151
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Huang R, Silva RAGD, Jerome WG, Kontush A, Chapman MJ, Curtiss LK, Hodges TJ, Davidson WS. Apolipoprotein A-I structural organization in high-density lipoproteins isolated from human plasma. Nat Struct Mol Biol 2011; 18:416-22. [PMID: 21399642 PMCID: PMC3079355 DOI: 10.1038/nsmb.2028] [Citation(s) in RCA: 169] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Accepted: 12/15/2010] [Indexed: 12/31/2022]
Abstract
High density lipoproteins (HDL) mediate cholesterol transport and protection from cardiovascular disease. Although synthetic HDLs have been studied for 30 years, the structure of human plasma-derived HDL, and its major protein apolipoprotein (apo)A-I, is unknown. We separated normal human HDL into 5 density subfractions and then further isolated those containing predominantly apoA-I (LpA-I). Using cross-linking chemistry and mass spectrometry, we found that apoA-I adopts a structural framework in these particles that closely mirrors that in synthetic HDL. We adapted established structural models for synthetic HDL to generate the first detailed models of authentic human plasma HDL in which apoA-I adopts a symmetrical cage-like structure. The models suggest that HDL particle size is modulated via a twisting motion of the resident apoA-I molecules. This understanding offers insights into how apoA-I structure modulates HDL function and its interactions with other apolipoproteins.
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Affiliation(s)
- Rong Huang
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio, USA
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152
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Jones MK, Gu F, Catte A, Li L, Segrest JP. "Sticky" and "promiscuous", the yin and yang of apolipoprotein A-I termini in discoidal high-density lipoproteins: a combined computational-experimental approach. Biochemistry 2011; 50:2249-63. [PMID: 21329368 DOI: 10.1021/bi101301g] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Apolipoprotein (apo) A-I-containing lipoproteins in the form of high-density lipoproteins (HDL) are inversely correlated with atherosclerosis. Because HDL is a soft form of condensed matter easily deformable by thermal fluctuations, the molecular mechanisms for HDL remodeling are not well understood. A promising approach to understanding HDL structure and dynamics is molecular dynamics (MD). In the present study, two computational strategies, MD simulated annealing (MDSA) and MD temperature jump, were combined with experimental particle reconstitution to explore molecular mechanisms for phospholipid- (PL-) rich HDL particle remodeling. The N-terminal domains of full-length apoA-I were shown to be "sticky", acting as a molecular latch largely driven by salt bridges, until, at a critical threshold of particle size, the associated domains released to expose extensive hydrocarbon regions of the PL to solvent. The "sticky" N-termini also associate with other apoA-I domains, perhaps being involved in N-terminal loops suggested by other laboratories. Alternatively, the overlapping helix 10 C-terminal domains of apoA-I were observed to be extremely mobile or "promiscuous", transiently exposing limited hydrocarbon regions of PL. Based upon these models and reconstitution studies, we propose that separation of the N-terminal domains, as particles exceed a critical size, triggers fusion between particles or between particles and membranes, while the C-terminal domains of apoA-I drive the exchange of polar lipids down concentration gradients between particles. This hypothesis has significant biological relevance since lipid exchange and particle remodeling are critically important processes during metabolism of HDL particles at every step in the antiatherogenic process of reverse cholesterol transport.
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Affiliation(s)
- Martin K Jones
- Department of Medicine and Atherosclerosis Research Unit, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
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153
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Wu Z, Gogonea V, Lee X, May RP, Pipich V, Wagner MA, Undurti A, Tallant TC, Baleanu-Gogonea C, Charlton F, Ioffe A, DiDonato JA, Rye KA, Hazen SL. The low resolution structure of ApoA1 in spherical high density lipoprotein revealed by small angle neutron scattering. J Biol Chem 2011; 286:12495-508. [PMID: 21292766 DOI: 10.1074/jbc.m110.209130] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Spherical high density lipoprotein (sHDL), a key player in reverse cholesterol transport and the most abundant form of HDL, is associated with cardiovascular diseases. Small angle neutron scattering with contrast variation was used to determine the solution structure of protein and lipid components of reconstituted sHDL. Apolipoprotein A1, the major protein of sHDL, forms a hollow structure that cradles a central compact lipid core. Three apoA1 chains are arranged within the low resolution structure of the protein component as one of three possible global architectures: (i) a helical dimer with a hairpin (HdHp), (ii) three hairpins (3Hp), or (iii) an integrated trimer (iT) in which the three apoA1 monomers mutually associate over a portion of the sHDL surface. Cross-linking and mass spectrometry analyses help to discriminate among the three molecular models and are most consistent with the HdHp overall architecture of apoA1 within sHDL.
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Affiliation(s)
- Zhiping Wu
- Department of Cell Biology, Center for Cardiovascular Diagnostics and Prevention, Cleveland Clinic, Cleveland, OH 44195, USA
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154
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Bricarello DA, Smilowitz JT, Zivkovic AM, German JB, Parikh AN. Reconstituted lipoprotein: a versatile class of biologically-inspired nanostructures. ACS NANO 2011; 5:42-57. [PMID: 21182259 DOI: 10.1021/nn103098m] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
One of biology's most pervasive nanostructures, the phospholipid membrane, represents an ideal scaffold for a host of nanotechnology applications. Whether engineering biomimetic technologies or designing therapies to interface with the cell, this adaptable membrane can provide the necessary molecular-level control of membrane-anchored proteins, glycopeptides, and glycolipids. If appropriately prepared, these components can replicate in vitro or influence in vivo essential living processes such as signal transduction, mass transport, and chemical or energy conversion. To satisfy these requirements, a lipid-based, synthetic nanoscale architecture with molecular-level tunability is needed. In this regard, discrete lipid particles, including reconstituted high density lipoprotein (HDL), have emerged as a versatile and elegant solution. Structurally diverse, native biological HDLs exist as discoidal lipid bilayers of 5-8 nm diameter and lipid monolayer-coated spheres 10-15 nm in diameter, all belted by a robust scaffolding protein. These supramolecular assemblies can be reconstituted using simple self-assembly methods to incorporate a broad range of amphipathic molecular constituents, natural or artificial, and provide a generic platform for stabilization and transport of amphipathic and hydrophobic elements capable of docking with targets at biological or inorganic surfaces. In conjunction with top-down or bottom-up engineering approaches, synthetic HDL can be designed, arrayed, and manipulated for a host of applications including biochemical analyses and fundamental studies of molecular structure. Also highly biocompatible, these assemblies are suitable for medical diagnostics and therapeutics. The collection of efforts reviewed here focuses on laboratory methods by which synthetic HDLs are produced, the advantages conferred by their nanoscopic dimension, and current and emerging applications.
