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] [What about the content of this article? (0)] [Affiliation(s)] [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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Petronio Petronio G, Pietrangelo L, Cutuli MA, Magnifico I, Venditti N, Guarnieri A, Abate GA, Yewhalaw D, Davinelli S, Di Marco R. Emerging Evidence on Tenebrio molitor Immunity: A Focus on Gene Expression Involved in Microbial Infection for Host-Pathogen Interaction Studies. Microorganisms 2022; 10:1983. [PMID: 36296259 PMCID: PMC9611967 DOI: 10.3390/microorganisms10101983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 09/30/2022] [Accepted: 10/02/2022] [Indexed: 08/13/2023] Open
Abstract
In recent years, the scientific community's interest in T. molitor as an insect model to investigate immunity and host-pathogen interactions has considerably increased. The reasons for this growing interest could be explained by the peculiar features of this beetle, which offers various advantages compared to other invertebrates models commonly used in laboratory studies. Thus, this review aimed at providing a broad view of the T. molitor immune system in light of the new scientific evidence on the developmental/tissue-specific gene expression studies related to microbial infection. In addition to the well-known cellular component and humoral response process, several studies investigating the factors associated with T. molitor immune response or deepening of those already known have been reported. However, various aspects remain still less understood, namely the possible crosstalk between the immune deficiency protein and Toll pathways and the role exerted by T. molitor apolipoprotein III in the expression of the antimicrobial peptides. Therefore, further research is required for T. molitor to be recommended as an alternative insect model for pathogen-host interaction and immunity studies.
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Affiliation(s)
- Giulio Petronio Petronio
- Department of Medicine and Health Science “V. Tiberio”, Università degli Studi del Molise, 8600 Campobasso, Italy
| | - Laura Pietrangelo
- Department of Medicine and Health Science “V. Tiberio”, Università degli Studi del Molise, 8600 Campobasso, Italy
| | - Marco Alfio Cutuli
- Department of Medicine and Health Science “V. Tiberio”, Università degli Studi del Molise, 8600 Campobasso, Italy
| | - Irene Magnifico
- Department of Medicine and Health Science “V. Tiberio”, Università degli Studi del Molise, 8600 Campobasso, Italy
| | - Noemi Venditti
- Department of Medicine and Health Science “V. Tiberio”, Università degli Studi del Molise, 8600 Campobasso, Italy
| | - Antonio Guarnieri
- Department of Medicine and Health Science “V. Tiberio”, Università degli Studi del Molise, 8600 Campobasso, Italy
| | - Getnet Atinafu Abate
- Department of Biology, College of Natural Sciences, Debre Markos University, Debre Markos P.O. Box 269, Ethiopia
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma P.O. Box 307, Ethiopia
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma P.O. Box 378, Ethiopia
| | - Sergio Davinelli
- Department of Medicine and Health Science “V. Tiberio”, Università degli Studi del Molise, 8600 Campobasso, Italy
| | - Roberto Di Marco
- Department of Medicine and Health Science “V. Tiberio”, Università degli Studi del Molise, 8600 Campobasso, Italy
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3
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Farha S, Comhair S, Hou Y, Park MM, Sharp J, Peterson L, Willard B, Zhang R, DiFilippo FP, Neumann D, Tang WHW, Cheng F, Erzurum S. Metabolic endophenotype associated with right ventricular glucose uptake in pulmonary hypertension. Pulm Circ 2021; 11:20458940211054325. [PMID: 34888034 PMCID: PMC8649443 DOI: 10.1177/20458940211054325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 10/01/2021] [Indexed: 11/25/2022] Open
Abstract
Alterations in metabolism and bioenergetics are hypothesized in the mechanisms
leading to pulmonary vascular remodeling and heart failure in pulmonary
hypertension (PH). To test this, we performed metabolomic analyses on 30 PH
individuals and 12 controls. Furthermore, using 2-[18F]fluoro-2-deoxy-D-glucose
positron emission tomography, we dichotomized PH patients into metabolic
phenotypes of high and low right ventricle (RV) glucose uptake and followed them
longitudinally. In support of metabolic alterations in PH and its progression,
the high RV glucose group had higher RV systolic pressure (p < 0.001), worse
RV function as measured by RV fractional area change and peak global
longitudinal strain (both p < 0.05) and may be associated with poorer
outcomes (33% death or transplantation in the high glucose RV uptake group
compared to 7% in the low RV glucose uptake group at five years follow-up,
log-ranked p = 0.07). Pathway enrichment analysis identified key metabolic
pathways including fructose catabolism, arginine-nitric oxide metabolism,
tricarboxylic acid cycle, and ketones metabolism. Integrative human
protein-protein interactome network analysis of metabolomic and transcriptomic
data identified key pathobiological pathways: arginine biosynthesis,
tricarboxylic acid cycle, purine metabolism, hypoxia-inducible factor 1, and
apelin signaling. These findings identify a PH metabolomic endophenotype, and
for the first time link this to disease severity and outcomes.
