu-Sekine
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Hana L Goldschmidt
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Daniel M Raben
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine Baltimore, MD, USA
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Sahoo A, Khare S, Devanarayanan S, Jain PC, Varadarajan R. Residue proximity information and protein model discrimination using saturation-suppressor mutagenesis. eLife 2015; 4. [PMID: 26716404 PMCID: PMC4758949 DOI: 10.7554/elife.09532] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 12/29/2015] [Indexed: 12/16/2022] Open
Abstract
Identification of residue-residue contacts from primary sequence can be used to guide protein structure prediction. Using Escherichia coli CcdB as the test case, we describe an experimental method termed saturation-suppressor mutagenesis to acquire residue contact information. In this methodology, for each of five inactive CcdB mutants, exhaustive screens for suppressors were performed. Proximal suppressors were accurately discriminated from distal suppressors based on their phenotypes when present as single mutants. Experimentally identified putative proximal pairs formed spatial constraints to recover >98% of native-like models of CcdB from a decoy dataset. Suppressor methodology was also applied to the integral membrane protein, diacylglycerol kinase A where the structures determined by X-ray crystallography and NMR were significantly different. Suppressor as well as sequence co-variation data clearly point to the X-ray structure being the functional one adopted in vivo. The methodology is applicable to any macromolecular system for which a convenient phenotypic assay exists. DOI:http://dx.doi.org/10.7554/eLife.09532.001 Common techniques to determine the three-dimensional structures of proteins can help researchers to understand these molecules’ activities, but are often time-consuming and do not work for all proteins. Proteins are made of chains of amino acids. When a protein chain folds, some of these amino acids interact with other amino acids and these contacts dictate the overall shape of the protein. This means that identifying the pairs of contacting amino acids could make it possible to predict the protein’s structure. Interactions between pairs of contacting amino acids tend to remain conserved throughout evolution, and if a mutation alters one of the amino acids in a pair then a 'compensatory' change often occurs to alter the second amino acid as well. Compensatory mutations can suggest that two amino acids are close to each other in the three-dimensional shape of a protein, but the computational methods used to identify such amino acid pairs can sometimes be inaccurate. In 2012, researchers generated mutants of a bacterial protein called CcdB with changes to single amino acids that caused the protein to fail to fold correctly. Now, Sahoo et al. – who include two of the researchers involved in the 2012 work – have developed an experimental method to identify contacting amino acids and use the CcdB protein as a test case. The approach involved searching for additional mutations that could restore the activity of five of the original mutant proteins when the proteins were produced in yeast cells. The rationale was that any secondary mutations that restored the activity must have corrected the folding defect caused by the original mutation. Sahoo et al. then predicted how close the amino acids affected by the secondary mutations were to the amino acids altered by the original mutations. This information was used to select reliable three-dimensional models of CcdB from a large set of possible structures that had been generated previously using computer models. Next, the technique was applied to a protein called diacylglycerol kinase A. The structure of this protein had previously been inferred using techniques such as X-ray crystallography and nuclear magnetic resonance, but there was a mismatch between the two methods. Sahoo et al. found that the amino acid contacts derived from their experimental method matched those found in the crystal structure, suggesting that the functional protein structure in living cells is similar to the crystal structure. In the future, the experimental approach developed in this work could be combined with existing methods to reliably guide protein structure prediction. DOI:http://dx.doi.org/10.7554/eLife.09532.002
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Affiliation(s)
- Anusmita Sahoo
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Shruti Khare
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | | | - Pankaj C Jain
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Raghavan Varadarajan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India.,Jawaharlal Nehru Center for Advanced Scientific Research, Bangalore, India
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Ternary structure reveals mechanism of a membrane diacylglycerol kinase. Nat Commun 2015; 6:10140. [PMID: 26673816 PMCID: PMC4703834 DOI: 10.1038/ncomms10140] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Accepted: 11/09/2015] [Indexed: 11/24/2022] Open
Abstract
Diacylglycerol kinase catalyses the ATP-dependent conversion of diacylglycerol to phosphatidic acid in the plasma membrane of Escherichia coli. The small size of this integral membrane trimer, which has 121 residues per subunit, means that available protein must be used economically to craft three catalytic and substrate-binding sites centred about the membrane/cytosol interface. How nature has accomplished this extraordinary feat is revealed here in a crystal structure of the kinase captured as a ternary complex with bound lipid substrate and an ATP analogue. Residues, identified as essential for activity by mutagenesis, decorate the active site and are rationalized by the ternary structure. The γ-phosphate of the ATP analogue is positioned for direct transfer to the primary hydroxyl of the lipid whose acyl chain is in the membrane. A catalytic mechanism for this unique enzyme is proposed. The active site architecture shows clear evidence of having arisen by convergent evolution. Diacylglycerol kinase is a small bacterial membrane-bound trimer that catalyses diacylglycerol conversion to phosphatidic acid. Here, the authors solve the crystal structure of the kinase bound to a lipid substrate and an ATP analogue, and show that the active site arose through convergent evolution.
