1
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Hoyos-Gonzalez N, Ochoa-Leyva A, Benitez-Cardoza CG, Brieba LG, Lukaszewicz G, Trasviña-Arenas CH, Sotelo-Mundo RR. Identification of a cryptic functional apolipophorin-III domain within the Prominin-1 gene of Litopenaeus vannamei. Comp Biochem Physiol B Biochem Mol Biol 2024; 270:110928. [PMID: 38043730 DOI: 10.1016/j.cbpb.2023.110928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/26/2023] [Accepted: 11/27/2023] [Indexed: 12/05/2023]
Abstract
The Apolipophorin-III (apoLp-III) is reported as an essential protein element in lipids transport and incorporation in lepidopterans. Structurally, apoLp-III has an α-helix bundle structure composed of five α-helices. Interestingly, classic studies proposed a structural switch triggered by its interaction with lipids, where the α-helix bundle opens. Currently, the study of the apoLp-III has been limited to insects, with no homologs identified in other arthropods. By implementing a structure-based search with the Phyre2 algorithm surveying the shrimp Litopenaeus vannamei's transcriptome, we identified a putative apoLp-III in this farmed penaeid (LvApoLp-III). Unlike canonical apoLp-III, the LvApoLp-III was identified as an internal domain within the transmembrane protein Prominin-1. Structural modeling using the template-based Phyre2 and template-free AlphaFold algorithms rendered two distinct structural topologies: the α-helix bundle and a coiled-coil structure. Notably, the secondary structure composition on both models was alike, with differences in the orientation and distribution of the α-helices and hydrophobic moieties. Both models provide insights into the classical structural switch induced by lipids in apoLp-III. To corroborate structure/function inferences, we cloned the synthetic LvApoLp-III domain, overexpressed, and purified the recombinant protein. Circular dichroism measurements with the recombinant LvApoLp-III agreed with the structural models. In vitro liposome interaction demonstrated that the apoLp-III domain within the PROM1 of L.vannamei associated similarly to exchangeable apolipoproteins. Altogether, this work reports the presence of an apolipophorin-III domain in crustaceans for the first time and opens questions regarding its function and importance in lipid metabolism or the immune system.
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Affiliation(s)
- Nallely Hoyos-Gonzalez
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados (CINVESTAV), Irapuato, Guanajuato, Mexico. https://twitter.com/uga_langebio
| | - Adrian Ochoa-Leyva
- Departamento de Microbiología Molecular, Instituto de Biotecnología (IBT), Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos 62210, Mexico. https://twitter.com/ibt_unam
| | - Claudia G Benitez-Cardoza
- Laboratorio de Bioquímica y Biofísica Computacional, ENMH, Instituto Politécnico Nacional, Mexico City, Mexico. https://twitter.com/IPN_mx
| | - Luis G Brieba
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados (CINVESTAV), Irapuato, Guanajuato, Mexico. https://twitter.com/uga_langebio
| | - German Lukaszewicz
- Instituto de Investigaciones Marinas y Costeras, IIMyC, FCEyN, UNMdP, CONICET, Mar del Plata B7608FBY, Argentina. https://twitter.com/fceyn_unmdp
| | - Carlos H Trasviña-Arenas
- Centro de Investigación sobre Envejecimiento, Centro de Investigación y de Estudios Avanzados (CINVESTAV) Unidad Sede Sur, Tlalpan, 14330 Mexico City, Mexico.
| | - Rogerio R Sotelo-Mundo
- Laboratorio de Estructura Biomolecular, Centro de Investigación en Alimentación y Desarrollo, A.C., Ejido La Victoria, Hermosillo, Sonora 83304, Mexico.
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2
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Barrientos C, Squella JA, Moris S. The crystal structure of 4-(pyren-1-yl)butyl-4-nitrobenzoate, C 27H 21NO 4. Z KRIST-NEW CRYST ST 2023. [DOI: 10.1515/ncrs-2023-0034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Abstract
C27H21NO4, triclinic,
P
1
‾
$P\overline{1}$
(no. 2), a = 7.3476(2) Å, b = 7.4894(2) Å, c = 20.5137(5) Å, α = 89.33000(10)°, β = 79.7070(10)°, γ = 67.5220(10)°, V = 1024.31(5) Å3, Z = 2, R
gt
(F) = 0.0536, wR
ref
(F
2) = 0.1792, T = 296.15 K.
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Affiliation(s)
- Claudio Barrientos
- Instituto de ciencias quimicas aplicada , Facultad de Ingenieria, Universidad Autónoma de Chile , Talca , Chile
| | - Juan Arturo Squella
- Facultad de Ciencias Quimicas y Farmaceuticas , Centro de Investigacion de procesos redox (CiPRex) , Universidad de Chile , Santiago , Chile
| | - Silvana Moris
- Centro de Investigación de Estudios Avanzados del Maule (CIEAM) , Vicerrectoría de Investigación y Postgrado , Universidad Católica del Maule , Avenida San Miguel 3605 , Talca 3480112 , Chile
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3
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Design of pyrene functionalized triazole linked organosilane for specific detection of Ce3+ ions. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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4
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Kothari S, Bala N, Patel AB, Donovan A, Narayanaswami V. The LDL receptor binding domain of apolipoprotein E directs the relative orientation of its C-terminal segment in reconstituted nascent HDL. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183618. [PMID: 33831404 PMCID: PMC8211829 DOI: 10.1016/j.bbamem.2021.183618] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 03/11/2021] [Accepted: 03/22/2021] [Indexed: 12/24/2022]
Abstract
Apolipoprotein E (apoE) (299 residues) is a highly helical protein that plays a critical role in cholesterol homeostasis. It comprises a four-helix bundle N-terminal (NT) and a C-terminal (CT) domain that can exist in lipid-free and lipid-associated states. In humans, there are two major apoE isoforms, apoE3 and apoE4, which differ in a single residue in the NT domain, with apoE4 strongly increasing risk of Alzheimer's disease (AD) and cardiovascular diseases (CVD). It has been proposed that the CT domain initiates rapid lipid binding, followed by a slower NT domain helix bundle opening and lipid binding to yield discoidal reconstituted high density lipoprotein (rHDL). However, the contribution of the NT domain on the CT domain organization in HDL remains poorly understood. To understand this, we employed Cys-specific cross-linking and spatially-sensitive fluorophores in the NT and CT domains of apoE3 and apoE4, and in isolated CT domain. We noted that the helices in isolated CT domain are oriented parallel to those in the neighboring molecule in rHDL, whereas full length apoE3 and apoE4 adopt either an anti-parallel or hairpin-like organization. It appears that the bulky NT domain determines the spatial organization of its CT domain in rHDL, a finding that has significance for apoE4, which is more susceptible to proteolytic cleavage in AD brains, showing increased accumulation of neurotoxic NT and CT fragments. We envisage that the structural organization of HDL apoE would have profound functional consequences in its ability to regulate cholesterol homeostasis in AD and CVD.
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Affiliation(s)
- S Kothari
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - N Bala
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - A B Patel
- Department of Neuroscience, Novartis Institutes for BioMedical Research, Cambridge, MA 02139, USA
| | - A Donovan
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90033, USA
| | - V Narayanaswami
- Department of Chemistry and Biochemistry, 1250 Bellflower Blvd., California State University, Long Beach, Long Beach, CA 90840, USA.
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5
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Peng Y, Kelle R, Little C, Michonova E, Kornev KG, Alexov E. pH-Dependent Interactions of Apolipophorin-III with a Lipid Disk. JOURNAL OF COMPUTATIONAL BIOPHYSICS AND CHEMISTRY 2021. [DOI: 10.1142/s2737416520420041] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Apolipophorin-III (ApoLp-III) is required for stabilization of molecular shuttles of lipid fuels in insects and is found to contribute to the insect immune reaction. Rearrangement of its five [Formula: see text]-helices enables ApoLp-III to reversibly associate with lipids. We investigate computationally the conformational changes of ApoLp-III and the pH-dependence of the binding free energy of ApoLp-III association with a lipid disk. A dominant binding mode along with several minor, low population, modes of the ApoLp-III binding to a lipid disk was identified. The pH-dependence of the binding energy for ApoLp-III with the lipid disk is predicted to be significant, with the pH-optimum at pH[Formula: see text]. The calculations suggest that there are no direct interactions between the lipid head groups and titratable residues of ApoLp-III. In the physiological pH range from 6.0 to 9.0, the binding free energy of ApoLp-III with the lipid disk decreases significantly with respect to its optimal value at pH 8.0 (at pH[Formula: see text], it is 1.02[Formula: see text]kcal/mol and at pH[Formula: see text] it is 0.23[Formula: see text]kcal/mol less favorable than at the optimal pH[Formula: see text]), indicating that the pH is an important regulator of ApoLp-III lipid disk association.
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Affiliation(s)
- Yunhui Peng
- Department of Physics and Astronomy, College of Sciences, Clemson University, Clemson, SC 29634, USA
| | - Rudolfs Kelle
- Department of Physics and Astronomy, College of Sciences, Clemson University, Clemson, SC 29634, USA
- Department of Chemistry, Erskine College, Due West, SC 29639, USA
| | - Chandler Little
- Department of Physics and Astronomy, College of Sciences, Clemson University, Clemson, SC 29634, USA
- Department of Chemistry, Erskine College, Due West, SC 29639, USA
| | | | - Kostantin G. Kornev
- Department of Material Sciences and Engineering, Clemson University, Clemson, SC 29634, USA
| | - Emil Alexov
- Department of Physics and Astronomy, College of Sciences, Clemson University, Clemson, SC 29634, USA
- Department of Material Sciences and Engineering, Clemson University, Clemson, SC 29634, USA
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6
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Russell BA, Horn JV, Weers PM. Fragments of Locusta migratoria apoLp-III provide insight into lipid binding. BBA ADVANCES 2021; 1. [PMID: 36267477 PMCID: PMC9581338 DOI: 10.1016/j.bbadva.2021.100020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Apolipophorin III (apoLp-III) from Locusta migratoria is an exchangeable apolipoprotein with a critical role in lipid transport in insects. The protein is composed of a bundle of five amphipathic α-helices which undergo a large conformational change upon lipid binding. To better understand the apoLp-III lipid binding interaction, the protein was cleaved by cyanogen bromide upon introduction of a S92M mutation, generating an N-terminal fragment corresponding to the first three helices (NTH1–3) and a C-terminal fragment of the last two helices (CTH4–5). MALDI-TOF analysis of the HPLC purified fragments provided masses of 9863.8 Da for NTH1–3 and 7497.0 Da for CTH4–5 demonstrating that the intended fragments were obtained. Circular dichroism spectra revealed a decrease in helical content from 82% for the intact protein to 57% for NTH1–3 and 41% for CTH4–5. The fragments adopted considerably higher α-helical structure in the presence of trifluoroethanol or phospholipids. Equimolar mixing of the two fragments did not result in changes in helical content or tryptophan fluorescence, indicating recombination into the native protein fold did not occur. The rate of protein induced dimyristoylphosphatidylcholine vesicle solubilization increased 15-fold for NTH1–3 and 100-fold for CTH4–5 compared to the intact protein. Despite the high activity in phospholipid vesicle interaction, CTH4–5 did not protect phospholipase-treated low-density lipoprotein from aggregation. In contrast, NTH1–3 provided protection to lipoprotein aggregation similar to the intact protein, indicating that specific amino acid residues in this part of apoLp-III are essential for lipoprotein binding interaction.