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Affiliation(s)
- Daniel A Bricarello
- Department of Applied Science, University of California-Davis, Davis, California 95616, United States
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155
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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] [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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156
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Bashtovyy D, Jones MK, Anantharamaiah GM, Segrest JP. Sequence conservation of apolipoprotein A-I affords novel insights into HDL structure-function. J Lipid Res 2010; 52:435-50. [PMID: 21159667 DOI: 10.1194/jlr.r012658] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We performed alignment of apolipoprotein A-I (apoA-I) sequences from 31 species of animals. We found there is specific conservation of salt bridge-forming residues in the first 30 residues of apoA-I and general conservation of a variety of residue types in the central domain, helix 2/3 to helix 7/8. In the lipid-associating domain, helix 7 and helix 10 are the most and least conserved helixes, respectively. Furthermore, eight residues are completely conserved: P66, R83, P121, E191, and P220, and three of seven Tyr residues in human apoA-I, Y18, Y115, and Y192, are conserved. Residue Y18 appears to be important for assembly of HDL. E191-Y192 represents the only completely conserved pair of adjacent residues in apoA-I; Y192 is a preferred target for site-specific oxidative modification within atheroma, and molecular dynamic simulations suggest that the conserved pair E191-Y192 is in a solvent-exposed loop-helix-loop. Molecular dynamics testing of human apoA-I showed that M112 and M148 interact with Y115, a microenvironment unique to human apoA-I. Finally, conservation of Arg residues in the α11/3 helical wheel position 7 supports several possibilities: interactions with adjacent phospholipid molecules and/or oxidized lipids and/or binding of antioxidant enzymes through cation-π orbital interactions. We conclude that sequence alignment of apoA-I provides unique insights into apoA-I structure-function relationship.
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Affiliation(s)
- Denys Bashtovyy
- Department of Medicine, Atherosclerosis Research Unit, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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157
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Lagerstedt JO, Cavigiolio G, Budamagunta MS, Pagani I, Voss JC, Oda MN. Structure of apolipoprotein A-I N terminus on nascent high density lipoproteins. J Biol Chem 2010; 286:2966-75. [PMID: 21047795 DOI: 10.1074/jbc.m110.163097] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apolipoprotein A-I (apoA-I) is the major protein component of high density lipoproteins (HDL) and a critical element of cholesterol metabolism. To better elucidate the role of the apoA-I structure-function in cholesterol metabolism, the conformation of the apoA-I N terminus (residues 6-98) on nascent HDL was examined by electron paramagnetic resonance (EPR) spectroscopic analysis. A series of 93 apoA-I variants bearing single nitroxide spin label at positions 6-98 was reconstituted onto 9.6-nm HDL particles (rHDL). These particles were subjected to EPR spectral analysis, measuring regional flexibility and side chain solvent accessibility. Secondary structure was elucidated from side-chain mobility and molecular accessibility, wherein two major α-helical domains were localized to residues 6-34 and 50-98. We identified an unstructured segment (residues 35-39) and a β-strand (residues 40-49) between the two helices. Residues 14, 19, 34, 37, 41, and 58 were examined by EPR on 7.8, 8.4, and 9.6 nm rHDL to assess the effect of particle size on the N-terminal structure. Residues 14, 19, and 58 showed no significant rHDL size-dependent spectral or accessibility differences, whereas residues 34, 37, and 41 displayed moderate spectral changes along with substantial rHDL size-dependent differences in molecular accessibility. We have elucidated the secondary structure of the N-terminal domain of apoA-I on 9.6 nm rHDL (residues 6-98) and identified residues in this region that are affected by particle size. We conclude that the inter-helical segment (residues 35-49) plays a role in the adaptation of apoA-I to the particle size of HDL.
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Affiliation(s)
- Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
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158
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Kijac A, Shih AY, Nieuwkoop AJ, Schulten K, Sligar SG, Rienstra CM. Lipid-protein correlations in nanoscale phospholipid bilayers determined by solid-state nuclear magnetic resonance. Biochemistry 2010; 49:9190-8. [PMID: 20804175 PMCID: PMC3136391 DOI: 10.1021/bi1013722] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nanodiscs are examples of discoidal nanoscale lipid-protein particles that have been extremely useful for the biochemical and biophysical characterization of membrane proteins. They are discoidal lipid bilayer fragments encircled and stabilized by two amphipathic helical proteins named membrane scaffolding protein (MSP), ~10 nm in size. Nanodiscs are homogeneous, easily prepared with reproducible success, amenable to preparations with a variety of lipids, and stable over a range of temperatures. Here we present solid-state nuclear magnetic resonance (SSNMR) studies on lyophilized, rehydrated POPC Nanodiscs prepared with uniformly (13)C-, (15)N-labeled MSP1D1 (Δ1-11 truncated MSP). Under these conditions, by SSNMR we directly determine the gel-to-liquid crystal lipid phase transition to be at 3 ± 2 °C. Above this phase transition, the lipid (1)H signals have slow transverse relaxation, enabling filtering experiments as previously demonstrated for lipid vesicles. We incorporate this approach into two- and three-dimensional heteronuclear SSNMR experiments to examine the MSP1D1 residues interfacing with the lipid bilayer. These (1)H-(13)C and (1)H-(13)C-(13)C correlation spectra are used to identify and quantify the number of lipid-correlated and solvent-exposed residues by amino acid type, which furthermore is compared with molecular dynamics studies of MSP1D1 in Nanodiscs. This study demonstrates the utility of SSNMR experiments with Nanodiscs for examining lipid-protein interfaces and has important applications for future structural studies of membrane proteins in physiologically relevant formulations.
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Affiliation(s)
- Aleksandra Kijac
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Amy Y. Shih
- Beckman Institute for Advanced Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Andrew J. Nieuwkoop
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Klaus Schulten
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Beckman Institute for Advanced Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Stephen G. Sligar
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Beckman Institute for Advanced Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Chad M. Rienstra
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Beckman Institute for Advanced Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
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159
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Abstract
Schizophrenia is one of the most severe psychiatric disorders affecting 1% of the world population. There is yet no empirical method to validate the diagnosis of the disease. The identification of an underlying molecular alteration could lead to an improved disease understanding and may yield an objective panel of biomarkers to aid in the diagnosis of this devastating disease. Presented is the largest reported liquid chromatography-mass spectrometry-based proteomic profiling study investigating serum samples taken from first-onset drug-naive patients compared with samples collected from healthy volunteers. The results of this large-scale study are presented along with enzyme-linked immunosorbent assay-based validation data.