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Molecular properties of diacylglycerol kinase-epsilon in relation to function. Chem Phys Lipids 2015; 192:100-108. [PMID: 26134136 DOI: 10.1016/j.chemphyslip.2015.06.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 06/21/2015] [Indexed: 01/12/2023]
Abstract
The epsilon isoform of mammalian diacylglycerol kinase (DGKϵ) is an enzyme that associates strongly with membranes and acts on a lipid substrate, diacylglycerol. The protein has one segment that is predicted to be a transmembrane helix, but appears to interconvert between a transmembrane helix and a re-entrant helix. Despite the hydrophobicity of this segment and the fact that the lipid substrate is also hydrophobic, removal of this hydrophobic segment by truncating the protein at the amino terminus has no effect on its enzymatic activity. The amino acid sequence of the catalytic segment of DGKϵ is highly homologous to that of a bacterial DGK, DgkB. This has allowed us to predict a conformation of DGKϵ based on the known crystal structure of DgkB. An important property of DGKϵ is that it is specific for diacylglycerol species containing an arachidonoyl group. The region of DGKϵ that interacts with this group is found within the accessory domain of the protein and not in the active site nor in the hydrophobic amino terminus. The nature of the acyl chain specificity of the enzyme indicates that DGKϵ is associated with the synthesis of phosphatidylinositol. Defects or deletion of the enzyme give rise to several disease states.
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An HD-domain phosphodiesterase mediates cooperative hydrolysis of c-di-AMP to affect bacterial growth and virulence. Proc Natl Acad Sci U S A 2015; 112:E747-56. [PMID: 25583510 DOI: 10.1073/pnas.1416485112] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The nucleotide cyclic di-3',5'- adenosine monophosphate (c-di-AMP) was recently identified as an essential and widespread second messenger in bacterial signaling. Among c-di-AMP-producing bacteria, altered nucleotide levels result in several physiological defects and attenuated virulence. Thus, a detailed molecular understanding of c-di-AMP metabolism is of both fundamental and practical interest. Currently, c-di-AMP degradation is recognized solely among DHH-DHHA1 domain-containing phosphodiesterases. Using chemical proteomics, we identified the Listeria monocytogenes protein PgpH as a molecular target of c-di-AMP. Biochemical and structural studies revealed that the PgpH His-Asp (HD) domain bound c-di-AMP with high affinity and specifically hydrolyzed this nucleotide to 5'-pApA. PgpH hydrolysis activity was inhibited by ppGpp, indicating a cross-talk between c-di-AMP signaling and the stringent response. Genetic analyses supported coordinated regulation of c-di-AMP levels in and out of the host. Intriguingly, a L. monocytogenes mutant that lacks c-di-AMP phosphodiesterases exhibited elevated c-di-AMP levels, hyperinduced a host type-I IFN response, and was significantly attenuated for infection. Furthermore, PgpH homologs, which belong to the 7TMR-HD family, are widespread among hundreds of c-di-AMP synthesizing microorganisms. Thus, PgpH represents a broadly conserved class of c-di-AMP phosphodiesterase with possibly other physiological functions in this crucial signaling network.