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7
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Ayyavoo K, Velusamy P. Pyrene based materials as fluorescent probes in chemical and biological fields. NEW J CHEM 2021. [DOI: 10.1039/d1nj00158b] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Molecules that experience a change in their fluorescence emission due to the effect of fluorescence enhancement upon binding events, like chemical reactions or a change in their immediate environment, are regarded as fluorescent probes.
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Affiliation(s)
- Kannan Ayyavoo
- Department of Chemistry
- Bharathiar University
- Coimbatore – 641046
- India
| | - Praveena Velusamy
- Department of Chemistry
- Bharathiar University
- Coimbatore – 641046
- India
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8
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Palusińska-Szysz M, Zdybicka-Barabas A, Frąc M, Gruszecki WI, Wdowiak-Wróbel S, Reszczyńska E, Skorupska D, Mak P, Cytryńska M. Identification and characterization of Staphylococcus spp. and their susceptibility to insect apolipophorin III. Future Microbiol 2020; 15:1015-1032. [PMID: 32811181 DOI: 10.2217/fmb-2019-0328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: This study investigated the effect of an insect antimicrobial protein, apolipophorin III (apoLp-III), against two newly isolated, identified and characterized clinical strains of Staphylococcus spp. Materials & methods: Both strains were identified by 16S rRNA sequencing and metabolic and phenotypic profiling. The antibacterial activity of apoLp-III was tested using a colony counting assay. ApoLp-III interaction with bacterial cell surface was analyzed by Fourier transform IR spectroscopy. Results: Staphylococcus epidermidis and Staphylococcus capitis were identified. ApoLp-III exerted a dose-dependent bactericidal effect on the tested strains. The differences in the Staphylococcus spp. surface components may contribute to the various sensitivities of these strains to apoLp-III. Conclusion: ApoLp-III may provide a baseline for development of antibacterial preparations against Staphylococcus spp. involved in dermatological problems.
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Affiliation(s)
- Marta Palusińska-Szysz
- Department of Genetics and Microbiology, Institute of Biological Sciences, Faculty of Biology & Biotechnology, Maria Curie-Sklodowska University, Akademicka 19 St., 20-033 Lublin, Poland
| | - Agnieszka Zdybicka-Barabas
- Department of Immunobiology, Institute of Biological Sciences, Faculty of Biology & Biotechnology, Maria Curie-Sklodowska University, Akademicka 19 St., 20-033 Lublin, Poland
| | - Magdalena Frąc
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4 St., 20-290 Lublin, Poland
| | - Wiesław I Gruszecki
- Department of Biophysics, Institute of Physics, Maria Curie-Skłodowska University, Maria Curie-Skłodowska Square 1, 20-031 Lublin, Poland
| | - Sylwia Wdowiak-Wróbel
- Department of Genetics and Microbiology, Institute of Biological Sciences, Faculty of Biology & Biotechnology, Maria Curie-Sklodowska University, Akademicka 19 St., 20-033 Lublin, Poland
| | - Emilia Reszczyńska
- Department of Plant Physiology & Biophysics, Institute of Biological Sciences, Faculty of Biology & Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 St., 20-033 Lublin, Poland
| | | | - Paweł Mak
- Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics & Biotechnology, Jagiellonian University, Gronostajowa 7 St., 30-387 Krakow
| | - Małgorzata Cytryńska
- Department of Immunobiology, Institute of Biological Sciences, Faculty of Biology & Biotechnology, Maria Curie-Sklodowska University, Akademicka 19 St., 20-033 Lublin, Poland
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9
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Apolipophorin III interaction with phosphatidylglycerol and lipopolysaccharide: A potential mechanism for antimicrobial activity. Chem Phys Lipids 2020; 229:104909. [DOI: 10.1016/j.chemphyslip.2020.104909] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 03/18/2020] [Accepted: 03/18/2020] [Indexed: 01/27/2023]
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10
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Lipid-bound apoLp-III is less effective in binding to lipopolysaccharides and phosphatidylglycerol vesicles compared to the lipid-free protein. Mol Cell Biochem 2019; 458:61-70. [PMID: 31016454 DOI: 10.1007/s11010-019-03530-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 04/10/2019] [Indexed: 11/27/2022]
Abstract
Apolipophorin III (apoLp-III) is an insect apolipoprotein that is predominantly present in a lipid-free state in the hemolymph. ApoLp-III from Galleria mellonella is able to interact with membrane components of Gram-negative bacteria, as part of an innate immune response to infection. The protein also exists in a lipoprotein-associated state when large amounts of lipids are mobilized. Therefore, lipid-bound apoLp-III was generated to analyze the binding interaction with lipopolysaccharides and phosphatidylglycerol, both abundantly present in membranes of Gram-negative bacteria. G. mellonella apoLp-III was lipidated with palmitoyl-2-oleoyl-glycero-3-phosphocholine to form lipid-protein complexes. The particle shape was discoidal with a 16.4 nm diameter, a molecular mass of 460 kDa, and contained 4 apoLp-III molecules. These discoidal lipoproteins were used to compare the lipopolysaccharide and phosphatidylglycerol binding activity with lipid-free apoLp-III. Lipopolysaccharide binding interaction was analyzed by non-denaturing PAGE, showing reduced ability of the lipid-bound protein to form lipopolysaccharide-protein complexes and to disaggregate lipopolysaccharide micelles. The apoLp-III-induced release of calcein from phosphatidylglycerol vesicles was decreased approximately fivefold when the protein was in the lipid-bound form, indicating reduced binding interaction with the phosphatidylglycerol membrane surface. These results show that when apoLp-III adopts a lipid-bound conformation, it is markedly less effective in interacting with lipopolysaccharides and phosphatidylglycerol vesicles. Thus, in order to be an effective antimicrobial protein, apoLp-III needs to be in a lipid-free state.
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11
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Stączek S, Zdybicka-Barabas A, Mak P, Sowa-Jasiłek A, Kedracka-Krok S, Jankowska U, Suder P, Wydrych J, Grygorczuk K, Jakubowicz T, Cytryńska M. Studies on localization and protein ligands of Galleria mellonella apolipophorin III during immune response against different pathogens. JOURNAL OF INSECT PHYSIOLOGY 2018; 105:18-27. [PMID: 29289504 DOI: 10.1016/j.jinsphys.2017.12.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 11/28/2017] [Accepted: 12/27/2017] [Indexed: 06/07/2023]
Abstract
A lipid-binding protein apolipophorin III (apoLp-III), an exchangeable component of lipophorin particles, is involved in lipid transport and immune response in insects. In Galleria mellonella, apoLp-III binding to high-density lipophorins and formation of low-density lipophorin complexes upon immune challenge was reported. However, an unanswered question remains whether apoLp-III could form different complexes in a pathogen-dependent manner. Here we report on pathogen- and time-dependent alterations in the level of apoLp-III free and lipophorin-bound form that occur in the hemolymph and hemocytes shortly after immunization of G. mellonella larvae with different pathogens, i.e. Gram-negative bacterium Escherichia coli, Gram-positive bacterium Micrococcus luteus, yeast-like fungus Candida albicans, and filamentous fungus Fusarium oxysporum. These changes were accompanied by differently persistent re-localization of apoLp-III in the hemocytes. The apoLp-III-interacting proteins were recovered from immune hemolymph by affinity chromatography on a Sepharose bed with immobilized anti-apoLp-III antibodies. ApoLp-I, apoLp-II, hexamerin, and arylphorin were identified as main components that bound to apoLp-III; the N-terminal amino acid sequences of G. mellonella apoLp-I and apoLp-II were determined for the first time. In the recovered complexes, the pathogen-dependent differences in the content of individual apolipophorins were detected. Apolipophorins may thus be postulated as signaling molecules responding in an immunogen-dependent manner in early steps of G. mellonella immune response.
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Affiliation(s)
- Sylwia Stączek
- Department of Immunobiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 St., 20-033 Lublin, Poland
| | - Agnieszka Zdybicka-Barabas
- Department of Immunobiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 St., 20-033 Lublin, Poland
| | - Paweł Mak
- Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7 St., 30-387 Krakow, Poland; Malopolska Centre of Biotechnology, Gronostajowa 7A St., 30-387 Krakow, Poland
| | - Aneta Sowa-Jasiłek
- Department of Immunobiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 St., 20-033 Lublin, Poland
| | - Sylwia Kedracka-Krok
- Department of Physical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7 St., 30-387 Krakow, Poland; Malopolska Centre of Biotechnology, Gronostajowa 7A St., 30-387 Krakow, Poland
| | - Urszula Jankowska
- Malopolska Centre of Biotechnology, Gronostajowa 7A St., 30-387 Krakow, Poland
| | - Piotr Suder
- Biochemistry and Neurobiology Department, Faculty of Materials Science and Ceramics, AGH University of Science and Technology, Mickiewicza 30 ave., 30-059 Krakow, Poland
| | - Jerzy Wydrych
- Department of Comparative Anatomy and Anthropology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 St., 20-033 Lublin, Poland
| | - Katarzyna Grygorczuk
- Department of Immunobiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 St., 20-033 Lublin, Poland
| | - Teresa Jakubowicz
- Department of Immunobiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 St., 20-033 Lublin, Poland
| | - Małgorzata Cytryńska
- Department of Immunobiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 St., 20-033 Lublin, Poland.
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12
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Mirheydari M, Mann EK, Kooijman EE. Interaction of a model apolipoprotein, apoLp-III, with an oil-phospholipid interface. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:396-406. [PMID: 29030246 DOI: 10.1016/j.bbamem.2017.10.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 09/22/2017] [Accepted: 10/08/2017] [Indexed: 01/29/2023]
Abstract
Lipid droplets are "small" organelles that play an important role in de novo synthesis of new membrane, and steroid hormones, as well as in energy storage. The way proteins interact specifically with the oil-(phospho-)lipid monolayer interface of lipid droplets is a relatively unexplored but crucial question. Here, we use our home built liquid droplet tensiometer to mimic intracellular lipid droplets and study protein-lipid interactions at this interface. As model neutral lipid binding protein, we use apoLp-III, an amphipathic α-helix bundle protein. This domain is also found in proteins from the perilipin family and in apoE. Protein binding to the monolayer is studied by the decrease in the oil/water surface tension. Previous work used POPC (one of the major lipids found on lipid droplets) to form the phospholipid monolayer on the triolein surface. Here we expand this work by incorporating other lipids with different physico-chemical properties to study the effect of charge and lipid head-group size. This study sheds light on the affinity of this important protein domain to interact with lipids.