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160
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Rocco AG, Sensi C, Gianazza E, Calabresi L, Franceschini G, Sirtori CR, Eberini I. Structural and dynamic features of apolipoprotein A-I cysteine mutants, Milano and Paris, in synthetic HDL. J Mol Graph Model 2010; 29:406-14. [DOI: 10.1016/j.jmgm.2010.08.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 07/29/2010] [Accepted: 08/05/2010] [Indexed: 12/16/2022]
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161
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Vuorela T, Catte A, Niemelä PS, Hall A, Hyvönen MT, Marrink SJ, Karttunen M, Vattulainen I. Role of lipids in spheroidal high density lipoproteins. PLoS Comput Biol 2010; 6:e1000964. [PMID: 21060857 PMCID: PMC2965744 DOI: 10.1371/journal.pcbi.1000964] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 09/17/2010] [Indexed: 01/25/2023] Open
Abstract
We study the structure and dynamics of spherical high density lipoprotein (HDL) particles through coarse-grained multi-microsecond molecular dynamics simulations. We simulate both a lipid droplet without the apolipoprotein A-I (apoA-I) and the full HDL particle including two apoA-I molecules surrounding the lipid compartment. The present models are the first ones among computational studies where the size and lipid composition of HDL are realistic, corresponding to human serum HDL. We focus on the role of lipids in HDL structure and dynamics. Particular attention is paid to the assembly of lipids and the influence of lipid-protein interactions on HDL properties. We find that the properties of lipids depend significantly on their location in the particle (core, intermediate region, surface). Unlike the hydrophobic core, the intermediate and surface regions are characterized by prominent conformational lipid order. Yet, not only the conformations but also the dynamics of lipids are found to be distinctly different in the different regions of HDL, highlighting the importance of dynamics in considering the functionalization of HDL. The structure of the lipid droplet close to the HDL-water interface is altered by the presence of apoA-Is, with most prominent changes being observed for cholesterol and polar lipids. For cholesterol, slow trafficking between the surface layer and the regimes underneath is observed. The lipid-protein interactions are strongest for cholesterol, in particular its interaction with hydrophobic residues of apoA-I. Our results reveal that not only hydrophobicity but also conformational entropy of the molecules are the driving forces in the formation of HDL structure. The results provide the first detailed structural model for HDL and its dynamics with and without apoA-I, and indicate how the interplay and competition between entropy and detailed interactions may be used in nanoparticle and drug design through self-assembly.
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Affiliation(s)
- Timo Vuorela
- Department of Physics, Tampere University of Technology, Tampere, Finland
| | - Andrea Catte
- Department of Physics, Tampere University of Technology, Tampere, Finland
- Department of Medicine and Center for Computational and Structural Biology, University of Alabama, Birmingham, Alabama, United States of America
| | | | - Anette Hall
- Department of Physics, Tampere University of Technology, Tampere, Finland
| | | | - Siewert-Jan Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Mikko Karttunen
- Department of Applied Mathematics, The University of Western Ontario, London, Ontario, Canada
| | - Ilpo Vattulainen
- Department of Physics, Tampere University of Technology, Tampere, Finland
- Department of Applied Physics, Aalto University School of Science and Technology, Espoo, Finland
- MEMPHYS–Center of Biomembrane Physics, Physics Department, University of Southern Denmark, Odense M, Denmark
- * E-mail:
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162
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Miyazaki M, Tajima Y, Handa T, Nakano M. Static and Dynamic Characterization of Nanodiscs with Apolipoprotein A-I and Its Model Peptide. J Phys Chem B 2010; 114:12376-82. [DOI: 10.1021/jp102074b] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Masakazu Miyazaki
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yoko Tajima
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Tetsurou Handa
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Minoru Nakano
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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163
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Bhat S, Sorci-Thomas MG, Calabresi L, Samuel MP, Thomas MJ. Conformation of dimeric apolipoprotein A-I milano on recombinant lipoprotein particles. Biochemistry 2010; 49:5213-24. [PMID: 20524691 DOI: 10.1021/bi1003734] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Apolipoprotein A-I Milano (apoA-I(Milano)) is a naturally occurring human mutation of wild-type apolipoprotein A-I (apoA-I(WT)) having cystine substituted for arginine(173). Two molecules of apo-I(WT) form disks with phospholipid having a defined relationship between the apoA-I(WT) molecules. ApoA-I(Milano) forms cystine homodimers that would not allow the protein to adopt the conformation reported for apoA-I(WT). The conformational constraints for dimeric apoA-I(Milano) recombinant high-density lipoprotein (rHDL) disks made with phospholipid were deduced from a combination of chemical cross-linking and mass spectrometry. Lysine-selective homobifunctional cross-linkers were reacted with homogeneous rHDL having diameters of 78 and 125 A. After reduction, cross-linked apoA-I(Milano) was separated from monomeric apoprotein by gel electrophoresis and then subjected to in-gel trypsin digest. Cross-linked peptides were confirmed by MS/MS sequencing. The cross-links provided distance constraints that were used to refine models of lipid-bound dimeric apoA-I(Milano). These studies suggest that a single dimeric apoA-I(Milano) on 78 A diameter rHDL girdles the edge of a phospholipid disk assuming a "belt" conformation similar to the "belt" region of apoA-I(WT) on rHDL. However, the C-terminal end of dimeric apoA-I(Milano) wraps around the periphery of the particle to shield the fatty acid chains from water rather than folding back onto the "belt" as does apoA-I(WT). The two apoA-I(Milano) dimers on a 125 A diameter rHDL do not encircle the periphery of a phospholipid disk but appear to reside on the surface of a laminar micelle.
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Affiliation(s)
- Shaila Bhat
- Department of Pathology, Center for Lipid Science, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, North Carolina 27157, USA
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164
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Shao B, Oda MN, Oram JF, Heinecke JW. Myeloperoxidase: an oxidative pathway for generating dysfunctional high-density lipoprotein. Chem Res Toxicol 2010; 23:447-54. [PMID: 20043647 DOI: 10.1021/tx9003775] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Accumulation of low-density lipoprotein (LDL)-derived cholesterol by artery wall macrophages triggers atherosclerosis, the leading cause of cardiovascular disease. Conversely, high-density lipoprotein (HDL) retards atherosclerosis by promoting cholesterol efflux from macrophages by the membrane-associated ATP-binding cassette transporter A1 (ABCA1) pathway. HDL has been proposed to lose its cardioprotective effects in subjects with atherosclerosis, but the underlying mechanisms are poorly understood. One potential pathway involves oxidative damage by myeloperoxidase (MPO), a heme enzyme secreted by human artery wall macrophages. We used mass spectrometry to demonstrate that HDL isolated from patients with established cardiovascular disease contains elevated levels of 3-chlorotyrosine and 3-nitrotyrosine, two characteristic products of MPO. When apolipoprotein A-I (apoA-I), the major HDL protein, was oxidized by MPO, its ability to promote cellular cholesterol efflux by ABCA1 was impaired. Moreover, oxidized apoA-I was unable to activate lecithin:cholesterol acyltransferase (LCAT), which rapidly converts free cholesterol to cholesteryl ester, a critical step in HDL maturation. Biochemical studies implicated tyrosine chlorination and methionine oxygenation in the loss of ABCA1 and LCAT activity by oxidized apoA-I. Oxidation of specific residues in apoA-I inhibited two key steps in cholesterol efflux from macrophages, raising the possibility that MPO initiates a pathway for generating dysfunctional HDL in humans.