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Li D, Pye VE, Caffrey M. Experimental phasing for structure determination using membrane-protein crystals grown by the lipid cubic phase method. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2015; 71:104-22. [PMID: 25615865 PMCID: PMC4304691 DOI: 10.1107/s1399004714010360] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 05/07/2014] [Indexed: 03/02/2023]
Abstract
Despite the marked increase in the number of membrane-protein structures solved using crystals grown by the lipid cubic phase or in meso method, only ten have been determined by SAD/MAD. This is likely to be a consequence of the technical difficulties associated with handling proteins and crystals in the sticky and viscous hosting mesophase that is usually incubated in glass sandwich plates for the purposes of crystallization. Here, a four-year campaign aimed at phasing the in meso structure of the integral membrane diacylglycerol kinase (DgkA) from Escherichia coli is reported. Heavy-atom labelling of this small hydrophobic enzyme was attempted by pre-labelling, co-crystallization, soaking, site-specific mercury binding to genetically engineered single-cysteine mutants and selenomethionine incorporation. Strategies and techniques for special handling are reported, as well as the typical results and the lessons learned for each of these approaches. In addition, an assay to assess the accessibility of cysteine residues in membrane proteins for mercury labelling is introduced. The various techniques and strategies described will provide a valuable reference for future experimental phasing of membrane proteins where crystals are grown by the lipid cubic phase method.
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Affiliation(s)
- Dianfan Li
- Membrane Structural and Functional Group, School of Medicine and School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
| | - Valerie E. Pye
- Membrane Structural and Functional Group, School of Medicine and School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
| | - Martin Caffrey
- Membrane Structural and Functional Group, School of Medicine and School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
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Murray DT, Li C, Gao FP, Qin H, Cross TA. Membrane protein structural validation by oriented sample solid-state NMR: diacylglycerol kinase. Biophys J 2014; 106:1559-69. [PMID: 24739155 DOI: 10.1016/j.bpj.2014.02.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 01/29/2014] [Accepted: 02/12/2014] [Indexed: 12/28/2022] Open
Abstract
The validation of protein structures through functional assays has been the norm for many years. Functional assays perform this validation for water-soluble proteins very well, but they need to be performed in the same environment as that used for the structural analysis. This is difficult for membrane proteins that are often structurally characterized in detergent environments, although functional assays for these proteins are most frequently performed in lipid bilayers. Because the structure of membrane proteins is known to be sensitive to the membrane mimetic environment, such functional assays are appropriate for validating the protein construct, but not the membrane protein structure. Here, we compare oriented sample solid-state NMR spectral data of diacylglycerol kinase previously published with predictions of such data from recent structures of this protein. A solution NMR structure of diacylglycerol kinase has been obtained in detergent micelles and three crystal structures have been obtained in a monoolein cubic phase. All of the structures are trimeric with each monomer having three transmembrane and one amphipathic helices. However, the solution NMR structure shows typical perturbations induced by a micelle environment that is reflected in the predicted solid-state NMR resonances from the structural coordinates. The crystal structures show few such perturbations, especially for the wild-type structure and especially for the monomers that do not have significant crystal contacts. For these monomers the predicted and observed data are nearly identical. The thermostabilized constructs do show more perturbations, especially the A41C mutation that introduces a hydrophilic residue into what would be the middle of the lipid bilayer inducing additional hydrogen bonding between trimers. These results demonstrate a general technique for validating membrane protein structures with minimal data obtained from membrane proteins in liquid crystalline lipid bilayers by oriented sample solid-state NMR.
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Affiliation(s)
- Dylan T Murray
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida; Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida
| | - Conggang Li
- State Key Laboratory of Magnetic Resonance and Molecular and Atomic Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, PR China
| | - F Philip Gao
- Del Shankel Structural Biology Center, University of Kansas, Lawrence, Kansas
| | - Huajun Qin
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida; Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida
| | - Timothy A Cross
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida; Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida; Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida.