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Affiliation(s)
- Mona Mirheydari
- Physics Department, Kent State University, Kent, OH 44242, United States.
| | - Elizabeth K Mann
- Physics Department, Kent State University, Kent, OH 44242, United States
| | - Edgar E Kooijman
- Department of Biological Sciences, Kent State University, Kent, OH 44242, United States
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13
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Khalifa NM, Al-Omar MA, Ali OM. Synthesis and reactions of some new (E)-2-сyano-N′-[1-(pyren-3-yl)ethylidene]acetohydrazide derivatives. RUSS J GEN CHEM+ 2017. [DOI: 10.1134/s1070363217090250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Altwaijry NA, Baron M, Wright DW, Coveney PV, Townsend-Nicholson A. An Ensemble-Based Protocol for the Computational Prediction of Helix-Helix Interactions in G Protein-Coupled Receptors using Coarse-Grained Molecular Dynamics. J Chem Theory Comput 2017; 13:2254-2270. [PMID: 28383913 PMCID: PMC5557214 DOI: 10.1021/acs.jctc.6b01246] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
![]()
The
accurate identification of the specific points of interaction
between G protein-coupled receptor (GPCR) oligomers is essential for
the design of receptor ligands targeting oligomeric receptor targets.
A coarse-grained molecular dynamics computer simulation approach would
provide a compelling means of identifying these specific protein–protein
interactions and could be applied both for known oligomers of interest
and as a high-throughput screen to identify novel oligomeric targets.
However, to be effective, this in silico modeling must provide accurate,
precise, and reproducible information. This has been achieved recently
in numerous biological systems using an ensemble-based all-atom molecular
dynamics approach. In this study, we describe an equivalent methodology
for ensemble-based coarse-grained simulations. We report the performance
of this method when applied to four different GPCRs known to oligomerize
using error analysis to determine the ensemble size and individual
replica simulation time required. Our measurements of distance between
residues shown to be involved in oligomerization of the fifth transmembrane
domain from the adenosine A2A receptor are in very good
agreement with the existing biophysical data and provide information
about the nature of the contact interface that cannot be determined
experimentally. Calculations of distance between rhodopsin, CXCR4,
and β1AR transmembrane domains reported to form contact
points in homodimers correlate well with the corresponding measurements
obtained from experimental structural data, providing an ability to predict
contact interfaces computationally. Interestingly, error analysis
enables identification of noninteracting regions. Our results confirm
that GPCR interactions can be reliably predicted using this novel
methodology.
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Affiliation(s)
- Nojood A Altwaijry
- Institute of Structural and Molecular Biology, Research Department of Structural and Molecular Biology, Division of Biosciences, University College London , London, WC1E 6BT, United Kingdom.,King Saud University , Riyadh, Kingdom of Saudi Arabia
| | - Michael Baron
- Institute of Structural and Molecular Biology, Research Department of Structural and Molecular Biology, Division of Biosciences, University College London , London, WC1E 6BT, United Kingdom
| | - David W Wright
- Centre for Computational Science, Department of Chemistry, University College London , London WC1H 0AJ, United Kingdom
| | - Peter V Coveney
- Centre for Computational Science, Department of Chemistry, University College London , London WC1H 0AJ, United Kingdom
| | - Andrea Townsend-Nicholson
- Institute of Structural and Molecular Biology, Research Department of Structural and Molecular Biology, Division of Biosciences, University College London , London, WC1E 6BT, United Kingdom
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15
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Wen D, Wang X, Shang L, Huang Y, Li T, Wu C, Zhang R, Zhang J. Involvement of a versatile pattern recognition receptor, apolipophorin-III in prophenoloxidase activation and antibacterial defense of the Chinese oak silkworm, Antheraea pernyi. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2016; 65:124-131. [PMID: 27387151 DOI: 10.1016/j.dci.2016.07.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 06/30/2016] [Accepted: 07/01/2016] [Indexed: 06/06/2023]
Abstract
Apolipophorin-III (apoLp-III) is an exchangeable apolipoprotein found in many insect species and functions as a lipid transport vehicle. Recent studies have shown that apoLp-III is a multifunctional molecule involved in not only lipid transportation but also innate immune responses. In the present study, the pattern recognition properties of Antheraea pernyi apoLp-III were investigated. Recombinant Ap-apoLp-III was bound to different species of microbes and further study showed the rAp-apoLp-III is capable of interacting with pathogen associated molecular patterns (PAMPs) on the microbial cell surface. In addition, an Ap-apoLp-III/PAMP mixture stimulated the prophenoloxidase (PPO) activation of A. pernyi hemolymph in vitro, to a greater extent than PAMP alone while Ap-apoLp-III itself failed to activate the PPO system, indicating that Ap-apoLp-III up-regulates PPO activation by combining with PAMP. After pathogen invasion following an injection of Staphylococcus aureus, RNAi-mediated silencing of apoLp-III decreased the transcriptional abundance of three antimicrobial peptide genes. These data suggest that apoLp-III is a versatile pattern recognition receptor and may play important roles in the innate immune responses of Antheraea pernyi.
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Affiliation(s)
- Daihua Wen
- School of Life Science and Bio-pharmaceutics, Shenyang Pharmaceutical University, China
| | - Xialu Wang
- School of Medical Devices, Shenyang Pharmaceutical University, China
| | - Lei Shang
- School of Pharmacy, China Medical University, China
| | - Yu Huang
- School of Life Science and Bio-pharmaceutics, Shenyang Pharmaceutical University, China
| | - Tienan Li
- School of Life Science and Bio-pharmaceutics, Shenyang Pharmaceutical University, China
| | - Chunfu Wu
- School of Life Science and Bio-pharmaceutics, Shenyang Pharmaceutical University, China
| | - Rong Zhang
- School of Life Science and Bio-pharmaceutics, Shenyang Pharmaceutical University, China
| | - Jinghai Zhang
- School of Medical Devices, Shenyang Pharmaceutical University, China.
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16
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Dwivedi P, Rodriguez J, Ibe NU, Weers PMM. Deletion of the N- or C-Terminal Helix of Apolipophorin III To Create a Four-Helix Bundle Protein. Biochemistry 2016; 55:3607-15. [PMID: 27280697 DOI: 10.1021/acs.biochem.6b00381] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Apolipophorin III (apoLp-III) is an exchangeable apolipoprotein found in insects and plays an important function in lipid transport. The protein has an unusual five-helix bundle architecture, deviating from the common four-helix bundle motif. To understand the role of the additional helix in apoLp-III, the N-terminal or C-terminal helix was deleted to create a putative four-helix bundle protein. While the protein lacking helix-1 could be expressed in bacteria albeit at reduced yields, apoLp-III lacking helix-5 could not be produced. Mutational analysis by truncating helix-5 showed that a minimum segment of approximately one-third of the C-terminal helix is required for protein expression. The variant lacking helix-5 was produced by inserting a methionine residue between helix-4 and -5; subsequent cyanogenbromide cleavage generated the four-helix variant. Both N- and C-terminal helix deletion variants displayed significantly reduced helical content, protein stability, and tertiary structure. Despite the significantly altered structure, the variants were still fully functional. The rate of dimyristoylphosphatidylcholine vesicle solubilization was enhanced 4-5-fold compared to the wild-type protein, and the deletion variants were effective in binding to lipolyzed low density lipoprotein thereby preventing lipoprotein aggregation. These results show that the additional helix of apoLp-III is not essential for lipid binding but is required for proper folding to keep the protein into a stable conformation.
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Affiliation(s)
- Pankaj Dwivedi
- Department of Chemistry and Biochemistry, California State University , Long Beach, California 90840, United States
| | - Johana Rodriguez
- Department of Chemistry and Biochemistry, California State University , Long Beach, California 90840, United States
| | - Nnejiuwa U Ibe
- Department of Chemistry and Biochemistry, California State University , Long Beach, California 90840, United States
| | - Paul M M Weers
- Department of Chemistry and Biochemistry, California State University , Long Beach, California 90840, United States
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17
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Palusińska-Szysz M, Zdybicka-Barabas A, Reszczyńska E, Luchowski R, Kania M, Gisch N, Waldow F, Mak P, Danikiewicz W, Gruszecki WI, Cytryńska M. The lipid composition of Legionella dumoffii membrane modulates the interaction with Galleria mellonella apolipophorin III. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:617-29. [PMID: 27094351 DOI: 10.1016/j.bbalip.2016.04.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 04/11/2016] [Accepted: 04/15/2016] [Indexed: 11/26/2022]
Abstract
Apolipophorin III (apoLp-III), an insect homologue of human apolipoprotein E (apoE), is a widely used model protein in studies on protein-lipid interactions, and anti-Legionella activity of Galleria mellonella apoLp-III has been documented. Interestingly, exogenous choline-cultured Legionella dumoffii cells are considerably more susceptible to apoLp-III than non-supplemented bacteria. In order to explain these differences, we performed, for the first time, a detailed analysis of L. dumoffii lipids and a comparative lipidomic analysis of membranes of bacteria grown without and in the presence of exogenous choline. (31)P NMR analysis of L. dumoffii phospholipids (PLs) revealed a considerable increase in the phosphatidylcholine (PC) content in bacteria cultured on choline medium and a decrease in the phosphatidylethanolamine (PE) content in approximately the same range. The interactions of G. mellonella apoLp-III with lipid bilayer membranes prepared from PLs extracted from non- and choline-supplemented L. dumoffii cells were examined in detail by means of attenuated total reflection- and linear dichroism-Fourier transform infrared spectroscopy. Furthermore, the kinetics of apoLp-III binding to liposomes formed from L. dumoffii PLs was analysed by fluorescence correlation spectroscopy and fluorescence lifetime imaging microscopy using fluorescently labelled G. mellonella apoLp-III. Our results indicated enhanced binding of apoLp-III to and deeper penetration into lipid membranes formed from PLs extracted from the choline-supplemented bacteria, i.e. characterized by an increased PC/PE ratio. This could explain, at least in part, the higher susceptibility of choline-cultured L. dumoffii to G. mellonella apoLp-III.