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Affiliation(s)
- Baohai Shao
- Department of Medicine, University of Washington, 815 Mercer Street, Seattle, Washington 98109, USA.
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165
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Fukuda M, Nakano M, Miyazaki M, Handa T. Thermodynamic and Kinetic Stability of Discoidal High-Density Lipoprotein Formation from Phosphatidylcholine/Apolipoprotein A-I Mixture. J Phys Chem B 2010; 114:8228-34. [DOI: 10.1021/jp101071t] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Masakazu Fukuda
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501
| | - Minoru Nakano
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501
| | - Masakazu Miyazaki
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501
| | - Tetsurou Handa
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501
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166
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Walshaw J, Gillespie MD, Kelemen GH. A novel coiled-coil repeat variant in a class of bacterial cytoskeletal proteins. J Struct Biol 2010; 170:202-15. [DOI: 10.1016/j.jsb.2010.02.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 02/06/2010] [Accepted: 02/15/2010] [Indexed: 10/19/2022]
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167
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Yetukuri L, Söderlund S, Koivuniemi A, Seppänen-Laakso T, Niemelä PS, Hyvönen M, Taskinen MR, Vattulainen I, Jauhiainen M, Oresic M. Composition and lipid spatial distribution of HDL particles in subjects with low and high HDL-cholesterol. J Lipid Res 2010; 51:2341-51. [PMID: 20431113 DOI: 10.1194/jlr.m006494] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A low level of high density lipoprotein cholesterol (HDL-C) is a powerful risk factor for cardiovascular disease. However, despite the reported key role of apolipo-proteins, specifically, apoA-I, in HDL metabolism, lipid molecular composition of HDL particles in subjects with high and low HDL-C levels is currently unknown. Here lipidomics was used to study HDL derived from well-characterized high and low HDL-C subjects. Low HDL-C subjects had elevated triacylglycerols and diminished lysophosphatidylcholines and sphingomyelins. Using information about the lipid composition of HDL particles in these two groups, we reconstituted HDL particles in silico by performing large-scale molecular dynamics simulations. In addition to confirming the measured change in particle size, we found that the changes in lipid composition also induced specific spatial distributions of lipids within the HDL particles, including a higher amount of triacylglycerols at the surface of HDL particles in low HDL-C subjects. Our findings have important implications for understanding HDL metabolism and function. For the first time we demonstrate the power of combining molecular profiling of lipoproteins with dynamic modeling of lipoprotein structure.
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168
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Cavigiolio G, Geier EG, Shao B, Heinecke JW, Oda MN. Exchange of apolipoprotein A-I between lipid-associated and lipid-free states: a potential target for oxidative generation of dysfunctional high density lipoproteins. J Biol Chem 2010; 285:18847-57. [PMID: 20385548 DOI: 10.1074/jbc.m109.098434] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
An important event in cholesterol metabolism is the efflux of cellular cholesterol by apolipoprotein A-I (apoA-I), the major protein of high density lipoproteins (HDL). Lipid-free apoA-I is the preferred substrate for ATP-binding cassette A1, which promotes cholesterol efflux from macrophage foam cells in the arterial wall. However, the vast majority of apoA-I in plasma is associated with HDL, and the mechanisms for the generation of lipid-free apoA-I remain poorly understood. In the current study, we used fluorescently labeled apoA-I that exhibits a distinct fluorescence emission spectrum when in different states of lipid association to establish the kinetics of apoA-I transition between the lipid-associated and lipid-free states. This approach characterized the spontaneous and rapid exchange of apoA-I between the lipid-associated and lipid-free states. In contrast, the kinetics of apoA-I exchange were significantly reduced when apoA-I on HDL was cross-linked with a bi-functional reagent or oxidized by myeloperoxidase. Our observations support the hypothesis that oxidative damage to apoA-I by myeloperoxidase limits the ability of apoA-I to be liberated in a lipid-free form from HDL. This impairment of apoA-I exchange reaction may be a trait of dysfunctional HDL contributing to reduced ATP-binding cassette A1-mediated cholesterol efflux and atherosclerosis.
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Affiliation(s)
- Giorgio Cavigiolio
- Children's Hospital Oakland Research Institute, Oakland, California 94609, USA
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169
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Murakami T, Tsuchida K, Hashida M, Imahori H. Size control of lipid-based drug carrier by drug loading. MOLECULAR BIOSYSTEMS 2010; 6:789-91. [DOI: 10.1039/c001442g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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170
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Jones MK, Catte A, Li L, Segrest JP. Dynamics of activation of lecithin:cholesterol acyltransferase by apolipoprotein A-I. Biochemistry 2009; 48:11196-210. [PMID: 19860440 DOI: 10.1021/bi901242k] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The product of transesterification of phospholipid acyl chains and unesterified cholesterol (UC) by the enzyme lecithin:cholesterol acyltransferase (LCAT) is cholesteryl ester (CE). Activation of LCAT by apolipoprotein (apo) A-I on nascent (discoidal) high-density lipoproteins (HDL) is essential for formation of mature (spheroidal) HDL during the antiatherogenic process of reverse cholesterol transport. Here we report all-atom and coarse-grained (CG) molecular dynamics (MD) simulations of HDL particles that have major implications for mechanisms of LCAT activation. Both the all-atom and CG simulations provide support for a model in which the helix 5/5 domains of apoA-I create an amphipathic "presentation tunnel" that exposes methyl ends of acyl chains at the bilayer center to solvent. Further, CG simulations show that UC also becomes inserted with high efficiency into the amphipathic presentation tunnel with its hydroxyl moiety (UC-OH) exposed to solvent; these results are consistent with trajectory analyses of the all-atom simulations showing that UC is being concentrated in the vicinity of the presentation tunnel. Finally, consistent with known product inhibition of CE-rich HDL by CE, CG simulations of CE-rich spheroidal HDL indicate partial blockage of the amphipathic presentation tunnel by CE. These results lead us to propose the following working hypothesis. After attachment of LCAT to discoidal HDL, the helix 5/5 domains in apoA-I form amphipathic presentation tunnels for migration of hydrophobic acyl chains and amphipathic UC from the bilayer to the phospholipase A2-like and esterification active sites of LCAT, respectively. This hypothesis is currently being tested by site-directed mutagenesis.