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Affiliation(s)
- Samar Farha
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.,Respiratory Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Suzy Comhair
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Yuan Hou
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Margaret M Park
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.,Heart Vascular and Thoracic Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Jacqueline Sharp
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.,Heart Vascular and Thoracic Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Laura Peterson
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Belinda Willard
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Renliang Zhang
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | | | - W H Wilson Tang
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.,Heart Vascular and Thoracic Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Feixiong Cheng
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Serpil Erzurum
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.,Respiratory Institute, Cleveland Clinic, Cleveland, OH, USA
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4
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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5
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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6
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Maravilla E, Le DP, Tran JJ, Chiu MH, Prenner EJ, Weers PM. 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] [What about the content of this article? (0)] [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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7
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Yang F, Zhu B, Liu J, Liu Y, Jiang C, Sheng Q, Qiu J, Nie Z. The effect of acetylation on the protein stability of BmApoLp-III in the silkworm, Bombyx mori. Insect Mol Biol 2020; 29:104-111. [PMID: 31390480 DOI: 10.1111/imb.12613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 05/26/2019] [Accepted: 07/30/2019] [Indexed: 06/10/2023]
Abstract
Acetylation is an important, reversible posttranslational modification to a protein. In a previous study, we found that there were a large number of acetylated sites in various nutrient storage proteins of the silkworm haemolymph. In this study, we confirmed that acetylation can affect the stability of nutrient storage protein Bombyx mori apolipophorin-III (BmApoLp-III). First, the expression of BmApoLp-III could be upregulated when BmN cells were treated with the deacetylase inhibitor panobinostat (LBH589); similarly, the expression was downregulated when the cells were treated with the acetylase inhibitor C646. Furthermore, the increase in acetylation by LBH589 could inhibit the degradation and improve the accumulation of BmApoLp-III in BmN cells treated with cycloheximide and MG132 respectively. Moreover, we found that an increase in acetylation could decrease the ubiquitination of BmApoLp-III and vice versa; therefore, we predicted that acetylation could improve the stability of BmApoLp-III by competing for ubiquitination and inhibiting the protein degradation pathway mediated by ubiquitin. Additionally, BmApoLp-III had an antiapoptosis function that increased after LBH589 treatment, which might have been due to the improved protein stability after acetylation. These results have laid the foundation for further study on the mechanism of acetylation in regulating the storage and utilization of silkworm nutrition.