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Affiliation(s)
- Marta Palusińska-Szysz
- Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033 Lublin, Poland.
| | - Agnieszka Zdybicka-Barabas
- Department of Immunobiology, Institute of Biology and Biochemistry, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033 Lublin, Poland.
| | - Emilia Reszczyńska
- Department of Biophysics, Institute of Physics, Maria Curie-Sklodowska University, Maria Curie-Sklodowska Square 1, 20-031 Lublin, Poland; Department of Biophysics, Institute of Biology and Biochemistry, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033 Lublin, Poland.
| | - Rafał Luchowski
- Department of Biophysics, Institute of Physics, Maria Curie-Sklodowska University, Maria Curie-Sklodowska Square 1, 20-031 Lublin, Poland.
| | - Magdalena Kania
- Mass Spectrometry Group, Institute of Organic Chemistry Polish Academy of Sciences, Kasprzaka 44/52 St., 01-224 Warsaw, Poland.
| | - Nicolas Gisch
- Division of Bioanalytical Chemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 1-40, 23845 Borstel, Germany.
| | - Franziska Waldow
- Division of Bioanalytical Chemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 1-40, 23845 Borstel, Germany.
| | - Paweł Mak
- Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7 St., 30-387 Krakow; Malopolska Centre of Biotechnology, Gronostajowa 7A St., 30-387 Krakow, Poland.
| | - Witold Danikiewicz
- Mass Spectrometry Group, Institute of Organic Chemistry Polish Academy of Sciences, Kasprzaka 44/52 St., 01-224 Warsaw, Poland.
| | - Wiesław I Gruszecki
- Department of Biophysics, Institute of Physics, Maria Curie-Sklodowska University, Maria Curie-Sklodowska Square 1, 20-031 Lublin, Poland.
| | - Małgorzata Cytryńska
- Department of Immunobiology, Institute of Biology and Biochemistry, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033 Lublin, Poland.
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18
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Khalifa NM, Nossier ES, Al-Omar MA, Amr AE. Synthesis of some novel S-alkylated and S-glycosylated hydantoin derivatives containing pyrene moiety. RUSS J GEN CHEM+ 2016. [DOI: 10.1134/s1070363216040277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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19
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Van der Horst DJ, Rodenburg KW. Lipoprotein assembly and function in an evolutionary perspective. Biomol Concepts 2015; 1:165-83. [PMID: 25961995 DOI: 10.1515/bmc.2010.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Circulatory fat transport in animals relies on members of the large lipid transfer protein (LLTP) superfamily, including mammalian apolipoprotein B (apoB) and insect apolipophorin II/I (apoLp-II/I). ApoB and apoLp-II/I, constituting the structural (non-exchangeable) basis for the assembly of various lipoproteins, acquire lipids through microsomal triglyceride-transfer protein, another LLTP family member, and bind them by means of amphipathic α-helical and β-sheet structural motifs. Comparative research reveals that LLTPs evolved from the earliest animals and highlights the structural adaptations in these lipid-binding proteins. Thus, in contrast to apoB, apoLp-II/I is cleaved post-translationally by a furin, resulting in the appearance of two non-exchangeable apolipoproteins in the single circulatory lipoprotein in insects, high-density lipophorin (HDLp). The remarkable structural similarities between mammalian and insect lipoproteins notwithstanding important functional differences relate to the mechanism of lipid delivery. Whereas in mammals, partial delipidation of apoB-containing lipoproteins eventually results in endocytic uptake of their remnants, mediated by members of the low-density lipoprotein receptor (LDLR) family, and degradation in lysosomes, insect HDLp functions as a reusable lipid shuttle capable of alternate unloading and reloading of lipid. Also, during muscular efforts (flight activity), an HDLp-based lipoprotein shuttle provides for the transport of lipid for energy generation. Although a lipophorin receptor - a homolog of LDLR - was identified that mediates endocytic uptake of HDLp during specific developmental periods, the endocytosed lipoprotein appears to be recycled in a transferrin-like manner. These data highlight that the functional adaptations in the lipoprotein lipid carriers in mammals and insects also emerge with regard to the functioning of their cognate receptors.
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20
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Liu QN, Lin KZ, Yang LN, Dai LS, Wang L, Sun Y, Qian C, Wei GQ, Liu DR, Zhu BJ, Liu CL. Molecular characterization of an Apolipophorin-III gene from the Chinese oak silkworm, Antheraea pernyi (Lepidoptera: Saturniidae). ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2015; 88:155-167. [PMID: 25348706 DOI: 10.1002/arch.21210] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Apolipophorin-III (ApoLp-III) acts in lipid transport, lipoprotein metabolism, and innate immunity in insects. In this study, an ApoLp-III gene of Antheraea pernyi pupae (Ap-ApoLp-III) was isolated and characterized. The full-length cDNA of Ap-ApoLp-III is 687 bp, including a 5'-untranslated region (UTR) of 40 bp, 3'-UTR of 86 bp and an open reading frame of 561 bp encoding a polypeptide of 186 amino acids that contains an Apolipophorin-III precursor domain (PF07464). The deduced Ap-apoLp-III protein sequence has 68, 59, and 23% identity with its orthologs of Manduca sexta, Bombyx mori, and Aedes aegypti, respectively. Phylogenetic analysis showed that the Ap-apoLp-III was close to that of Bombycoidea. qPCR analysis revealed that Ap-ApoLp-III expressed during the four developmental stages and in integument, fat body, and ovaries. After six types of microorganism infections, expression levels of the Ap-ApoLp-III gene were upregulated significantly at different time points compared with control. RNA interference (RNAi) of Ap-ApoLp-III showed that the expression of Ap-ApoLp-III was significantly downregulated using qPCR after injection of E. coli. We infer that the Ap-ApoLp-III gene acts in the innate immunity of A. pernyi.
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Affiliation(s)
- Qiu-Ning Liu
- College of Life Sciences, Anhui Agricultural University, Hefei, P. R.China
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21
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Galleria mellonella apolipophorin III – an apolipoprotein with anti-Legionella pneumophila activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2689-97. [DOI: 10.1016/j.bbamem.2014.07.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 06/23/2014] [Accepted: 07/01/2014] [Indexed: 12/19/2022]
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22
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Synthesis, characterization and pharmacological investigations of some novel heterocyclic derivatives incorporating pyrene and sugar moieties. RESEARCH ON CHEMICAL INTERMEDIATES 2014. [DOI: 10.1007/s11164-013-1061-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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23
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Noh JY, Patnaik BB, Tindwa H, Seo GW, Kim DH, Patnaik HH, Jo YH, Lee YS, Lee BL, Kim NJ, Han YS. Genomic organization, sequence characterization and expression analysis of Tenebrio molitor apolipophorin-III in response to an intracellular pathogen, Listeria monocytogenes. Gene 2013; 534:204-17. [PMID: 24200961 DOI: 10.1016/j.gene.2013.10.058] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 10/21/2013] [Accepted: 10/26/2013] [Indexed: 11/29/2022]
Abstract
Apolipophorin III (apoLp-III) is a well-known hemolymph protein having a functional role in lipid transport and immune response of insects. We cloned full-length cDNA encoding putative apoLp-III from larvae of the coleopteran beetle, Tenebrio molitor (TmapoLp-III), by identification of clones corresponding to the partial sequence of TmapoLp-III, subsequently followed with full length sequencing by a clone-by-clone primer walking method. The complete cDNA consists of 890 nucleotides, including an ORF encoding 196 amino acid residues. Excluding a putative signal peptide of the first 20 amino acid residues, the 176-residue mature apoLp-III has a calculated molecular mass of 19,146Da. Genomic sequence analysis with respect to its cDNA showed that TmapoLp-III was organized into four exons interrupted by three introns. Several immune-related transcription factor binding sites were discovered in the putative 5'-flanking region. BLAST and phylogenetic analyses reveal that TmapoLp-III has high sequence identity (88%) with Tribolium castaneum apoLp-III but shares little sequence homologies (<26%) with other apoLp-IIIs. Homology modeling of Tm apoLp-III shows a bundle of five amphipathic alpha helices, including a short helix 3'. The 'helix-short helix-helix' motif was predicted to be implicated in lipid binding interactions, through reversible conformational changes and accommodating the hydrophobic residues to the exterior for stability. Highest level of TmapoLp-III mRNA was detected at late pupal stages, albeit it is expressed in the larval and adult stages at lower levels. The tissue specific expression of the transcripts showed significantly higher numbers in larval fat body and adult integument. In addition, TmapoLp-III mRNA was found to be highly upregulated in late stages of L. monocytogenes or E. coli challenge. These results indicate that TmapoLp-III may play an important role in innate immune responses against bacterial pathogens in T. molitor.
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Affiliation(s)
- Ju Young Noh
- Division of Plant Biotechnology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Bharat Bhusan Patnaik
- Division of Plant Biotechnology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Hamisi Tindwa
- Division of Plant Biotechnology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Gi Won Seo
- Division of Plant Biotechnology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Dong Hyun Kim
- Division of Plant Biotechnology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Hongray Howrelia Patnaik
- Division of Plant Biotechnology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Yong Hun Jo
- Division of Plant Biotechnology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Yong Seok Lee
- Department of Life Science and Biotechnology, College of Natural Sciences, Soonchunhyang University, Asan City 336-745 Republic of Korea
| | - Bok Luel Lee
- National Research Laboratory of Defense Proteins, College of Pharmacy, Pusan National University, Jangjeon Dong, Kumjeong Ku, Busan, 609-735, Republic of Korea
| | - Nam Jung Kim
- Division of Applied Entomology, National Academy of Agricultural Science, Rural Development, 61th, Seodun-dong, Gwonseon-gu, Suwon, Gyeonggi-do, 441-853, Republic of Korea
| | - Yeon Soo Han
- Division of Plant Biotechnology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Republic of Korea.
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24
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Hanlon AD, Milosavljevic BH. Appropriate excitation wavelength removes obfuscations from pyrene excimer kinetics and mechanism studies. Photochem Photobiol Sci 2013; 12:787-97. [DOI: 10.1039/c2pp25307k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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25
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Khalifa NM, Al-Omar MA, Amr AEGE, Haiba ME. HIV-1 and HSV-1 virus activities of some new polycyclic nucleoside pyrene candidates. Int J Biol Macromol 2012. [PMID: 23178400 DOI: 10.1016/j.ijbiomac.2012.11.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In continuation of our previous work, a novel series of polycyclic derivatives 2-8 incorporated heterocyclic and sugar moieties were synthesized by using pyren-1-aldehyde (1) as starting material and their tested as antiviral activities. Initially, the toxicity of the compounds was assayed via the determination of their EC(50). Some of the synthesized compounds were tested as antiviral activity against HIV-1 and HSV-1. The structure of the new compounds was confirmed by using chemical and spectroscopic evidences. The detailed of synthesis, spectroscopic data, antiviral activities of the synthesized compounds were reported.
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Affiliation(s)
- Nagy M Khalifa
- Pharmaceutical Chemistry Department, Drug Exploration & Development Chair, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.