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Affiliation(s)
- Martin K Jones
- Department of Medicine and Atherosclerosis Research Unit, University ofAlabama, Birmingham, Alabama 35294, USA
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171
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Wu Z, Gogonea V, Lee X, Wagner MA, Li XM, Huang Y, Undurti A, May RP, Haertlein M, Moulin M, Gutsche I, Zaccai G, DiDonato JA, Hazen SL. Double superhelix model of high density lipoprotein. J Biol Chem 2009; 284:36605-36619. [PMID: 19812036 DOI: 10.1074/jbc.m109.039537] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
High density lipoprotein (HDL), the carrier of so-called "good" cholesterol, serves as the major athero-protective lipoprotein and has emerged as a key therapeutic target for cardiovascular disease. We applied small angle neutron scattering (SANS) with contrast variation and selective isotopic deuteration to the study of nascent HDL to obtain the low resolution structure in solution of the overall time-averaged conformation of apolipoprotein AI (apoA-I) versus the lipid (acyl chain) core of the particle. Remarkably, apoA-I is observed to possess an open helical shape that wraps around a central ellipsoidal lipid phase. Using the low resolution SANS shapes of the protein and lipid core as scaffolding, an all-atom computational model for the protein and lipid components of nascent HDL was developed by integrating complementary structural data from hydrogen/deuterium exchange mass spectrometry and previously published constraints from multiple biophysical techniques. Both SANS data and the new computational model, the double superhelix model, suggest an unexpected structural arrangement of protein and lipids of nascent HDL, an anti-parallel double superhelix wrapped around an ellipsoidal lipid phase. The protein and lipid organization in nascent HDL envisages a potential generalized mechanism for lipoprotein biogenesis and remodeling, biological processes critical to sterol and lipid transport, organismal energy metabolism, and innate immunity.
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Affiliation(s)
- Zhiping Wu
- Department of Cell Biology, Cleveland Clinic, Cleveland, Ohio 44195; Center for Cardiovascular Diagnostics and Prevention, Cleveland Clinic, Cleveland, Ohio 44195
| | - Valentin Gogonea
- Department of Cell Biology, Cleveland Clinic, Cleveland, Ohio 44195; Department of Chemistry, Cleveland State University, Cleveland, Ohio 44115
| | - Xavier Lee
- Department of Cell Biology, Cleveland Clinic, Cleveland, Ohio 44195; Center for Cardiovascular Diagnostics and Prevention, Cleveland Clinic, Cleveland, Ohio 44195
| | - Matthew A Wagner
- Department of Cell Biology, Cleveland Clinic, Cleveland, Ohio 44195; Center for Cardiovascular Diagnostics and Prevention, Cleveland Clinic, Cleveland, Ohio 44195
| | - Xin-Min Li
- Department of Cell Biology, Cleveland Clinic, Cleveland, Ohio 44195; Center for Cardiovascular Diagnostics and Prevention, Cleveland Clinic, Cleveland, Ohio 44195
| | - Ying Huang
- Department of Cell Biology, Cleveland Clinic, Cleveland, Ohio 44195; Center for Cardiovascular Diagnostics and Prevention, Cleveland Clinic, Cleveland, Ohio 44195
| | - Arundhati Undurti
- Department of Cell Biology, Cleveland Clinic, Cleveland, Ohio 44195; Center for Cardiovascular Diagnostics and Prevention, Cleveland Clinic, Cleveland, Ohio 44195
| | - Roland P May
- Institut Laue-Langevin, 6 Rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9, France
| | - Michael Haertlein
- Institut Laue-Langevin, 6 Rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9, France
| | - Martine Moulin
- Institut Laue-Langevin, 6 Rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9, France
| | - Irina Gutsche
- Unit of Virus-Host Interaction, Unité Mixte de Recherche 5233 Université Joseph Fourier-European Molecular Biology Laboratory-CNRS, 6 Rue Jules Horowitz, BP 181, 38042 Grenoble Cedex 9, France
| | - Giuseppe Zaccai
- Institut Laue-Langevin, 6 Rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9, France; Institut de Biologie Structurale, Commissariat à l'Energie Atomique-CNRS-Université Joseph Fourier, 38027 Grenoble, France
| | - Joseph A DiDonato
- Department of Cell Biology, Cleveland Clinic, Cleveland, Ohio 44195; Center for Cardiovascular Diagnostics and Prevention, Cleveland Clinic, Cleveland, Ohio 44195
| | - Stanley L Hazen
- Department of Cell Biology, Cleveland Clinic, Cleveland, Ohio 44195; Center for Cardiovascular Diagnostics and Prevention, Cleveland Clinic, Cleveland, Ohio 44195; Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, Ohio 44195.
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172
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Shin JY, Shin JI, Kim JS, Yang YS, Hwang Y, Yang JS, Shin D, Seo JH, Jin YS, Park YC, Hwang JS, Kweon DH. Assembly of Coenzyme Q10 nanostructure resembling nascent discoidal high density lipoprotein particle. Biochem Biophys Res Commun 2009; 388:217-21. [DOI: 10.1016/j.bbrc.2009.07.140] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 07/27/2009] [Indexed: 01/19/2023]
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173
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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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174
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Rocco AG, Gianazza E, Calabresi L, Sensi C, Franceschini G, Sirtori CR, Eberini I. Structural features and dynamics properties of human apolipoprotein A-I in a model of synthetic HDL. J Mol Graph Model 2009; 28:305-12. [PMID: 19740687 DOI: 10.1016/j.jmgm.2009.08.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Revised: 08/14/2009] [Accepted: 08/18/2009] [Indexed: 10/20/2022]
Abstract
High-density lipoproteins (HDL) play a major role in the reverse transport of cholesterol and have antiatherogenic activities. Their major protein component is apolipoprotein (apo) A-I. While apoA-I amphipathic alpha-helix based secondary structure has been extensively investigated, for its lipid-bound tertiary structure only theoretical models have been proposed. In the past years, experimental approaches aimed at a direct visualization of HDL structure have been exploited, but data obtained through different microscopy techniques are conflicting and do not settle the issue. Here we present a 50 ns molecular dynamics simulation of a synthetic HDL containing two molecules of apoA-I and 101 of l-alpha-palmitoyl-oleoyl-phosphatidylcholine. Essential dynamics and structural property investigations suggest that the stabilization of the system is obtained through specific motions, whose driving forces are protein-phospholipid interactions. The most important are: the relative sliding of the two apoA-I molecules along their major axes, the relative rotation of the protein chains, and the out-of-plane deformation around proline hinges. The sliding and the out-of-plane deformation allow apoA-I to optimize its interactions with phospholipids, while the rotation is useful to maximize protein-protein salt bridges. The correspondence between computed parameters and their experimental counterparts contributes to validate our model and its dynamic behaviors. Our findings help in defining a molecular model for apoA-I contained in HDL and suggest a possible mechanism through which apoA-I can vary its diameter and accommodate different numbers of phospholipids during the metabolism of HDL.