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Affiliation(s)
- F Yang
- College of Life Sciences and medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - B Zhu
- College of Life Sciences and medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - J Liu
- School of Forestry and Biotechnology, Zhejiang A&F University, Linan, China
| | - Y Liu
- Zhejiang Economic & Trade Polytechnic, Hangzhou, China
| | - C Jiang
- College of Life Sciences and medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Q Sheng
- College of Life Sciences and medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - J Qiu
- College of Life Sciences and medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Z Nie
- College of Life Sciences and medicine, Zhejiang Sci-Tech University, Hangzhou, China
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8
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Wijeratne TU, Weers PMM. 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] [What about the content of this article? (0)] [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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9
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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. J Insect Physiol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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10
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He W, Felderman M, Evans AC, Geng J, Homan D, Bourguet F, Fischer NO, Li Y, Lam KS, Noy A, Xing L, Cheng RH, Rasley A, Blanchette CD, Kamrud K, Wang N, Gouvis H, Peterson TC, Hubby B, Coleman MA. Cell-free production of a functional oligomeric form of a Chlamydia major outer-membrane protein (MOMP) for vaccine development. J Biol Chem 2017; 292:15121-15132. [PMID: 28739800 DOI: 10.1074/jbc.m117.784561] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 07/13/2017] [Indexed: 11/06/2022] Open
Abstract
Chlamydia is a prevalent sexually transmitted disease that infects more than 100 million people worldwide. Although most individuals infected with Chlamydia trachomatis are initially asymptomatic, symptoms can arise if left undiagnosed. Long-term infection can result in debilitating conditions such as pelvic inflammatory disease, infertility, and blindness. Chlamydia infection, therefore, constitutes a significant public health threat, underscoring the need for a Chlamydia-specific vaccine. Chlamydia strains express a major outer-membrane protein (MOMP) that has been shown to be an effective vaccine antigen. However, approaches to produce a functional recombinant MOMP protein for vaccine development are limited by poor solubility, low yield, and protein misfolding. Here, we used an Escherichia coli-based cell-free system to express a MOMP protein from the mouse-specific species Chlamydia muridarum (MoPn-MOMP or mMOMP). The codon-optimized mMOMP gene was co-translated with Δ49apolipoprotein A1 (Δ49ApoA1), a truncated version of mouse ApoA1 in which the N-terminal 49 amino acids were removed. This co-translation process produced mMOMP supported within a telodendrimer nanolipoprotein particle (mMOMP-tNLP). The cell-free expressed mMOMP-tNLPs contain mMOMP multimers similar to the native MOMP protein. This cell-free process produced on average 1.5 mg of purified, water-soluble mMOMP-tNLP complex in a 1-ml cell-free reaction. The mMOMP-tNLP particle also accommodated the co-localization of CpG oligodeoxynucleotide 1826, a single-stranded synthetic DNA adjuvant, eliciting an enhanced humoral immune response in vaccinated mice. Using our mMOMP-tNLP formulation, we demonstrate a unique approach to solubilizing and administering membrane-bound proteins for future vaccine development. This method can be applied to other previously difficult-to-obtain antigens while maintaining full functionality and immunogenicity.
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Affiliation(s)
- Wei He
- From the Lawrence Livermore National Laboratory, Livermore, California 94550
| | | | - Angela C Evans
- From the Lawrence Livermore National Laboratory, Livermore, California 94550
| | - Jia Geng
- From the Lawrence Livermore National Laboratory, Livermore, California 94550.,School of Natural Sciences, University of California, Merced, California 95343
| | - David Homan
- From the Lawrence Livermore National Laboratory, Livermore, California 94550
| | - Feliza Bourguet
- From the Lawrence Livermore National Laboratory, Livermore, California 94550
| | - Nicholas O Fischer
- From the Lawrence Livermore National Laboratory, Livermore, California 94550
| | - Yuanpei Li
- the Department of Biochemistry and Molecular Medicine and
| | - Kit S Lam
- the Department of Biochemistry and Molecular Medicine and
| | - Aleksandr Noy
- From the Lawrence Livermore National Laboratory, Livermore, California 94550.,School of Natural Sciences, University of California, Merced, California 95343
| | - Li Xing
- the Department of Molecular and Cellular Biology, University of California, Davis, California 95618
| | - R Holland Cheng
- the Department of Molecular and Cellular Biology, University of California, Davis, California 95618
| | - Amy Rasley
- From the Lawrence Livermore National Laboratory, Livermore, California 94550
| | - Craig D Blanchette
- From the Lawrence Livermore National Laboratory, Livermore, California 94550
| | - Kurt Kamrud
- Synthetic Genomics Vaccine Inc., La Jolla, California 92037
| | - Nathaniel Wang
- Synthetic Genomics Vaccine Inc., La Jolla, California 92037
| | - Heather Gouvis
- Synthetic Genomics Vaccine Inc., La Jolla, California 92037
| | | | - Bolyn Hubby
- Synthetic Genomics Vaccine Inc., La Jolla, California 92037
| | - Matthew A Coleman
- From the Lawrence Livermore National Laboratory, Livermore, California 94550, .,Radiation Oncology, School of Medicine, University of California Davis, Sacramento, California 95817, and
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11
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Abstract
Membrane proteins play a most important part in metabolism, signaling, cell motility, transport, development, and many other biochemical and biophysical processes which constitute fundamentals of life on the molecular level. Detailed understanding of these processes is necessary for the progress of life sciences and biomedical applications. Nanodiscs provide a new and powerful tool for a broad spectrum of biochemical and biophysical studies of membrane proteins and are commonly acknowledged as an optimal membrane mimetic system that provides control over size, composition, and specific functional modifications on the nanometer scale. In this review we attempted to combine a comprehensive list of various applications of nanodisc technology with systematic analysis of the most attractive features of this system and advantages provided by nanodiscs for structural and mechanistic studies of membrane proteins.