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Zhang Z, Chen Y, Tang X, Li J, Wang L, Yang J. Solid-state NMR shows that dynamically different domains of membrane proteins have different hydration dependence. J Phys Chem B 2014; 118:9553-64. [PMID: 25026099 DOI: 10.1021/jp503032h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hydration has a profound influence on the structure, dynamics, and functions of membrane and membrane-embedded proteins. So far the hydration response of molecular dynamics of membrane proteins in lipid bilayers is poorly understood. Here, we reveal different hydration dependence of the dynamics in dynamically different domains of membrane proteins by multidimensional magic angle spinning (MAS) solid-state NMR (ssNMR) spectroscopy using 121-residue integral diacylglycerol kinase (DAGK) in 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)/1,2-dimyristoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DMPG) lipid bilayers as a model system. The highly mobile and immobile domains of DAGK and their water accessibilities are identified site-specifically by scalar- and dipolar-coupling based MAS ssNMR experiments, respectively. Our experiments reveal different hydration dependence of the dynamics in highly mobile and immobile domains of membrane proteins. We demonstrate that the fast, large-amplitude motions in highly mobile domains are not triggered until 20% hydration, enhanced at 20-50% hydration and unchanged at above 50% hydration. In contrast, motions on submicrosecond time scale of immobile residues are observed to be independent of the hydration levels in gel phase of lipids, and at the temperature near gel-liquid crystalline phase transition, amplitude of whole-molecule rotations around the bilayer normal is dominated by the fluidity of lipid bilayers, which is strongly hydration dependent. The hydration dependence of the dynamics of DAGK revealed by this study provides new insights into the correlations of hydration to dynamics and function of membrane proteins in lipid bilayers.
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Affiliation(s)
- Zhengfeng Zhang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences , Wuhan 430071, P. R. China
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Renaturing membrane proteins in the lipid cubic phase, a nanoporous membrane mimetic. Sci Rep 2014; 4:5806. [PMID: 25055873 PMCID: PMC4108929 DOI: 10.1038/srep05806] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 06/23/2014] [Indexed: 12/31/2022] Open
Abstract
Membrane proteins play vital roles in the life of the cell and are important therapeutic targets. Producing them in large quantities, pure and fully functional is a major challenge. Many promising projects end when intractable aggregates or precipitates form. Here we show how such unfolded aggregates can be solubilized and the solution mixed with lipid to spontaneously self-assemble a bicontinuous cubic mesophase into the bilayer of which the protein, in a confined, chaperonin-like environment, reconstitutes with 100% efficiency. The test protein, diacylglycerol kinase, reconstituted in the bilayer of the mesophase, was then crystallized in situ by the in meso or lipid cubic phase method providing an X-ray structure to a resolution of 2.55 Å. This highly efficient, inexpensive, simple and rapid approach should find application wherever properly folded, membrane reconstituted and functional proteins are required where the starting material is a denatured aggregate.
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40
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Caffrey M, Li D, Howe N, Shah STA. 'Hit and run' serial femtosecond crystallography of a membrane kinase in the lipid cubic phase. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130621. [PMID: 24914170 PMCID: PMC4052879 DOI: 10.1098/rstb.2013.0621] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The lipid-based bicontinuous cubic mesophase is a nanoporous membrane mimetic with applications in areas that include medicine, personal care products, foods and the basic sciences. An application of particular note concerns it use as a medium in which to grow crystals of membrane proteins for structure determination by X-ray crystallography. At least two variations of the mesophase exist. One is the highly viscous cubic phase, which has well developed long-range order. The other so-called sponge phase is considerably more fluid and lacks long-range order. The sponge phase has recently been shown to be a convenient vehicle for delivering microcrystals of membrane proteins to an X-ray free-electron laser beam for serial femtosecond crystallography (SFX). Unfortunately, the sponge phase approach calls for large amounts of protein that are not always available in the case of membrane proteins. The cubic phase offers the advantage of requiring significantly less protein for SFX but comes with its own challenges. Here, we describe the physico-chemical bases for these challenges, solutions to them and prospects for future uses of lipidic mesophases in the SFX arena.