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Affiliation(s)
- Alessandro Guerini Rocco
- Gruppo di Studio per la Proteomica e la Struttura delle Proteine, Dipartimento di Scienze Farmacologiche, Università degli Studi di Milano, 20133 Milano, Italy
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175
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Abstract
Abstract
A major challenge in the research on membrane-anchored and integral membrane protein complexes is to obtain these in a functionally active, water-soluble, and monodisperse form. This requires the incorporation of the membrane proteins into a native-like membrane or detergent micelle that mimics the properties of the original biological membrane. However, solubilization in detergents or reconstitution in liposomes or supported monolayers sometimes suffers from loss of activity and problematic analyses due to heterogeneity and aggregation. A developing technology termed nanodiscs exploits discoidal phospholipid bilayers encircled by a stabilizing amphipatic helical membrane scaffold protein to reconstitute membranes with integral proteins. After reconstitution, the membrane nanodisc is soluble, stable, and monodisperse. In the present review, we outline the biological inspiration for nanodiscs as discoidal high-density lipoproteins, the assembly and handling of nanodiscs, and finally their diverse biochemical applications. In our view, major advantages of nanodisc technology for integral membrane proteins is homogeneity, control of oligomerization state, access to both sides of the membrane, and control of lipids in the local membrane environment of the integral protein.
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176
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Cho KH. Biomedicinal implications of high-density lipoprotein: its composition, structure, functions, and clinical applications. BMB Rep 2009; 42:393-400. [DOI: 10.5483/bmbrep.2009.42.7.393] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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177
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Miyazaki M, Nakano M, Fukuda M, Handa T. Smaller Discoidal High-Density Lipoprotein Particles Form Saddle Surfaces, but Not Planar Bilayers. Biochemistry 2009; 48:7756-63. [DOI: 10.1021/bi900785x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Masakazu Miyazaki
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Minoru Nakano
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Masakazu Fukuda
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Tetsurou Handa
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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178
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HDL biogenesis and functions: role of HDL quality and quantity in atherosclerosis. Atherosclerosis 2009; 208:3-9. [PMID: 19595353 DOI: 10.1016/j.atherosclerosis.2009.05.034] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 05/01/2009] [Accepted: 05/24/2009] [Indexed: 12/16/2022]
Abstract
Coronary heart disease (CHD) is a leading cause of death in western societies. In the last few decades, a number of epidemiological studies have shown that a disproportion between atheroprotective and atherogenic lipoproteins in plasma is one of the most important contributors towards atherosclerosis and CHD. Thus, based on the classical view, reduced HDL cholesterol levels independently predict one's risk factor for developing cardiovascular disease, while elevated HDL levels protect from atherosclerosis. However, more recent studies have suggested that the relationship between HDL and cardiovascular risk is more complex and extends beyond the levels of HDL in plasma. These studies challenge the existing view on HDL and cardiovascular risk and trigger a discussion as to whether low HDL is a causal effect for the development of heart disease. In this article we provide a review of the current literature on the biogenesis of HDL and its proposed functions in atheroprotection. In addition, we discuss the significance of both HDL quality and quantity in assessing cardiovascular risk.
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179
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Nakano M, Fukuda M, Kudo T, Miyazaki M, Wada Y, Matsuzaki N, Endo H, Handa T. Static and Dynamic Properties of Phospholipid Bilayer Nanodiscs. J Am Chem Soc 2009; 131:8308-12. [DOI: 10.1021/ja9017013] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Minoru Nakano
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, and Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Masakazu Fukuda
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, and Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Takayuki Kudo
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, and Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Masakazu Miyazaki
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, and Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Yusuke Wada
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, and Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Naoya Matsuzaki
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, and Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Hitoshi Endo
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, and Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Tetsurou Handa
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, and Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
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180
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Towards a microarray of functional membrane proteins: Assembly of a surface-attachable, membrane-protein-anchored membrane structure using apolipoprotein A-1. Enzyme Microb Technol 2009. [DOI: 10.1016/j.enzmictec.2008.10.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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181
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Alexander ET, Tanaka M, Kono M, Saito H, Rader DJ, Phillips MC. Structural and functional consequences of the Milano mutation (R173C) in human apolipoprotein A-I. J Lipid Res 2009; 50:1409-19. [PMID: 19318685 DOI: 10.1194/jlr.m800578-jlr200] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Carriers of the apolipoprotein A-I(Milano) (apoA-I(M)) variant, R173C, have reduced levels of plasma HDL but no increase in cardiovascular disease. Despite intensive study, it is not clear whether the removal of the arginine or the introduction of the cysteine is responsible for this altered functionality. We investigated this question using two engineered variations of the apoA-I(M) mutation: R173S apoA-I, similar to apoA-I(M) but incapable of forming a disulfide bond, and R173K apoA-I, a conservative mutation. Characterization of the lipid-free proteins showed that the order of stability was wild type approximately R173K>R173S>R173C. Compared with wild-type apoA-I, apoA-I(M) had a lower affinity for lipids, while R173S apoA-I displayed intermediate affinity. The in vivo effects of the apoA-I variants were measured by injecting apoA-I-expressing adeno-associated virus into apoA-I-null mice. Mice that expressed the R173S variant again showed an intermediate phenotype. Thus, both the loss of the arginine and its replacement by a cysteine contribute to the altered properties of apoA-I(M). The arginine is potentially involved in an intrahelical salt bridge with E169 that is disrupted by the loss of the positively charged arginine and repelled by the cysteine, destabilizing the helix bundle domain in the apoA-I molecule and modifying its lipid binding characteristics.
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Affiliation(s)
- Eric T Alexander
- Gastroenterology/Nutrition/Hepatology Division, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-4318, USA
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182
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Jones MK, Catte A, Patterson JC, Gu F, Chen J, Li L, Segrest JP. Thermal stability of apolipoprotein A-I in high-density lipoproteins by molecular dynamics. Biophys J 2009; 96:354-71. [PMID: 19167289 DOI: 10.1016/j.bpj.2008.09.041] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Accepted: 09/22/2008] [Indexed: 02/06/2023] Open
Abstract
Apolipoprotein (apo) A-I is an unusually flexible protein whose lipid-associated structure is poorly understood. Thermal denaturation, which is used to measure the global helix stability of high-density lipoprotein (HDL)-associated apoA-I, provides no information about local helix stability. Here we report the use of temperature jump molecular dynamics (MD) simulations to scan the per-residue helix stability of apoA-I in phospholipid-rich HDL. When three 20 ns MD simulations were performed at 500 K on each of two particles created by MD simulations at 310 K, bilayers remained intact but expanded by 40%, and total apoA-I helicity decreased from 95% to 72%. Of significance, the conformations of the overlapping N- and C-terminal domains of apoA-I in the particles were unusually mobile, exposing hydrocarbon regions of the phospholipid to solvent; a lack of buried interhelical salt bridges in the terminal domains correlated with increased mobility. Nondenaturing gradient gels show that 40% expansion of the phospholipid surface of 100:2 particles by addition of palmitoyloleoylphosphatidylcholine exceeds the threshold of particle stability. As a unifying hypothesis, we propose that the terminal domains of apoA-I are phospholipid concentration-sensitive molecular triggers for fusion/remodeling of HDL particles. Since HDL remodeling is necessary for cholesterol transport, our model for remodeling has substantial biomedical implications.