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Affiliation(s)
- Ilia G Denisov
- Department of Biochemistry and Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States
| | - Stephen G Sligar
- Department of Biochemistry and Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States
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12
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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13
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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14
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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). Arch Insect Biochem Physiol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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15
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Zdybicka-barabas A, Palusińska-szysz M, Gruszecki WI, Mak P, Cytryńska M. Galleria mellonella apolipophorin III – an apolipoprotein with anti-Legionella pneumophila activity. Biochimica et Biophysica Acta (BBA) - 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] [What about the content of this article? (0)] [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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16
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Cuellar LÁ, Prieto ED, Cabaleiro LV, Garda HA. Apolipoprotein A-I configuration and cell cholesterol efflux activity of discoidal lipoproteins depend on the reconstitution process. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:180-9. [DOI: 10.1016/j.bbalip.2013.10.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 10/02/2013] [Accepted: 10/24/2013] [Indexed: 12/31/2022]
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17
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Lin P, Chen X, Moktan H, Arrese EL, Duan L, Wang L, Soulages JL, Zhou DH. Membrane attachment and structure models of lipid storage droplet protein 1. Biochim Biophys Acta 2013; 1838:874-81. [PMID: 24333382 DOI: 10.1016/j.bbamem.2013.12.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 11/29/2013] [Accepted: 12/05/2013] [Indexed: 02/08/2023]
Abstract
Neutral lipid triglycerides, a main reserve for fat and energy, are stored in organelles called lipid droplets. The storage and release of triglycerides are actively regulated by several proteins specific to the droplet surface, one of which in insects is PLIN1. PLIN1 plays a key role in the activation of triglyceride hydrolysis upon phosphorylation. However, the structure of PLIN1 and its relation to functions remain elusive due to its insolubility and crystallization difficulty. Here we report the first solid-state NMR study on the Drosophila melanogaster PLIN1 in combination with molecular dynamics simulation to show the structural basis for its lipid droplet attachment. NMR spin diffusion experiments were consistent with the predicted membrane attachment motif of PLIN1. The data indicated that PLIN1 has close contact with the terminal methyl groups of the phospholipid acyl chains. Structure models for the membrane attachment motif were generated based on hydrophobicity analysis and NMR membrane insertion depth information. Simulated NMR spectra from a trans-model agreed with experimental spectra. In this model, lipids from the bottom leaflet were very close to the surface in the region enclosed by membrane attachment motif. This may imply that in real lipid droplet, triglyceride molecules might be brought close to the surface by the same mechanism, ready to leave the droplet in the event of lipolysis. Juxtaposition of triglyceride lipase structure to the trans-model suggested a possible interaction of a conserved segment with the lipase by electrostatic interactions, opening the lipase lid to expose the catalytic center.
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Affiliation(s)
- Penghui Lin
- Department of Physics, 230 L Henry Bellmon Research Center, Oklahoma State University, Stillwater, OK 74078, USA
| | - Xiao Chen
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Hem Moktan
- Department of Physics, 230 L Henry Bellmon Research Center, Oklahoma State University, Stillwater, OK 74078, USA
| | - Estela L Arrese
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Lian Duan
- Department of Physics, 230 L Henry Bellmon Research Center, Oklahoma State University, Stillwater, OK 74078, USA
| | - Liying Wang
- Department of Physics, 230 L Henry Bellmon Research Center, Oklahoma State University, Stillwater, OK 74078, USA; State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Wuhan Center for Magnetic Resonance, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jose L Soulages
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Donghua H Zhou
- Department of Physics, 230 L Henry Bellmon Research Center, Oklahoma State University, Stillwater, OK 74078, USA.