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26
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Bains GK, Kim SH, Sorin EJ, Narayanaswami V. The extent of pyrene excimer fluorescence emission is a reflector of distance and flexibility: analysis of the segment linking the LDL receptor-binding and tetramerization domains of apolipoprotein E3. Biochemistry 2012; 51:6207-19. [PMID: 22779734 DOI: 10.1021/bi3005285] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pyrene is a spatially sensitive probe that displays an ensemble of monomeric fluorescence emission peaks (375-405 nm) and an additional band (called excimer) at ~460 nm when two fluorophores are spatially proximal. We examined if there is a correlation between distance between two pyrenes on an α-helical structure and excimer/monomer (e/m) ratio. Using structure-guided design, pyrene maleimide was attached to pairs of Cys residues separated by ~5 Å increments on helix 2 of the N-terminal domain of apolipoprotein E3 (apoE3). Fluorescence spectral analysis revealed an intense excimer band when the probes were ~5 Å from each other with an e/m ratio of ~3.0, which decreased to ~1.0 at 20 Å. An inverse correlation between e/m ratio and the distance between pyrenes was observed, with the probe and helix flexibility also contributing to the extent of excimer formation. We verified this approach by estimating the distance between T57C and C112 (located on helices 2 and 3, respectively) to be 5.2 Å (4.9 Å from NMR and 5.7 Å from the X-ray structure). Excimer formation was also noted to a significant extent with probes located in the linker segment, suggesting spatial proximity (10-15 Å) to corresponding sites on neighboring molecules in the tetrameric configuration of apoE. We infer that oligomerization via the C-terminal domain juxtaposes the linker segments from neighboring apoE molecules. This study offers new insights into the conformation of tetrameric apoE and presents the use of pyrene as a powerful probe for studying protein spatial organization.
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Affiliation(s)
- Gursharan K Bains
- Department of Chemistry and Biochemistry, 1250 Bellflower Boulevard, California State University Long Beach, Long Beach, CA 90840, USA
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27
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Zamarreño F, Herrera FE, Córsico B, Costabel MD. Similar structures but different mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:1691-7. [DOI: 10.1016/j.bbamem.2012.03.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/27/2012] [Accepted: 03/07/2012] [Indexed: 10/28/2022]
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28
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Lee YO, Pradhan T, No K, Kim JS. N,N-Dimethylaniline and 1-(trifluoromethyl)benzene-functionalized tetrakis(ethynyl)pyrenes: synthesis, photophysical, electrochemical and computational studies. Tetrahedron 2012. [DOI: 10.1016/j.tet.2011.12.066] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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29
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Thévenin D, Lazarova T. Identifying and measuring transmembrane helix-helix interactions by FRET. Methods Mol Biol 2012; 914:87-106. [PMID: 22976024 DOI: 10.1007/978-1-62703-023-6_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Specific interactions between helical transmembrane domains (TMs) play essential roles in the mechanisms governing the folding, stability and assembly of integral membrane proteins. Thus, it is appealing to identify helix-helix contacts and to seek the structural determinants of such interactions at the molecular level. Here, we provide a protocol for detecting and measuring specific helix-helix interactions in liposomes by Förster resonance energy transfer (FRET), using peptides corresponding to the TM domains of an integral membrane protein. We give a detailed procedure and practical guidelines on how to design, prepare, handle, and characterize fluorescently labeled TM peptides reconstituted in large unilamellar lipid vesicles. We also discuss some critical aspects of FRET measurements to ensure the correct analysis and interpretation of spectral data. Our method uses tryptophan/pyrene as the donor-acceptor FRET pair, but it can be easily adapted to other fluorescence pairs and to other membrane mimetic environments. The ability to identify crucial interhelical contacts is a valuable tool for the study of the stability, assembly, and function of the important and experimentally challenging helical membrane proteins.
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Affiliation(s)
- Damien Thévenin
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
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30
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Bains G, Patel AB, Narayanaswami V. Pyrene: a probe to study protein conformation and conformational changes. Molecules 2011; 16:7909-35. [PMID: 22143550 PMCID: PMC6264589 DOI: 10.3390/molecules16097909] [Citation(s) in RCA: 190] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 09/04/2011] [Accepted: 09/06/2011] [Indexed: 11/18/2022] Open
Abstract
The review focuses on the unique spectral features of pyrene that can be utilized to investigate protein structure and conformation. Pyrene is a fluorescent probe that can be attached covalently to protein side chains, such as sulfhydryl groups. The spectral features of pyrene are exquisitely sensitive to the microenvironment of the probe: it exhibits an ensemble of monomer fluorescence emission peaks that report on the polarity of the probe microenvironment, and an additional band at longer wavelengths, the appearance of which reflects the presence of another pyrene molecule in spatial proximity (~10 Å). Its high extinction coefficient allows us to study labeled proteins in solution at physiologically relevant concentrations. The environmentally- and spatially-sensitive features of pyrene allow monitoring protein conformation, conformational changes, protein folding and unfolding, protein-protein, protein-lipid and protein-membrane interactions.
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Affiliation(s)
- Gursharan Bains
- Department of Chemistry and Biochemistry, 1250 Bellflower Boulevard, California State University Long Beach, Long Beach, CA 90840, USA
| | - Arti B. Patel
- Department of Chemistry and Biochemistry, 1250 Bellflower Boulevard, California State University Long Beach, Long Beach, CA 90840, USA
| | - Vasanthy Narayanaswami
- Department of Chemistry and Biochemistry, 1250 Bellflower Boulevard, California State University Long Beach, Long Beach, CA 90840, USA
- Children’s Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-562-985-4953; Fax: +1-562-985-8557
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Affiliation(s)
| | - Klaus Müllen
- Max Planck Institute for Polymer Research, Ackermannweg 10, P.O. Box 3148, Mainz, Germany
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Wan CPL, Chiu MH, Wu X, Lee SK, Prenner EJ, Weers PMM. Apolipoprotein-induced conversion of phosphatidylcholine bilayer vesicles into nanodisks. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1808:606-13. [PMID: 21111706 DOI: 10.1016/j.bbamem.2010.11.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 11/03/2010] [Accepted: 11/15/2010] [Indexed: 11/27/2022]
Abstract
Apolipoprotein mediated formation of nanodisks was studied in detail using apolipophorin III (apoLp-III), thereby providing insight in apolipoprotein-lipid binding interactions. The spontaneous solubilization of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) vesicles occured only in a very narrow temperature range at the gel-liquid-crystalline phase transition temperature, exhibiting a net exothermic interaction based on isothermal titration calorimetry analysis. The resulting nanodisks were protected from proteolysis by trypsin, endoproteinase Glu-C, chymotrypsin and elastase. DMPC solubilization and the simultaneous formation of nanodisks were promoted by increasing the vesicle diameter, protein to lipid ratio and concentration. Inclusion of cholesterol in DMPC dramatically enhanced the rate of nanodisk formation, presumably by stabilization of lattice defects which form the main insertion sites for apolipoprotein α-helices. The presence of fully saturated acyl chains with a length of 13 or 14 carbons in phosphatidylcholine allowed the spontaneous vesicle solubilization upon apolipoprotein addition. Nanodisks with C13:0-phosphatidylcholine were significantly smaller with a diameter of 11.7 ± 3.1nm compared to 18.5 ± 5.6 nm for DMPC nanodisks determined by transmission electron microscopy. Nanodisk formation was not observed when the phosphatidylcholine vesicles contained acyl chains of 15 or 16 carbons. However, using very high concentrations of lipid and protein (>10mg/ml), 1,2,-dipalmitoyl-sn-glycero-3-phosphocholine nanodisks could be produced spontaneously although the efficiency remained low.
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Affiliation(s)
- Chung-Ping Leon Wan
- Department of Chemistry and Biochemistry, California State University Long Beach, 1250 Bellflower Blvd., Long Beach, CA 90840, USA
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33
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Gupta L, Noh JY, Jo YH, Oh SH, Kumar S, Noh MY, Lee YS, Cha SJ, Seo SJ, Kim I, Han YS, Barillas-Mury C. Apolipophorin-III mediates antiplasmodial epithelial responses in Anopheles gambiae (G3) mosquitoes. PLoS One 2010; 5:e15410. [PMID: 21072214 PMCID: PMC2970580 DOI: 10.1371/journal.pone.0015410] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 09/06/2010] [Indexed: 11/18/2022] Open
Abstract
Background Apolipophorin-III (ApoLp-III) is known to play an important role in lipid transport and innate immunity in lepidopteran insects. However, there is no evidence of involvement of ApoLp-IIIs in the immune responses of dipteran insects such as Drosophila and mosquitoes. Methodology/Principal Findings We report the molecular and functional characterization of An. gambiae apolipophorin-III (AgApoLp-III). Mosquito ApoLp-IIIs have diverged extensively from those of lepidopteran insects; however, the predicted tertiary structure of AgApoLp-III is similar to that of Manduca sexta (tobacco hornworm). We found that AgApoLp-III mRNA expression is strongly induced in the midgut of An. gambiae (G3 strain) mosquitoes in response to Plasmodium berghei infection. Furthermore, immunofluorescence stainings revealed that high levels of AgApoLp-III protein accumulate in the cytoplasm of Plasmodium-invaded cells and AgApoLp-III silencing increases the intensity of P. berghei infection by five fold. Conclusion There are broad differences in the midgut epithelial responses to Plasmodium invasion between An. gambiae strains. In the G3 strain of An. gambiae AgApoLp-III participates in midgut epithelial defense responses that limit Plasmodium infection.
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Affiliation(s)
- Lalita Gupta
- Mosquito Immunity and Vector Competence Unit, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Ju Young Noh
- Department of Agricultural Biology, College of Agriculture and Life Science, Chonnam National University, Gwangju, South Korea
| | - Yong Hun Jo
- Department of Agricultural Biology, College of Agriculture and Life Science, Chonnam National University, Gwangju, South Korea
| | - Seung Han Oh
- Department of Agricultural Biology, College of Agriculture and Life Science, Chonnam National University, Gwangju, South Korea
| | - Sanjeev Kumar
- Mosquito Immunity and Vector Competence Unit, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Mi Young Noh
- Department of Agricultural Biology, College of Agriculture and Life Science, Chonnam National University, Gwangju, South Korea
| | - Yong Seok Lee
- Department of Parasitology, College of Medicine and Frontier Inje Research for Science and Technology, Inje University, Busan, Korea
| | - Sung-Jae Cha
- Johns Hopkins School of Public Health, Department of Molecular Microbiology and Immunology and Malaria Research Institute, Baltimore, Maryland, United States of America
| | - Sook Jae Seo
- Division of Applied Life Science, Gyeongsang National University, Jinju, Korea
| | - Iksoo Kim
- Department of Agricultural Biology, College of Agriculture and Life Science, Chonnam National University, Gwangju, South Korea
| | - Yeon Soo Han
- Department of Agricultural Biology, College of Agriculture and Life Science, Chonnam National University, Gwangju, South Korea
- * E-mail: (YSH); (CB-M)
| | - Carolina Barillas-Mury
- Mosquito Immunity and Vector Competence Unit, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
- * E-mail: (YSH); (CB-M)
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Patel AB, Khumsupan P, Narayanaswami V. Pyrene fluorescence analysis offers new insights into the conformation of the lipoprotein-binding domain of human apolipoprotein E. Biochemistry 2010; 49:1766-75. [PMID: 20073510 DOI: 10.1021/bi901902e] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The C-terminal domain (CT) of apolipoprotein E (apoE), a critical protein involved in cholesterol transport in the plasma and brain, plays an important role in high-affinity lipoprotein binding. Although high-resolution structural information is available for the N-terminal domain of apoE, the structural organization of the CT (residues 201-299) is largely unknown. In this study, we employ site-specific fluorescence labeling with pyrene maleimide to gain insight into the structure and conformation of apoE CT in its naturally self-associated state in buffer at physiologically relevant concentrations (5-50 microg/mL). Pyrene is a highly sensitive fluorophore that reports on spatial proximity between desired sites by displaying unique spectral features. Pyrene was covalently attached to single cysteine-containing recombinant human apoE CT at position 223 or 255 to probe the first predicted helical segment and at position 277 to monitor the terminal predicted helical segment. Regardless of the location of the probe, all three pyrene-labeled apoE CT variants display an intense and dramatic fluorescence excimer band at 460 nm, a signature feature of pyrene, which indicates that two pyrene moieties are within 10 A of each other. In addition, an intense peak at 387 nm (indicative of a highly hydrophobic environment) was noted in all cases. Fluorescence emission quenching by potassium iodide indicates that the accessibility to the probes was restricted at these locations. The possibility that the hydrophobicity of the pyrene moiety was the driving force for helix-helix interaction was excluded because pyrene located at position 209, which is predicted to be located in a nonhelical segment, did not display the above intense unique features. Lastly, denaturation studies suggest that the terminal helix unfolds prior to the first predicted helix in apoE CT. Our studies indicate that there are extensive intermolecular helix-helix contacts throughout the entire CT in the lipid-free state with two apoE CT molecules oriented parallel to each other to form a dimer, which dimerizes further to yield a tetramer. Such an organization allows helix-helix interactions to be replaced by helix-lipid interactions upon encountering a lipoprotein surface, with the terminal helix likely initiating the binding interaction. This study presents the possibility of employing pyrene fluorophores as powerful new alternatives to obtain conformational information of proteins at physiologically relevant concentrations.