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Affiliation(s)
- Martin K Jones
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
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183
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Sorci-Thomas MG, Bhat S, Thomas MJ. Activation of lecithin:cholesterol acyltransferase by HDL ApoA-I central helices. CLINICAL LIPIDOLOGY 2009; 4:113-124. [PMID: 20582235 PMCID: PMC2891274 DOI: 10.2217/17584299.4.1.113] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Lecithin:cholesterol acyltransferase (LCAT) is an enzyme that first hydrolyzes the sn-2 position of phospholipids, preferentially a diacylphosphocholine, and then transfers the fatty acid to cholesterol to yield a cholesteryl ester. HDL ApoA-I is the principal catalytic activator for LCAT. Activity of LCAT on nascent or lipid-poor HDL particles composed of phospholipid, cholesterol and ApoA-I allows the maturation of HDL particles into lipid-rich spherical particles that contain a core of cholesteryl ester surrounded by phospholipid and ApoA-I on the surface. This article reviews the recent progress in elucidating structural aspects of the interaction between LCAT and ApoA-I. In the last decade, there has been considerable progress in understanding the structure of ApoA-I and the central helices 5, 6, and 7 that are known to activate LCAT. However, much less information has been forthcoming describing the 3D structure and conformation of LCAT required to catalyze two separate reactions within a single monomeric peptide.
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Affiliation(s)
- Mary G Sorci-Thomas
- Department of Pathology, Wake Forest University School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157-1016, USA, Tel.: +1 336 716 2147, Fax: +1 336 716 6279,
| | - Shaila Bhat
- Department of Pathology, Lipid Sciences Research Center, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA, Tel.: +1 336 716 6062, Fax: +1 336 716 6279,
| | - Michael J Thomas
- Department of Biochemistry, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA, Tel.: +1 336 716 2313, Fax: +1 336 716 6279,
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184
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Human apolipoprotein A-I binds amyloid-beta and prevents Abeta-induced neurotoxicity. Int J Biochem Cell Biol 2008; 41:1361-70. [PMID: 19130896 DOI: 10.1016/j.biocel.2008.12.003] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Revised: 11/27/2008] [Accepted: 12/08/2008] [Indexed: 01/03/2023]
Abstract
Aggregates of the amyloid-beta peptide (Abeta) play a central role in the pathogenesis of Alzheimer's disease (AD). Identification of proteins that physiologically bind Abeta and modulate its aggregation and neurotoxicity could lead to the development of novel disease-modifying approaches in AD. By screening a phage display peptide library for high affinity ligands of aggregated Abeta(1-42), we isolated a peptide homologous to a highly conserved amino acid sequence present in the N-terminus of apolipoprotein A-I (apoA-I). We show that purified human apoA-I and Abeta form non-covalent complexes and that interaction with apoA-I affects the morphology of amyloid aggregates formed by Abeta. Significantly, Abeta/apoA-I complexes were also detected in cerebrospinal fluid from AD patients. Interestingly, apoA-I and apoA-I-containing reconstituted high density lipoprotein particles protect hippocampal neuronal cultures from Abeta-induced oxidative stress and neurodegeneration. These results suggest that human apoA-I modulates Abeta aggregation and Abeta-induced neuronal damage and that the Abeta-binding domain in apoA-I may constitute a novel framework for the design of inhibitors of Abeta toxicity.
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185
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White CR, Datta G, Zhang Z, Gupta H, Garber DW, Mishra VK, Palgunachari MN, Handattu SP, Chaddha M, Anantharamaiah GM. HDL therapy for cardiovascular diseases: the road to HDL mimetics. Curr Atheroscler Rep 2008; 10:405-12. [PMID: 18706282 DOI: 10.1007/s11883-008-0063-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) are currently the drug of choice for the clinical management of elevated low-density lipoprotein (LDL) cholesterol. Although statin treatment provides an overall improvement in outcomes, clinical trial data reveal a significant number of cardiac events despite reaching targeted LDL levels. A low serum high-density lipoprotein (HDL) cholesterol level is an independent predictor of cardiovascular risk. Accordingly, there has been interest in determining whether HDL elevation, in addition to LDL lowering, further reduces risk in patients with coronary artery disease. Several commonly prescribed lipid-lowering therapies modestly raise HDL, but their use may be limited by the development of adverse reactions. Emerging data suggest that HDL quality and function may also be significantly reduced by atherosclerosis and other inflammatory diseases. The goal of this review is to discuss the current status of HDL therapeutics, with emphasis on a novel class of agent, the apolipoprotein A-I mimetic peptides, which improve the functional properties of HDL cholesterol.
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Affiliation(s)
- C Roger White
- Vascular Biology and Hypertension Program, University of Alabama, Birmingham, 1046 Zeigler Research Building, 703 South 19th Street, Birmingham, AL 35294, USA.
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186
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Fukuda M, Nakano M, Miyazaki M, Tanaka M, Saito H, Kobayashi S, Ueno M, Handa T. Conformational change of apolipoprotein A-I and HDL formation from model membranes under intracellular acidic conditions. J Lipid Res 2008; 49:2419-26. [DOI: 10.1194/jlr.m800287-jlr200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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187
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Relevance of the amino acid conversions L144R (Zaragoza) and L159P (Zavalla) in the apolipoprotein A-I binding site for haptoglobin. Biol Chem 2008; 389:1421-6. [DOI: 10.1515/bc.2008.156] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractThe high-density lipoprotein apolipoprotein A-I (ApoA-I) stimulates the enzyme lecithin-cholesterol acyltransferase (LCAT) in the reverse cholesterol transport pathway. Two ApoA-I variants, Zaragoza (L144R) and Zavalla (L159P), are associated with low levels of HDL-cholesterol but normal LCAT activity. Haptoglobin interacts with ApoA-I, impairing LCAT stimulation. Synthetic peptides matching the haptoglobin-binding site of native or variant ApoA-I (native, P2a; variants, Zav-pep and Zar-pep) bound haptoglobin with different activity: Zar-pep>P2a>Zav-pep. They also differently rescued LCATin vitroactivity in the presence of haptoglobin (P2a=Zar-pep>Zav-pep). Therefore, both amino acid conversions affect haptoglobin binding and LCAT regulation. We highlight the role of haptoglobin in LCAT regulation in subjects with ApoA-I variants.