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18
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Prieto ED, Garda HA. Membrane insertion topology of the central apolipoprotein A-I region. Fluorescence studies using single tryptophan mutants. Biochemistry 2010; 50:466-79. [PMID: 21141907 DOI: 10.1021/bi1009634] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Apolipoprotein A-I (apoAI) contains several amphipathic α-helices. To carry out its function, it exchanges between lipid-free and different lipidated states as bound to membranes or to lipoprotein complexes of different morphology, size, and composition. When bound to membranes or to spherical lipoprotein surfaces, it is thought that most α-helices arrange with their long axis parallel to the membrane surface. However, we previously found that a central region spanning residues 87-112 is exclusively labeled by photoactivable reagents deeply located into the membrane (Córsico et al. (2001) J. Biol. Chem. 276, 16978-16985). A pair of amphipathic α-helical repeats with a particular charge distribution is predicted in this region. In order to study their insertion topology, three single tryptophan mutants, each one containing the tryptophan residue at a selected position in the hydrophobic face of the central Y-helices (W@93, W@104, and W@108), were used. From the accessibility to quenchers located at different membrane depths, distances from the bilayer center of 13.4, 10.5, and 15.7 Å were estimated for positions 93, 104, and 108, respectively. Reported data also indicate that distances between homologous positions (in particular for W@93 and W@104) are very short in dimers in aqueous solution, but they are larger in membrane-bound dimers. Data indicate that an intermolecular central Y-helix bundle would penetrate the membrane perpendicularly to the membrane surface. Intermolecular helix-helix interactions would occur through the hydrophilic helix faces in the membrane-bound bundle but through the hydrophobic faces in the case of dimers in solution.
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Affiliation(s)
- Eduardo D Prieto
- Instituto de Investigaciones Bioquímicas de La Plata, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de La Plata, Facultad de Ciencias Médicas, Calles 60 y 120, La Plata, Argentina
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19
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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. Biochim Biophys Acta 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] [What about the content of this article? (0)] [Affiliation(s)] [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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20
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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21
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Chiu MH, Wan CP, Weers PM, Prenner EJ. Apolipophorin III interaction with model membranes composed of phosphatidylcholine and sphingomyelin using differential scanning calorimetry. Biochim Biophys Acta 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] [What about the content of this article? (0)] [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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22
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Blanchette CD, Segelke BW, Fischer N, Corzett MH, Kuhn EA, Cappuccio JA, Benner WH, Coleman MA, Chromy BA, Bench G, Hoeprich PD, Sulchek TA. Characterization and purification of polydisperse reconstituted lipoproteins and nanolipoprotein particles. Int J Mol Sci 2009; 10:2958-71. [PMID: 19742178 DOI: 10.3390/ijms10072958] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Accepted: 06/22/2009] [Indexed: 01/29/2023] Open
Abstract
Heterogeneity is a fact that plagues the characterization and application of many self-assembled biological constructs. The importance of obtaining particle homogeneity in biological assemblies is a critical goal, as bulk analysis tools often require identical species for reliable interpretation of the results—indeed, important tools of analysis such as x-ray diffraction typically require over 90% purity for effectiveness. This issue bears particular importance in the case of lipoproteins. Lipid-binding proteins known as apolipoproteins can self assemble with liposomes to form reconstituted high density lipoproteins (rHDLs) or nanolipoprotein particles (NLPs) when used for biotechnology applications such as the solubilization of membrane proteins. Typically, the apolipoprotein and phospholipids reactants are self assembled and even with careful assembly protocols the product often contains heterogeneous particles. In fact, size polydispersity in rHDLs and NLPs published in the literature are frequently observed, which may confound the accurate use of analytical methods. In this article, we demonstrate a procedure for producing a pure, monodisperse NLP subpopulation from a polydisperse self-assembly using size exclusion chromatography (SEC) coupled with high resolution particle imaging by atomic force microscopy (AFM). In addition, NLPs have been shown to self assemble both in the presence and absence of detergents such as cholate, yet the effects of cholate on NLP polydispersity and separation has not been systematically examined. Therefore, we examined the separation properties of NLPs assembled in both the absence and presence of cholate using SEC and native gel electrophoresis. From this analysis, NLPs prepared with and without cholate showed particles with well defined diameters spanning a similar size range. However, cholate was shown to have a dramatic affect on NLP separation by SEC and native gel electrophoresis. Furthermore, under conditions where different sized NLPs were not sufficiently separated or purified by SEC, AFM was used to deconvolute the elution pattern of different sized NLPs. From this analysis we were able to purify an NLP subpopulation to 90% size homogeneity by taking extremely fine elutions from the SEC. With this purity, we generate high quality NLP crystals that were over 100 μm in size with little precipitate, which could not be obtained utilizing the traditional size exclusion techniques. This purification procedure and the methods for validation are broadly applicable to other lipoprotein particles.