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Affiliation(s)
- Martin Caffrey
- Membrane Structural and Functional Biology Group, School of Medicine and School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Republic of Ireland
| | - Dianfan Li
- Membrane Structural and Functional Biology Group, School of Medicine and School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Republic of Ireland
| | - Nicole Howe
- Membrane Structural and Functional Biology Group, School of Medicine and School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Republic of Ireland
| | - Syed T A Shah
- Membrane Structural and Functional Biology Group, School of Medicine and School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Republic of Ireland
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Huang LY, Huang SH, Chang YC, Cheng WC, Cheng TJR, Wong CH. Enzymatic synthesis of lipid II and analogues. Angew Chem Int Ed Engl 2014; 53:8060-5. [PMID: 24990652 DOI: 10.1002/anie.201402313] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 03/28/2014] [Indexed: 02/02/2023]
Abstract
The emergence of antibiotic resistance has prompted active research in the development of antibiotics with new modes of action. Among all essential bacterial proteins, transglycosylase polymerizes lipid II into peptidoglycan and is one of the most favorable targets because of its vital role in peptidoglycan synthesis. Described in this study is a practical enzymatic method for the synthesis of lipid II, coupled with cofactor regeneration, to give the product in a 50-70% yield. This development depends on two key steps: the overexpression of MraY for the synthesis of lipid I and the use of undecaprenol kinase for the preparation of polyprenol phosphates. This method was further applied to the synthesis of lipid II analogues. It was found that MraY and undecaprenol kinase can accept a wide range of lipids containing various lengths and configurations. The activity of lipid II analogues for bacterial transglycolase was also evaluated.
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Affiliation(s)
- Lin-Ya Huang
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 115 (Taiwan); Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 115 (Taiwan); Graduate Institute of Biotechnology, National Chung-Hsing, University, 250 Kuo Kuang Rd., Taichung 402 (Taiwan); Biotechnology Center, National Chung-Hsing University, 250 Kuo Kuang Rd., Taichung 402 (Taiwan)
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42
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Huang LY, Huang SH, Chang YC, Cheng WC, Cheng TJR, Wong CH. Enzymatic Synthesis of Lipid II and Analogues. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201402313] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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43
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Manat G, Roure S, Auger R, Bouhss A, Barreteau H, Mengin-Lecreulx D, Touzé T. Deciphering the metabolism of undecaprenyl-phosphate: the bacterial cell-wall unit carrier at the membrane frontier. Microb Drug Resist 2014; 20:199-214. [PMID: 24799078 DOI: 10.1089/mdr.2014.0035] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
During the biogenesis of bacterial cell-wall polysaccharides, such as peptidoglycan, cytoplasmic synthesized precursors should be trafficked across the plasma membrane. This essential process requires a dedicated lipid, undecaprenyl-phosphate that is used as a glycan lipid carrier. The sugar is linked to the lipid carrier at the inner face of the membrane and is translocated toward the periplasm, where the glycan moiety is transferred to the growing polymer. Undecaprenyl-phosphate originates from the dephosphorylation of its precursor undecaprenyl-diphosphate, with itself generated by de novo synthesis or by recycling after the final glycan transfer. Undecaprenyl-diphosphate is de novo synthesized by the cytosolic cis-prenyltransferase undecaprenyl-diphosphate synthase, which has been structurally and mechanistically characterized in great detail highlighting the condensation process. In contrast, the next step toward the formation of the lipid carrier, the dephosphorylation step, which has been overlooked for many years, has only started revealing surprising features. In contrast to the previous step, two unrelated families of integral membrane proteins exhibit undecaprenyl-diphosphate phosphatase activity: BacA and members of the phosphatidic acid phosphatase type 2 super-family, raising the question of the significance of this multiplicity. Moreover, these enzymes establish an unexpected link between the synthesis of bacterial cell-wall polymers and other biological processes. In the present review, the current knowledge in the field of the bacterial lipid carrier, its mechanism of action, biogenesis, recycling, regulation, and future perspective works are presented.