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Affiliation(s)
- Arti B Patel
- Department of Chemistry and Biochemistry, 1250 Bellflower Boulevard, California State University Long Beach, Long Beach, California 90840, USA
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35
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Narayanaswami V, Kiss RS, Weers PMM. The helix bundle: a reversible lipid binding motif. Comp Biochem Physiol A Mol Integr Physiol 2009; 155:123-33. [PMID: 19770066 DOI: 10.1016/j.cbpa.2009.09.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 09/09/2009] [Accepted: 09/11/2009] [Indexed: 01/01/2023]
Abstract
Apolipoproteins are the protein components of lipoproteins that have the innate ability to inter convert between a lipid-free and a lipid-bound form in a facile manner, a remarkable property conferred by the helix bundle motif. Composed of a series of four or five amphipathic alpha-helices that fold to form a helix bundle, this motif allows the en face orientation of the hydrophobic faces of the alpha-helices in the protein interior in the lipid-free state. A conformational switch then permits helix-helix interactions to be substituted by helix-lipid interactions upon lipid binding interaction. This review compares the apolipoprotein high-resolution structures and the factors that trigger this switch in insect apolipophorin III and the mammalian apolipoproteins, apolipoprotein E and apolipoprotein A-I, pointing out the commonalities and key differences in the mode of lipid interaction. Further insights into the lipid-bound conformation of apolipoproteins are required to fully understand their functional role under physiological conditions.
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Affiliation(s)
- Vasanthy Narayanaswami
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach CA 90840, USA
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36
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Apolipophorin III interaction with model membranes composed of phosphatidylcholine and sphingomyelin using differential scanning calorimetry. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:2160-8. [PMID: 19647717 DOI: 10.1016/j.bbamem.2009.07.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 07/14/2009] [Accepted: 07/24/2009] [Indexed: 01/09/2023]
Abstract
Apolipophorin III (apoLp-III) from Locusta migratoria was employed as a model apolipoprotein to gain insight into binding interactions with lipid vesicles. Differential scanning calorimetry (DSC) was used to measure the binding interaction of apoLp-III with liposomes composed of mixtures of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and sphingomyelin (SM). Association of apoLp-III with multilamellar liposomes occurred over a temperature range around the liquid crystalline phase transition (L(alpha)). Qualitative and quantitative data were obtained from changes in the lipid phase transition upon addition of apoLp-III. Eleven ratios of DMPC and SM were tested from pure DMPC to pure SM. Broadness of the phase transition (T(1/2)), melting temperature of the phase transition (T(m)) and enthalpy were used to determine the relative binding affinity to the liposomes. Multilamellar vesicles composed of 40% DMPC and 60% SM showed the greatest interaction with apoLp-III, indicated by large T(1/2) values. Pure DMPC showed the weakest interaction and liposomes with lower percentage of DMPC retained domains of pure DMPC, even upon apoLp-III binding indicating demixing of liposome lipids. Addition of apoLp-III to rehydrated liposomes was compared to codissolved trials, in which lipids were rehydrated in the presence of protein, forcing the protein to interact with the lipid system. Similar trends between the codissolved and non-codissolved trials were observed, indicating a similar binding affinity except for pure DMPC. These results suggested that surface defects due to non-ideal packing that occur at the phase transition temperature of the lipid mixtures are responsible for apolipoprotein-lipid interaction in DMPC/SM liposomes.
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37
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Vasquez LJ, Abdullahi GE, Wan CPL, Weers PMM. Apolipophorin III lysine modification: Effect on structure and lipid binding. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:1901-6. [PMID: 19450543 DOI: 10.1016/j.bbamem.2009.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 05/05/2009] [Accepted: 05/11/2009] [Indexed: 10/20/2022]
Abstract
Apolipophorin III (apoLp-III) from Locusta migratoria was used as a model to investigate apolipoprotein lipid binding interactions. ApoLp-III contains eight lysine residues, of which seven are located on one side of the protein. To investigate the role of positive charges on lipid binding, lysine residues were acetylated by acetic anhydride. The degree of acetylation was analyzed by SDS-PAGE and MALDI-TOF, indicating a maximum of eight acetyl additions. Modified apoLp-III remained alpha-helical, but displayed a decreased alpha-helical content (from 78 to 54%). Acetylation resulted in a slight increase in protein stability, as indicated by a change in the midpoint of guanidine-HCl induced denaturation from 0.55 (unmodified) to 0.65 M (acetylated apoLp-III). Lipid bound apoLp-III, either acetylated or unmodified, displayed similar increases in helical content and midpoint of guanidine-HCl-induced denaturation of approximately 4 M. The ability to solubilize vesicles of dimyristoylphosphatidylcholine remained unchanged. However, the rate to solubilize dimyristoylphosphatidylglycerol vesicles was reduced two-fold. In addition, a decreased ability to stabilize diacylglycerol-enriched low density lipoproteins was observed. This indicated that lysine residues are not critical for the protein's ability to bind to zwitterionic phospholipids. Since binding interactions with ionic phospholipids and lipoproteins were affected by acetylation, lysine side-chains may play a modulating role in the interaction with more complex lipid surfaces encountered in vivo.
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Affiliation(s)
- Lesley J Vasquez
- Department of Chemistry and Biochemistry, 1250 Bellflower Blvd, California State University Long Beach, Long Beach, CA 90840, USA
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38
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Tubb MR, Silva RAGD, Pearson KJ, Tso P, Liu M, Davidson WS. Modulation of apolipoprotein A-IV lipid binding by an interaction between the N and C termini. J Biol Chem 2007; 282:28385-28394. [PMID: 17686771 DOI: 10.1074/jbc.m704070200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apolipoprotein A-IV (apoA-IV) is a 376-amino acid exchangeable apolipoprotein made in the small intestine of humans. Although it has many proposed roles in vascular disease, satiety, and chylomicron metabolism, there is no known structural basis for these functions. The ability to associate with lipids may be a key step in apoA-IV functionality. We recently identified a single amino acid, Phe(334), which seems to inhibit the lipid binding capability of apoA-IV. We also found that an intact N terminus was necessary for increased lipid binding of Phe(334) mutants. Here, we identify Trp(12) and Phe(15) as the N-terminal amino acids required for the fast lipid binding seen with the F334A mutant. Furthermore, we found that individual disruption of putative amphipathic alpha-helices 3-11 had little effect on lipid binding, suggesting that the N terminus of apoA-IV may be the operational site for initial lipid binding. We also provide three independent pieces of experimental evidence supporting a direct intramolecular interaction between sequences near amino acids 12/15 and 334. This interaction could represent a unique "switch" mechanism by which apoA-IV changes lipid avidity in vivo.
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Affiliation(s)
- Matthew R Tubb
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio 45237
| | - R A Gangani D Silva
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio 45237
| | - Kevin J Pearson
- Laboratory of Experimental Gerontology, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Patrick Tso
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio 45237
| | - Min Liu
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio 45237
| | - W Sean Davidson
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio 45237.
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39
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Tamamizu-Kato S, Kosaraju MG, Kato H, Raussens V, Ruysschaert JM, Narayanaswami V. Calcium-Triggered Membrane Interaction of the α-Synuclein Acidic Tail†. Biochemistry 2006; 45:10947-56. [PMID: 16953580 DOI: 10.1021/bi060939i] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Alpha-synuclein (alpha-syn) is a 140-residue protein that aggregates in intraneuronal inclusions called Lewy bodies in Parkinson's disease (PD). It is composed of an N-terminal domain with a propensity to bind lipids and a C-terminal domain rich in acidic residues (the acidic tail). The objective of this study was to examine the effect of Ca(2+) on the acidic tail conformation in lipid-bound alpha-syn. We exploit the extreme sensitivity of the band III fluorescence emission peak of the pyrene fluorophore to the polarity of its microenvironment to monitor subtle conformational response of the alpha-syn acidic tail to Ca(2+). Using recombinant human alpha-syn bearing a pyrene to probe either the N-terminal domain or the acidic tail, we noted that lipid binding resulted in an increase in band III emission intensity in the pyrene probe tagging the N-terminal domain but not that in the acidic tail. This suggests that the protein is anchored to the lipid surface via the N-terminal domain. However, addition of Ca(2+) caused an increase in band III emission intensity in the pyrene tagging the acidic tail, with a corresponding increased susceptibility to quenching by quenchers located in the lipid milieu, indicative of lipid interaction of this domain. Taken together with the increased beta-sheet content of membrane-associated alpha-syn in the presence of Ca(2+), we propose a model wherein initial lipid interaction occurs via the N-terminal domain, followed by a Ca(2+)-triggered membrane association of the acidic tail as a potential mechanism leading to alpha-syn aggregation. These observations have direct implications in the role of age-related oxidative stress and the attendant cellular Ca(2+) dysregulation as critical factors in alpha-syn aggregation in PD.