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Vasquez LJ, Abdullahi GE, Wan CPL, Weers PMM. Apolipophorin III lysine modification: Effect on structure and lipid binding. Biochim Biophys Acta 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Blanchette CD, Law R, Benner WH, Pesavento JB, Cappuccio JA, Walsworth V, Kuhn EA, Corzett M, Chromy BA, Segelke BW, Coleman MA, Bench G, Hoeprich PD, Sulchek TA. Quantifying size distributions of nanolipoprotein particles with single-particle analysis and molecular dynamic simulations. J Lipid Res 2008; 49:1420-30. [PMID: 18403317 DOI: 10.1194/jlr.m700586-jlr200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Self-assembly of purified apolipoproteins and phospholipids results in the formation of nanometer-sized lipoprotein complexes, referred to as nanolipoprotein particles (NLPs). These bilayer constructs are fully soluble in aqueous environments and hold great promise as a model system to aid in solubilizing membrane proteins. Size variability in the self-assembly process has been recognized for some time, yet limited studies have been conducted to examine this phenomenon. Understanding the source of this heterogeneity may lead to methods to mitigate heterogeneity or to control NLP size, which may be important for tailoring NLPs for specific membrane proteins. Here, we have used atomic force microscopy, ion mobility spectrometry, and transmission electron microscopy to quantify NLP size distributions on the single-particle scale, specifically focusing on assemblies with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and a recombinant apolipoprotein E variant containing the N-terminal 22 kDa fragment (E422k). Four discrete sizes of E422k/DMPC NLPs were identified by all three techniques, with diameters centered at approximately 14.5, 19, 23.5, and 28 nm. Computer simulations suggest that these sizes are related to the structure and number of E422k lipoproteins surrounding the NLPs and particles with an odd number of lipoproteins are consistent with the double-belt model, in which at least one lipoprotein adopts a hairpin structure.
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Affiliation(s)
- Craig D Blanchette
- Chemistry, Materials, and Life Sciences, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
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Chromy BA, Arroyo E, Blanchette CD, Bench G, Benner H, Cappuccio JA, Coleman MA, Henderson PT, Hinz AK, Kuhn EA, Pesavento JB, Segelke BW, Sulchek TA, Tarasow T, Walsworth VL, Hoeprich PD. Different Apolipoproteins Impact Nanolipoprotein Particle Formation. J Am Chem Soc 2007; 129:14348-54. [DOI: 10.1021/ja074753y] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Benjwal S, Jayaraman S, Gursky O. Role of secondary structure in protein-phospholipid surface interactions: reconstitution and denaturation of apolipoprotein C-I:DMPC complexes. Biochemistry 2007; 46:4184-94. [PMID: 17341095 PMCID: PMC2584444 DOI: 10.1021/bi062175c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Binding of protein to a phospholipid surface is commonly mediated by amphipathic alpha-helices. To understand the role of alpha-helical structure in protein-lipid interactions, we used discoidal lipoproteins reconstituted from dimyristoylphosphatidylcholine (DMPC) and human apolipoprotein C-I (apoC-I, 6 kDa) or its mutants containing single Pro substitutions along the sequence and differing in their alpha-helical content in solution (0-48%) and on DMPC (40-75%). Thermal denaturation revealed that lipoprotein stability correlates weakly with the protein helix content: proteins with higher alpha-helical content on DMPC may form more stable complexes. Lipoprotein reconstitution upon cooling from the heat-denatured state and DMPC clearance studies revealed that protein secondary structure in solution and on DMPC correlates strongly with the maximal temperature of lipoprotein reconstitution: more helical proteins can reconstitute lipoproteins at higher temperatures. Interestingly, at Tc = 24 degrees C of the DMPC gel-to-liquid crystal transition, the clearance rate is independent of the protein helical content. Consequently, if the packing defects at the phospholipid surface are readily available (e.g., at the lipid phase boundary), insertion of protein into these defects is independent of the secondary structure in solution. However, if hydrophobic defects are limited, protein binding and insertion are aided by other surface-bound proteins and depend on their helical propensity: the larger the propensity, the faster the binding and the broader its temperature range. This positive cooperativity in binding of alpha-helices to phospholipid surface, which may result from direct and/or lipid-mediated protein-protein interactions, may be important for lipoprotein metabolism and for protein-membrane binding.