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Affiliation(s)
- Guillaume Manat
- Laboratoire des Enveloppes Bactériennes et Antibiotiques, IBBMC, UMR 8619 CNRS, Université Paris Sud , Orsay Cedex, France
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44
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Chen Y, Zhang Z, Tang X, Li J, Glaubitz C, Yang J. Conformation and Topology of Diacylglycerol Kinase inE.coliMembranes Revealed by Solid-state NMR Spectroscopy. Angew Chem Int Ed Engl 2014; 53:5624-8. [DOI: 10.1002/anie.201311203] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Revised: 02/05/2014] [Indexed: 01/04/2023]
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45
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Chen Y, Zhang Z, Tang X, Li J, Glaubitz C, Yang J. Conformation and Topology of Diacylglycerol Kinase inE.coliMembranes Revealed by Solid-state NMR Spectroscopy. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201311203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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46
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Cross TA, Ekanayake V, Paulino J, Wright A. Solid state NMR: The essential technology for helical membrane protein structural characterization. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 239:100-9. [PMID: 24412099 PMCID: PMC3957465 DOI: 10.1016/j.jmr.2013.12.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 12/03/2013] [Accepted: 12/09/2013] [Indexed: 05/21/2023]
Abstract
NMR spectroscopy of helical membrane proteins has been very challenging on multiple fronts. The expression and purification of these proteins while maintaining functionality has consumed countless graduate student hours. Sample preparations have depended on whether solution or solid-state NMR spectroscopy was to be performed - neither have been easy. In recent years it has become increasingly apparent that membrane mimic environments influence the structural result. Indeed, in these recent years we have rediscovered that Nobel laureate, Christian Anfinsen, did not say that protein structure was exclusively dictated by the amino acid sequence, but rather by the sequence in a given environment (Anfinsen, 1973) [106]. The environment matters, molecular interactions with the membrane environment are significant and many examples of distorted, non-native membrane protein structures have recently been documented in the literature. However, solid-state NMR structures of helical membrane proteins in proteoliposomes and bilayers are proving to be native structures that permit a high resolution characterization of their functional states. Indeed, solid-state NMR is uniquely able to characterize helical membrane protein structures in lipid environments without detergents. Recent progress in expression, purification, reconstitution, sample preparation and in the solid-state NMR spectroscopy of both oriented samples and magic angle spinning samples has demonstrated that helical membrane protein structures can be achieved in a timely fashion. Indeed, this is a spectacular opportunity for the NMR community to have a major impact on biomedical research through the solid-state NMR spectroscopy of these proteins.
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Affiliation(s)
- Timothy A Cross
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA; Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA; Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA.
| | - Vindana Ekanayake
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA; Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA
| | - Joana Paulino
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA; Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
| | - Anna Wright
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA; Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
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Boronat A, Rodríguez-Concepción M. Terpenoid biosynthesis in prokaryotes. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2014; 148:3-18. [PMID: 25523226 DOI: 10.1007/10_2014_285] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Prokaryotic organisms (archaea and eubacteria) are found in all habitats where life exists on our planet. This would not be possible without the astounding biochemical plasticity developed by such organisms. Part of the metabolic diversity of prokaryotes was transferred to eukaryotic cells when endosymbiotic prokaryotes became mitochondria and plastids but also in a large number of horizontal gene transfer episodes. A group of metabolites produced by all free-living organisms is terpenoids (also known as isoprenoids). In prokaryotes, terpenoids play an indispensable role in cell-wall and membrane biosynthesis (bactoprenol, hopanoids), electron transport (ubiquinone, menaquinone), or conversion of light into chemical energy (chlorophylls, bacteriochlorophylls, rhodopsins, carotenoids), among other processes. But despite their remarkable structural and functional diversity, they all derive from the same metabolic precursors. Here we describe the metabolic pathways producing these universal terpenoid units and provide a complete picture of the main terpenoid compounds found in prokaryotic organisms.