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Affiliation(s)
- Shiori Tamamizu-Kato
- Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, California 94609, USA
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40
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Leon LJ, Idangodage H, Wan CPL, Weers PM. Apolipophorin III: lipopolysaccharide binding requires helix bundle opening. Biochem Biophys Res Commun 2006; 348:1328-33. [PMID: 16919602 PMCID: PMC1851894 DOI: 10.1016/j.bbrc.2006.07.199] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Accepted: 07/28/2006] [Indexed: 01/28/2023]
Abstract
Apolipophorin III (apoLp-III) is a prototypical apolipoprotein used for structure-function studies. Besides its crucial role in lipid transport, apoLp-III is able to associate with fungal and bacterial membranes and stimulate cellular immune responses. We recently demonstrated binding interaction of apoLp-III of the greater wax moth, Galleria mellonella, with lipopolysaccharides (LPS). In the present study, the requirement of helix bundle opening for LPS binding interaction was investigated. Using site-directed mutagenesis, two cysteine residues were introduced in close spatial proximity (P5C/A135C). When the helix bundle was locked by disulfide bond formation, the tethered helix bundle failed to associate with LPS. In contrast, the mutant protein regained its ability to bind upon reduction with dithiothreitol. Thus, helix bundle opening is a critical event in apoLp-III binding interaction with LPS. This mechanism implies that the hydrophobic interior of the protein interacts directly with LPS, analogous to that observed for lipid interaction.
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Affiliation(s)
| | | | | | - Paul M.M. Weers
- *Corresponding author: Paul M.M. Weers, California State University Long Beach, Department of Chemistry and Biochemistry, 1250 Bellflower Blvd, Long Beach, California 90840. , Phone: +1 562 985 4948, Fax: +1 562 985 8557
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41
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Leon LJ, Pratt CC, Vasquez LJ, Weers PMM. Tyrosine fluorescence analysis of apolipophorin III–lipopolysaccharide interaction. Arch Biochem Biophys 2006; 452:38-45. [PMID: 16824478 DOI: 10.1016/j.abb.2006.05.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Revised: 05/15/2006] [Accepted: 05/17/2006] [Indexed: 11/29/2022]
Abstract
Apolipophorin III (apoLp-III) is an exchangeable apolipoprotein that binds to lipopolysaccharides (LPS). Polyacrylamide gel electrophoresis analysis demonstrated that apoLp-III from Galleria mellonella associated with various truncated LPS variants, including lipid A. Subsequent binding studies were performed employing the intrinsic tyrosine fluorescence properties of apoLp-III, which is highly quenched in the unbound state. A marked increase in tyrosine fluorescence intensity was observed upon binding to LPS or detoxified LPS, indicating a new microenvironment for Tyr-142. This also implies that the LPS carbohydrate region is involved in LPS binding. Dissociation constants (Kd) measured by apoLp-III titration were estimated at approximately 1 microM. Increasing the ionic strength did not decrease the Kd, neither did LPS phosphate removal. In addition, truncation apoLp-III mutants, lacking two complete helices, were still able to associate with LPS. This indicates that the association of apoLp-III with LPS may not be governed by charge but by hydrophobic interactions.
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Affiliation(s)
- Leonardo J Leon
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, CA 90840, USA
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42
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Weers PMM, Abdullahi WE, Cabrera JM, Hsu TC. Role of buried polar residues in helix bundle stability and lipid binding of apolipophorin III: destabilization by threonine 31. Biochemistry 2005; 44:8810-6. [PMID: 15952787 DOI: 10.1021/bi050502v] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Apolipophorin III (apoLp-III) from Locusta migratoria is a model exchangeable apolipoprotein that plays a key role in neutral lipid transport. The protein is comprised of a bundle of five amphipathic alpha-helices, with most hydrophobic residues buried in the protein interior. The low stability of apoLp-III is thought to be crucial for lipid-induced helix bundle opening, to allow protein-lipid interactions. The presence of polar residues in the hydrophobic protein interior may facilitate this role. To test this, two buried polar residues, Thr-31 and Thr-144, were changed into alanine by site-directed mutagenesis. Secondary structure analysis and GdnHCl- and temperature-induced denaturation studies indicated an increase in alpha-helical content and protein stability for T31A apoLp-III compared to wild-type apoLp-III. In contrast, T144A had a decreased alpha-helical content and protein stability, while tryptophan fluorescence indicated increased exposure of the hydrophobic interior to buffer. Two mutant proteins that had lysine residues introduced in the hydrophobic core displayed a more pronounced decrease in secondary structure and protein stability. Lipid binding studies using phospholipid vesicles showed that T31A apoLp-III was able to transform phospholipid vesicles into discoidal particles but at a 3-fold reduced rate compared to wild-type apoLp-III. In contrast, the less stable apoLp-III mutants displayed an increased ability to transform phospholipid vesicles. These results demonstrate the inverse correlation between protein stability and the ability to transform phospholipid vesicles into discoidal protein-lipid complexes and that Thr-31 is a key determinant of the relatively low protein stability, thereby promoting apoLp-III to interact with lipid surfaces.
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Affiliation(s)
- Paul M M Weers
- Department of Chemistry and Biochemistry, California State University at Long Beach, Long Beach, California 90840, USA.
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43
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Thévenin D, Lazarova T, Roberts MF, Robinson CR. Oligomerization of the fifth transmembrane domain from the adenosine A2A receptor. Protein Sci 2005; 14:2177-86. [PMID: 15987888 PMCID: PMC2279329 DOI: 10.1110/ps.051409205] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The human adenosine A2A receptor (A(2A)R) belongs to one of the largest family of membrane proteins, the G-protein coupled receptors (GPCRs), characterized by seven transmembrane (TM) helices. Little is known about the determinants of their structures, folding, assembly, activation mechanisms, and oligomeric states. Previous studies in our group showed that peptides corresponding to all seven TM domains form stable helical structures in detergent micelles and lipid vesicles. However, the peptides behave differently; TM5 is the only peptide to have a ratio [theta]222/[theta]208 obtained by circular dichroism (CD) spectroscopy>1. This finding suggested to us that TM5 might self-associate. In the present study, we investigate the unique properties of the TM5 domain. We performed detailed analyses of TM5 peptide behavior in membrane-mimetic environments using CD spectroscopy, fluorescence spectroscopy and Förster resonance energy transfer, and gel electrophoresis. We find that TM5 peptide has the ability to self-associate to form oligomeric structures in various hydrophobic milieus and that these oligomers are highly resistant to temperature and chemical denaturation. We also find that mutation of the full-length A(2A)R at position M193, which is located in the fifth TM domain, noticeably alters A(2A)R monomer: dimer ratio as observed on SDS-PAGE. Our results suggest that parallel association of TM5 dimers may play a role in the known adenosine A2A receptor dimerization. This study represents the first evidence of an individual GPCR transmembrane domain self-association.
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Affiliation(s)
- Damien Thévenin
- Department of Chemistry and Biochemistry, Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
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44
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Alexander ET, Bhat S, Thomas MJ, Weinberg RB, Cook VR, Bharadwaj MS, Sorci-Thomas M. Apolipoprotein A-I helix 6 negatively charged residues attenuate lecithin-cholesterol acyltransferase (LCAT) reactivity. Biochemistry 2005; 44:5409-19. [PMID: 15807534 DOI: 10.1021/bi047412v] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Apolipoprotein A-I (apoA-I), the major protein in high density lipoprotein (HDL) regulates cholesterol homeostasis and is protective against atherosclerosis. An examination of the amino acid sequence of apoA-I among 21 species shows a high conservation of positively and negatively charged residues within helix 6, a domain responsible for regulating the rate of cholesterol esterification in plasma. These observations prompted an investigation to determine if charged residues in helix 6 maintain a structural conformation for protein-protein interaction with lecithin-cholesterol acyltransferase (LCAT) the enzyme for which apoA-I acts as a cofactor. Three apoA-I mutants were engineered; the first, (3)/(4) no negative apoA-I, eliminated 3 of the 4 negatively charged residues in helix 6, no negative apoA-I (NN apoA-I) eliminated all four negative charges, while all negative (AN apoA-I) doubled the negative charge. Reconstituted phospholipid-containing HDL (rHDL) of two discrete sizes and compositions were prepared and tested. Results showed that LCAT activation was largely influenced by both rHDL particle size and the net negative charge on helix 6. The 80 A diameter rHDL showed a 12-fold lower LCAT catalytic efficiency when compared to 96 A diameter rHDL, apparently resulting from an increased protein-protein interaction, at the expense of lipid-protein association on the 80 A rHDL. When mutant apoproteins were compared bound to the two different sized rHDL, a strong inverse correlation (r = 0.85) was found between LCAT catalytic efficiency and apoA-I helix 6 net negative charge. These results support the concept that highly conserved negatively charged residues in apoA-I helix 6 interact directly and attenuate LCAT activation, independent of the overall particle charge.
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Affiliation(s)
- Eric T Alexander
- Department of Pathology, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, North Carolina 27157, USA
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45
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Raussens V, Drury J, Forte T, Choy N, Goormaghtigh E, Ruysschaert JM, Narayanaswami V. Orientation and mode of lipid-binding interaction of human apolipoprotein E C-terminal domain. Biochem J 2005; 387:747-54. [PMID: 15588256 PMCID: PMC1135005 DOI: 10.1042/bj20041536] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2004] [Revised: 12/02/2004] [Accepted: 12/10/2004] [Indexed: 11/17/2022]
Abstract
ApoE (apolipoprotein E) is an anti-atherogenic lipid transport protein that plays an integral role in lipoprotein metabolism and cholesterol homoeostasis. Lipid association educes critical functional features of apoE, mediating reduction in plasma and cellular cholesterol levels. The 10-kDa CT (C-terminal) domain of apoE facilitates helix-helix interactions in lipid-free state to promote apoE self-association and helix-lipid interactions during binding with lipoproteins, although the mode of lipid-binding interaction is not well understood. We investigated the mode of lipid-binding interaction and orientation of apoE CT domain on reconstituted lipoproteins. Isolated recombinant human apoE CT domain (residues 201-299) possesses a strong ability to interact with phospholipid vesicles, yielding lipoprotein particles with an apparent molecular mass of approximately 600 kDa, while retaining the overall alpha-helical content. Electron microscopy and non-denaturing PAGE analysis of DMPC (dimyristoylphosphatidylcholine)--apoE CT domain lipoprotein complexes revealed discoidal complexes with a diameter of approx. 17 nm. Cross-linking apoE CT domain on discoidal particles yielded dimeric species as the major product. Attenuated total reflectance Fourier transform IR spectroscopy of phospholipid-apoE CT domain complexes reveals that the helical axis is oriented perpendicular to fatty acyl chains of the phospholipid. Fluorescence quenching analysis of DMPC-apoE CT domain discoidal complexes by spin-labelled stearic acid indicated a relatively superficial location of the native tryptophan residues with respect to the plane of the phospholipid bilayer. Taken together, we propose that apoE CT domain interacts with phospholipid vesicles, forming a long extended helix that circumscribes the discoidal bilayer lipoprotein complex.