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Affiliation(s)
- Sangeeta Benjwal
- Department of Physiology and Biophysics, Boston University School of Medicine, 715 Albany Street, Boston, Massachusetts 02118, USA
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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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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Abstract
Using a recently described self-assembly process (Bayburt, T. H.; Grinkova, Y. V.; Sligar, S. G. Nano Letters 2002, 2, 853-856), we prepared soluble monodisperse discoidal lipid/protein particles with controlled size and composition, termed Nanodiscs, in which the fragment of dipalmitoylphosphatidylcholine (DPPC) bilayer is surrounded by a helical protein belt. We have customized the size of these particles by changing the length of the amphipathic helical part of this belt, termed membrane scaffold protein (MSP). Herein we describe the design of extended and truncated MSPs, the optimization of self-assembly for each of these proteins, and the structure and composition of the resulting Nanodiscs. We show that the length of the protein helix surrounding the lipid part of a Nanodisc determines the particle diameter, as measured by HPLC and small-angle X-ray scattering (SAXS). Using different scaffold proteins, we obtained Nanodiscs with the average size from 9.5 to 12.8 nm with a very narrow size distribution (+/-3%). Functionalization of the N-terminus of the scaffold protein does not perturb their ability to form homogeneous discoidal structures. Detailed analysis of the solution scattering confirms the presence of a lipid bilayer of 5.5 nm thickness in Nanodiscs of different sizes. The results of this study provide an important structural characterization of self-assembled phospholipid bilayers and establish a framework for the design of soluble amphiphilic nanoparticles of controlled size.
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Affiliation(s)
- I G Denisov
- Departments of Biochemistry and Chemistry and the Beckman Institute, University of Illinois, Urbana, Illinois 61801, USA
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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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Abstract
Apolipophorin III (apoLp-III) is a low molecular weight exchangeable apolipoprotein that plays an important role in the enhanced neutral lipid transport during insect flight. The protein exists in lipid-free and lipid-bound states. The lipid-bound state is the active form of the protein and occurs when apoLp-III associates with lipid-enriched lipophorins. ApoLp-III is well characterized in two evolutionally divergent species: Locusta migratoria and Manduca sexta. The two apolipoproteins interact in a similar manner with model phospholipid vesicles, and transform them into discoidal particles. Their low intrinsic stability in the lipid-free state likely facilitates interaction with lipid surfaces. Low solution pH also favors lipid binding interaction through increased exposure of hydrophobic surfaces on apoLp-III. While secondary structure is maintained under acidic conditions, apoLp-III tertiary structure is altered, adopting molten globule-like characteristics. In studies of apoLp-III interaction with natural lipoproteins, we found that apoLp-III is readily displaced from the surface of L. migratoria low-density lipophorin by recombinant apoLp-III proteins from either L. migratoria or M. sexta. Thus, despite important differences between these two apoLp-IIIs (amino acid sequence, presence of carbohydrate), their functional similarity is striking. This similarity is also illustrated by the recently published NMR solution structure of M. sexta apoLp-III wherein its molecular architecture closely parallels that of L. migratoria apoLp-III.
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Affiliation(s)
- Paul M M Weers
- Department of Chemistry and Biochemistry, California State University Long Beach, 1250 Bellflower Boulevard, Long Beach, CA 90840, USA.