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Affiliation(s)
- Albert Boronat
- Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, 08193, Barcelona, Spain
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48
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Hopper JT, Yu YTC, Li D, Raymond A, Bostock M, Liko I, Mikhailov V, Laganowsky A, Benesch JL, Caffrey M, Nietlispach D, Robinson CV. Detergent-free mass spectrometry of membrane protein complexes. Nat Methods 2013; 10:1206-8. [PMID: 24122040 PMCID: PMC3868940 DOI: 10.1038/nmeth.2691] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 08/29/2013] [Indexed: 02/02/2023]
Abstract
We developed a method that allows release of intact membrane protein complexes from amphipols, bicelles and nanodiscs in the gas phase for observation by mass spectrometry (MS). Current methods involve release of membrane protein complexes from detergent micelles, which reveals subunit composition and lipid binding. We demonstrated that oligomeric complexes or proteins requiring defined lipid environments are stabilized to a greater extent in the absence of detergent.
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Affiliation(s)
- Jonathan T.S. Hopper
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ
| | - Yvonne Ting-Chun Yu
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA
| | - Dianfan Li
- School of Medicine Trinity College Dublin, Dublin, Ireland
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
| | - Alison Raymond
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ
| | - Mark Bostock
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA
| | - Idlir Liko
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ
| | - Victor Mikhailov
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ
| | - Arthur Laganowsky
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ
| | - Justin L.P. Benesch
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ
| | - Martin Caffrey
- School of Medicine Trinity College Dublin, Dublin, Ireland
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
| | - Daniel Nietlispach
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA
| | - Carol V. Robinson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ
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49
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Jefferson RE, Blois TM, Bowie JU. Membrane proteins can have high kinetic stability. J Am Chem Soc 2013; 135:15183-90. [PMID: 24032628 DOI: 10.1021/ja407232b] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Approximately 10% of water-soluble proteins are considered kinetically stable with unfolding half-lives in the range of weeks to millenia. These proteins only rarely sample the unfolded state and may never unfold on their respective biological time scales. It is still not known whether membrane proteins can be kinetically stable, however. Here we examine the subunit dissociation rate of the trimeric membrane enzyme, diacylglycerol kinase, from Escherichia coli as a proxy for complete unfolding. We find that dissociation occurs with a half-life of at least several weeks, demonstrating that membrane proteins can remain locked in a folded state for long periods of time. These results reveal that evolution can use kinetic stability to regulate the biological function of membrane proteins, as it can for soluble proteins. Moreover, it appears that the generation of kinetic stability could be a viable target for membrane protein engineering efforts.
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Affiliation(s)
- Robert E Jefferson
- Department of Chemistry and Biochemistry, University of California, Los Angeles-Department of Energy Institute for Genomics and Proteomics, Molecular Biology Institute, University of California, Los Angeles , Los Angeles, California 90095, United States
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50
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Bickford JS, Nick HS. Conservation of the PTEN catalytic motif in the bacterial undecaprenyl pyrophosphate phosphatase, BacA/UppP. MICROBIOLOGY-SGM 2013; 159:2444-2455. [PMID: 24068241 DOI: 10.1099/mic.0.070474-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Isoprenoid lipid carriers are essential in protein glycosylation and bacterial cell envelope biosynthesis. The enzymes involved in their metabolism (synthases, kinases and phosphatases) are therefore critical to cell viability. In this review, we focus on two broad groups of isoprenoid pyrophosphate phosphatases. One group, containing phosphatidic acid phosphatase motifs, includes the eukaryotic dolichyl pyrophosphate phosphatases and proposed recycling bacterial undecaprenol pyrophosphate phosphatases, PgpB, YbjB and YeiU/LpxT. The second group comprises the bacterial undecaprenol pyrophosphate phosphatase, BacA/UppP, responsible for initial formation of undecaprenyl phosphate, which we predict contains a tyrosine phosphate phosphatase motif resembling that of the tumour suppressor, phosphatase and tensin homologue (PTEN). Based on protein sequence alignments across species and 2D structure predictions, we propose catalytic and lipid recognition motifs unique to BacA/UppP enzymes. The verification of our proposed active-site residues would provide new strategies for the development of substrate-specific inhibitors which mimic both the lipid and pyrophosphate moieties, leading to the development of novel antimicrobial agents.
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Affiliation(s)
- Justin S Bickford
- Department of Neuroscience, University of Florida, Gainesville, FL 32610, USA
| | - Harry S Nick
- Department of Neuroscience, University of Florida, Gainesville, FL 32610, USA
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