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Key Words
- apolipoprotein e
- cross-linking
- electron microscopy
- ir spectroscopy
- lipid-bound conformation
- lipoprotein-binding surface
- apoa-i, apolipoprotein a-i
- apoe, apolipoprotein e
- atr-ftir, attenuated total reflectance fourier transform ir
- ct, c-terminal
- dmpc, dimyristoylphosphatidylcholine
- dmpg, dimyristoylphosphatidylglycerol
- 5-dsa, 5-doxyl stearic acid
- 12-dsa, 12-doxyl stearic acid
- dss, disuccinimidyl suberate
- hdl, high-density lipoprotein
- ldl, low-density lipoprotein
- nt, n-terminal
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Affiliation(s)
- Vincent Raussens
- *Structure and Function of Biological Membranes, Université Libre de Bruxelles, CP-206/2, bd. Du Triomphe, B-1050 Brussels, Belgium
| | - Jessica Drury
- †Lipid Biology in Health and Disease Research Group, Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609, U.S.A
| | - Trudy M. Forte
- †Lipid Biology in Health and Disease Research Group, Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609, U.S.A
| | - Nicole Choy
- †Lipid Biology in Health and Disease Research Group, Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609, U.S.A
| | - Erik Goormaghtigh
- *Structure and Function of Biological Membranes, Université Libre de Bruxelles, CP-206/2, bd. Du Triomphe, B-1050 Brussels, Belgium
| | - Jean-Marie Ruysschaert
- *Structure and Function of Biological Membranes, Université Libre de Bruxelles, CP-206/2, bd. Du Triomphe, B-1050 Brussels, Belgium
| | - Vasanthy Narayanaswami
- †Lipid Biology in Health and Disease Research Group, Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609, U.S.A
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Wen Q, Mahdi AA, Briggs GS, Sharples GJ, Lloyd RG. Conservation of RecG activity from pathogens to hyperthermophiles. DNA Repair (Amst) 2005; 4:23-31. [PMID: 15533834 DOI: 10.1016/j.dnarep.2004.07.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2004] [Accepted: 07/13/2004] [Indexed: 11/24/2022]
Abstract
Maintaining the integrity of the genome is essential for the survival of all organisms. RecG helicase plays an important part in this process in Escherichia coli, promoting recombination and DNA repair, and providing ways to rescue stalled replication forks by way of a Holliday junction intermediate. We purified RecG proteins from three other species: two Gram-positive mesophiles, Bacillus subtilis and Streptococcus pneumoniae, and one extreme thermophile, Aquifex aeolicus. All three proteins bind and unwind replication fork and Holliday junction DNA molecules with efficiencies similar to the E. coli protein. Proteins from the Gram-positive species promote DNA repair in E. coli, indicating either that RecG acts alone or that any necessary protein-protein interactions are conserved. The S. pneumoniae RecG reduces plasmid copy number when expressed in E. coli, indicating that like the E. coli protein it unwinds plasmid R loop structures used to prime replication. This effect is not seen with B. subtilis RecG; the protein either lacks R loop unwinding activity or is compromised by having insufficient ATP. The A. aeolicus protein unwinds DNA well at 60 degrees C but is less efficient at 37 degrees C, explaining its inability to function in E. coli at this temperature. The N-terminal extension present in this protein was investigated and found to be dispensable for activity and thermo-stability. The results presented suggest that the role of RecG in DNA replication and repair is likely to be conserved throughout all bacteria, which underlines the importance of this protein in genome duplication and cell survival.
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Affiliation(s)
- Qin Wen
- Queens Medical Centre, Institute of Genetics, University of Nottingham, Nottingham NG7 2UH, UK
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Drury J, Narayanaswami V. Examination of lipid-bound conformation of apolipoprotein E4 by pyrene excimer fluorescence. J Biol Chem 2005; 280:14605-10. [PMID: 15708851 DOI: 10.1074/jbc.m414019200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apolipoprotein E (apoE) is a 34-kDa resident of lipoproteins that plays a key role in cholesterol homeostasis in plasma and in brain. It is composed of an N-terminal (NT) domain (residues 1-191) and a C-terminal (CT) domain (residues 201-299). Of the three major isoforms (apoE2, -E3, and -E4), apoE4 is considered a risk factor for both cardiovascular and Alzheimer disease. Compared with apoE3, domain interaction between NT and CT domains is believed to direct the lipoprotein distribution preference of apoE4 for very low density lipoprotein-sized particles. We examined the relative disposition of apoE4 NT and CT domains in lipid-free and lipid-bound forms by monitoring pyrene excimer fluorescence emission as a direct indicator of spatial proximity. Site-specific labeling of apoE4 by N-(1-pyrene)maleimide was accomplished after substitution of Cys residues for Arg-61 in NT domain and Glu-255 in CT domain. Pyrene labeling did not alter the lipoprotein distribution pattern of apoE4 in plasma. Pyrene excimer fluorescence was noted in lipid-free pyrene-R61C/E255C/apoE4 in mixtures containing excess wild-type apoE4, which was attributed to intramolecular spatial proximity between these specified sites. Upon disruption of tertiary interaction, a large decrease in excimer fluorescence emission was noted in pyrene-R61C/E255C/apoE4. In dimyristoylphosphatidylcholine/pyrene-R61C/E255C/apoE4 discoidal complexes, pyrene excimer fluorescence emission was retained. Taken together with fluorescence quenching and cross-linking analysis, a looped-back model of apoE4 is proposed in lipid-bound state, including spherical lipoprotein particles, wherein residues Arg-61 and Glu-255 are proximal to one another.
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Affiliation(s)
- Jessica Drury
- Lipid Biology in Health and Disease Research Group, Children's Hospital Oakland Research Institute, Oakland, California 94609, USA
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48
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Dowhan W, Mileykovskaya E, Bogdanov M. Diversity and versatility of lipid-protein interactions revealed by molecular genetic approaches. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1666:19-39. [PMID: 15519306 PMCID: PMC4109649 DOI: 10.1016/j.bbamem.2004.04.010] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Accepted: 04/21/2004] [Indexed: 10/26/2022]
Abstract
The diversity in structures and physical properties of lipids provides a wide variety of possible interactions with proteins that affect their assembly, organization, and function either at the surface of or within membranes. Because lipids have no catalytic activity, it has been challenging to define many of their precise functions in vivo in molecular terms. Those processes responsive to lipids are attuned to the native lipid environment for optimal function, but evidence that lipids with similar properties or even detergents can sometimes partially replace the natural lipid environment has led to uncertainty as to the requirement for specific lipids. The development of strains of microorganisms in which membrane lipid composition can be genetically manipulated in viable cells has provided a set of reagents to probe lipid functions. These mutants have uncovered previously unrecognized roles for lipids and provided in vivo verification for putative functions described in vitro. In this review, we summarize how these reagent strains have provided new insight into the function of lipids. The role of specific lipids in membrane protein folding and topological organization is reviewed. The evidence is summarized for the involvement of anionic lipid-enriched domains in the organization of amphitropic proteins on the membrane surface into molecular machines involved in DNA replication and cell division.
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Affiliation(s)
- William Dowhan
- Department of Biochemistry and Molecular Biology, University of Texas-Houston, Medical School, Suite 6.200, 6431 Fannin St., Houston, TX, 77030, USA.
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Pratt CC, Weers PMM. Lipopolysaccharide binding of an exchangeable apolipoprotein, apolipophorin III, from Galleria mellonella. Biol Chem 2004; 385:1113-9. [PMID: 15576334 DOI: 10.1515/bc.2004.145] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
AbstractA new role of apolipophorin III (apoLp-III) as an immune activator has emerged recently. To gain insight into this novel function, the interaction of apoLp-III with lipopoly-saccharide (LPS) was investigated. ApoLp-III fromGalleria mellonellawas incubated with LPS fromEscherichia coliO55:B5, and analyzed by non-denaturing polyacrylamide gel electrophoresis (PAGE). Protein staining showed that apoLp-III mobility was significantly reduced. In addition, silver and LPS fluorescent staining demonstrated that LPS mobility was increased upon incubation with apoLp-III. This result suggests association of apoLp-III with LPS. Sodium dodecyl sulfate (SDS) PAGE analysis showed decreased apoLp-III mobility upon LPS addition, indicative of LPS apoLp-III interaction in the presence of SDS. The unique tyrosine residue that resides in apoLp-III was used to provide additional evidence for LPS binding interaction. In the absence of LPS, apoLp-III tyrosine fluorescence was relatively low. However, LPS addition resulted in a progressive increase in the fluorescence intensity, indicating tertiary rearrangement in the environment of tyrosine 142 upon LPS interaction. Other well-characterized apoLp-IIIs were also examined for LPS binding.Manduca sexta,Bombyx moriandLocusta migratoriaapoLp-III were all able to interact with LPS. The ability of apoLp-III to form complexes with LPS supports the proposed role of apoLp-III in innate immunity.
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Affiliation(s)
- Cindy C Pratt
- Department of Chemistry and Biochemistry, California State University at Long Beach, Long Beach, CA 90840, USA
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50
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Van der Horst DJ. Insect adipokinetic hormones: release and integration of flight energy metabolism. Comp Biochem Physiol B Biochem Mol Biol 2004; 136:217-26. [PMID: 14529748 DOI: 10.1016/s1096-4959(03)00151-9] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Insect flight involves mobilization, transport and utilization of endogenous energy reserves at extremely high rates. Peptide adipokinetic hormones (AKHs), synthesized and stored in neuroendocrine cells, integrate flight energy metabolism. The complex multifactorial control mechanism for AKH release in the locust includes both stimulatory and inhibitory factors. The AKHs are synthesized continuously, resulting in an accumulation of AKH-containing secretory granules. Additionally, secretory material is stored in large intracisternal granules. Although only a limited part of these large reserves appears to be readily releasable, this strategy allows the adipokinetic cells to comply with large variations in secretory demands; changes in secretory activity do not affect the rate of hormone biosynthesis. AKH-induced lipid release from fat body target cells has revealed a novel concept for lipid transport during exercise. Similar to sustained locomotion of mammals, insect flight activity is powered by oxidation of free fatty acids derived from endogenous reserves of triacylglycerol. However, the transport form of the lipid in the circulatory system is diacylglycerol (DAG) that is delivered to the flight muscles associated with lipoproteins. While DAG is loaded onto the multifunctional insect lipoprotein, high-density lipophorin (HDLp) and multiple copies of the exchangeable apolipoprotein III (apoLp-III) associate reversibly with the expanding particle. The resulting low-density lipophorin (LDLp) specifically shuttles DAG to the working muscles. Following DAG hydrolysis by a lipophorin lipase, apoLp-III dissociates from the particle, regenerating HDLp that is re-utilized for lipid uptake at the fat body cells, thus functioning as an efficient lipid shuttle mechanism. Many structural elements of the lipoprotein system of insects appear to be similar to their counterparts in mammals; however, the functioning of the insect lipoprotein in energy transport during flight activity is intriguingly different.
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Affiliation(s)
- Dick J Van der Horst
- Department of Biochemical Physiology and Institute of Biomembranes, Utrecht University, Padualaan 8, Utrecht 3584 CH, The Netherlands.
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