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Li HH, Lyles DS, Pan W, Alexander E, Thomas MJ, Sorci-Thomas MG. ApoA-I structure on discs and spheres. Variable helix registry and conformational states. J Biol Chem 2002; 277:39093-101. [PMID: 12167653 DOI: 10.1074/jbc.m206770200] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apolipoprotein A-I (apoA-I) readily forms discoidal high density lipoprotein (HDL) particles with phospholipids serving as an ideal transporter of plasma cholesterol. In the lipid-bound conformation, apoA-I activates the enzyme lecithin:cholesterol acyltransferase stimulating the formation of cholesterol esters from free cholesterol. As esterification proceeds cholesterol esters accumulate within the hydrophobic core of the discoidal phospholipid bilayer transforming it into a spherical HDL particle. To investigate the change in apoA-I conformation as it adapts to a spherical surface, fluorescence resonance energy transfer studies were performed. Discoidal rHDL particles containing two lipid-bound apoA-I molecules were prepared with acceptor and donor fluorescent probes attached to cysteine residues located at specific positions. Fluorescence quenching was measured for probe combinations located within repeats 5 and 5 (residue 132), repeats 5 and 6 (residues 132 and 154), and repeats 6 and 6 (residue 154). Results from these experiments indicated that each of the 2 molecules of discoidal bound apoA-I exists in multiple conformations and support the concept of a "variable registry" rather than a "fixed helix-helix registry." Additionally, discoidal rHDL were transformed in vitro to core-containing particles by incubation with lecithin:cholesterol acyltransferase. Compositional analysis showed that core-containing particles contained 11% less phospholipid and 633% more cholesterol ester and a total of 3 apoA-I molecules per particle. Spherical particles showed a lowering of acceptor to donor probe quenching when compared with starting rHDL. Therefore, we conclude that as lipid-bound apoA-I adjusts from a discoidal to a spherical surface its intermolecular interactions are significantly reduced presumably to cover the increased surface area of the particle.
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Affiliation(s)
- Hui-Hua Li
- Department of Pathology, The Wake Forest University Baptist Medical Center, Winston-Salem, North Carolina 27157, USA
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Abstract
Apolipophorin III (ApoLp-III) from the Sphinx moth, Manduca sexta, is an 18kDa protein that binds reversibly to hydrophobic surfaces generated on metabolizing lipoprotein particles. It is comprised of amphipathic alpha-helices (H1-H5) organized in an up-and-down topology forming a helix bundle in the lipid-free state. Upon interaction with lipids, apoLp-III has been proposed to undergo a dramatic conformational change, involving helix bundle opening about putative hinge loops such that H1, H2 and H5 move away from H3 and H4. In the present study, we examine the relative spatial disposition of H1 and H5 on discoidal phospholipid complexes and spherical lipoproteins. Cysteine residues were engineered at position 8 in H1 and/or at position 138 in H5 in apoLp-III (which otherwise lacks Cys) yielding A8C-, A138C- and A8C/A138C-apoLp-III. Tethering of H1 and H5 by a disulfide bond between A8C and A138C abolished the ability of apoLp-III to transform phospholipid vesicles to discoidal particles, or to interact with lipoproteins, demonstrating that these helices are required to reposition during lipid interaction. Site-specific labeling of A8C/A138C-apoLp-III with N-(1-pyrene)maleimide in the lipid-free state resulted in intramolecular pyrene "excimer" fluorescence emission indicative of spatial proximity between these sites. Upon association with dimyristoylphosphatidylcholine (DMPC) discoidal complexes, the intramolecular excimer was replaced by intermolecular excimer fluorescence due to proximity between pyrene moieties on A8C and A138C in neighboring apoLp-III molecules on the discoidal particle. No excimer emission was observed in the case of pyrene-A8C-apoLp-III/DMPC or pyrene-A138C-apoLp-III/DMPC complexes. However, equimolar mixing of the two labeled single-cysteine mutants prior to disc formation resulted in excimer emission. In addition, intramolecular pyrene excimer formation was diminished upon binding of pyrene-A8C/A138C-apoLp-III to spherical lipoproteins. The data are consistent with repositioning of H1 away from H5 upon encountering a lipid surface, resulting in an extended conformation of apoLp-III that circumscribes the discoidal bilayer particle.
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Affiliation(s)
- Daisy Sahoo
- Department of Biochemistry, University of Alberta, Edmonton, Alta, Canada
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