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188
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Structure of apolipoprotein A-I in spherical high density lipoproteins of different sizes. Proc Natl Acad Sci U S A 2008; 105:12176-81. [PMID: 18719128 DOI: 10.1073/pnas.0803626105] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Spherical high density lipoproteins (HDL) predominate in human plasma. However, little information exists on the structure of the most common HDL protein, apolipoprotein (apo) A-I, in spheres vs. better studied discoidal forms. We produced spherical HDL by incubating reconstituted discoidal HDL with physiological plasma-remodeling enzymes and compared apoA-I structure in discs and spheres of comparable diameter (79-80 and 93-96 A). Using cross-linking chemistry and mass spectrometry, we determined that the general structural organization of apoA-I was overall similar between discs and spheres, regardless of diameter. This was the case despite the fact that the 93 A spheres contained three molecules of apoA-I per particle compared with only two in the discs. Thus, apoA-I adopts a consistent general structural framework in HDL particles-irrespective of shape, size and the number of apoA-Is present. Furthermore, a similar cross-linking pattern was demonstrated in HDL particles isolated from human serum. We propose the first experiment-based molecular model of apoA-I in spherical HDL particles. This model provides a new foundation for understanding how apoA-I structure modulates HDL function and metabolism.
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189
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Ramos S, Campos-Terán J, Mas-Oliva J, Nylander T, Castillo R. Forces between hydrophilic surfaces adsorbed with apolipoprotein AII alpha helices. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:8568-8575. [PMID: 18652418 DOI: 10.1021/la800348y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
To provide better understanding of how a protein secondary structure affects protein-protein and protein-surface interactions, forces between amphiphilic alpha-helical proteins (human apolipoprotein AII) adsorbed on a hydrophilic surface (mica) were measured using an interferometric surface force apparatus (SFA). Forces between surfaces with adsorbed layers of this protein are mainly composed of electrostatic double layer forces at large surface distances and of steric repulsive forces at small distances. We suggest that the amphiphilicity of the alpha-helix structure facilitates the formation of protein multilayers next to the mica surfaces. We found that protein-surface interaction is stronger than protein-protein interaction, probably due to the high negative charge density of the mica surface and the high positive charge of the protein at our experimental conditions. Ellipsometry was used to follow the adsorption kinetics of this protein on hydrophilic silica, and we observed that the adsorption rate is not only controlled by diffusion, but rather by the protein-surface interaction. Our results for dimeric apolipoprotein AII are similar to those we have reported for the monomeric apolipoprotein CI, which has a similar secondary structure but a different peptide sequence and net charge. Therefore, the observed force curves seem to be a consequence of the particular features of the amphiphilic alpha-helices.
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Affiliation(s)
- S Ramos
- Departamento de Procesos y Tecnologia, CNI, Universidad Autónoma Metropolitana-Cuajimalpa, Artificios 40, 60 Piso, DF, Mexico
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190
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Carnemolla R, Ren X, Biswas TK, Meredith SC, Reardon CA, Wang J, Getz GS. The specific amino acid sequence between helices 7 and 8 influences the binding specificity of human apolipoprotein A-I for high density lipoprotein (HDL) subclasses: a potential for HDL preferential generation. J Biol Chem 2008; 283:15779-88. [PMID: 18385132 PMCID: PMC2414305 DOI: 10.1074/jbc.m710244200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Revised: 04/01/2008] [Indexed: 02/02/2023] Open
Abstract
Humans have two major high density lipoprotein (HDL) sub-fractions, HDL(2) and HDL(3), whereas mice have a monodisperse HDL profile. Epidemiological evidence has suggested that HDL(2) is more atheroprotective; however, currently there is no direct experimental evidence to support this postulate. The amino acid sequence of apoA-I is a primary determinant of HDL subclass formation. The majority of the alpha-helical repeats in human apoA-I are proline-punctuated. A notable exception is the boundary between helices 7 and 8, which is located in the transitional segment between the stable N-terminal domain and the C-terminal hydrophobic domain. In this study we ask whether the substitution of a proline-containing sequence (PCS) separating other helices in human apoA-I for the non-proline-containing sequence (NPCS) between helices 7 and 8 (residues 184-190) influences HDL subclass association. The human apoA-I mutant with PCS2 replacing NPCS preferentially bound to HDL(2). In contrast, the mutant where PCS3 replaced NPCS preferentially associated with HDL(3). Thus, the specific amino acid sequence between helices 7 and 8 influences HDL subclass association. The wild-type and mutant proteins exhibited similar physicochemical properties except that the two mutants displayed greater lipid-associated stability versus wild-type human apoA-I. These results focus new attention on the influence of the boundary between helices 7 and 8 on the properties of apoA-I. The expression of these mutants in mice may result in the preferential generation of HDL(2) or HDL(3) and allow us to examine experimentally the anti-atherogenicity of the HDL subclasses.
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Affiliation(s)
- Ronald Carnemolla
- Department of Pathology and the
Committee of Molecular Metabolism and Nutrition,
The University of Chicago, Chicago, Illinois 60637 and the
Department of Biochemistry and Molecular
Biology, Wayne State University, Detroit, Michigan 48201
| | - Xuefeng Ren
- Department of Pathology and the
Committee of Molecular Metabolism and Nutrition,
The University of Chicago, Chicago, Illinois 60637 and the
Department of Biochemistry and Molecular
Biology, Wayne State University, Detroit, Michigan 48201
| | - Tapan K. Biswas
- Department of Pathology and the
Committee of Molecular Metabolism and Nutrition,
The University of Chicago, Chicago, Illinois 60637 and the
Department of Biochemistry and Molecular
Biology, Wayne State University, Detroit, Michigan 48201
| | - Stephen C. Meredith
- Department of Pathology and the
Committee of Molecular Metabolism and Nutrition,
The University of Chicago, Chicago, Illinois 60637 and the
Department of Biochemistry and Molecular
Biology, Wayne State University, Detroit, Michigan 48201
| | - Catherine A. Reardon
- Department of Pathology and the
Committee of Molecular Metabolism and Nutrition,
The University of Chicago, Chicago, Illinois 60637 and the
Department of Biochemistry and Molecular
Biology, Wayne State University, Detroit, Michigan 48201
| | - Jianjun Wang
- Department of Pathology and the
Committee of Molecular Metabolism and Nutrition,
The University of Chicago, Chicago, Illinois 60637 and the
Department of Biochemistry and Molecular
Biology, Wayne State University, Detroit, Michigan 48201
| | - Godfrey S. Getz
- Department of Pathology and the
Committee of Molecular Metabolism and Nutrition,
The University of Chicago, Chicago, Illinois 60637 and the
Department of Biochemistry and Molecular
Biology, Wayne State University, Detroit, Michigan 48201
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191
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Gangabadage CS, Zdunek J, Tessari M, Nilsson S, Olivecrona G, Wijmenga SS. Structure and Dynamics of Human Apolipoprotein CIII. J Biol Chem 2008; 283:17416-27. [DOI: 10.1074/jbc.m800756200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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192
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Thomas MJ, Bhat S, Sorci-Thomas MG. Three-dimensional models of HDL apoA-I: implications for its assembly and function. J Lipid Res 2008; 49:1875-83. [PMID: 18515783 DOI: 10.1194/jlr.r800010-jlr200] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The purpose of this review is to highlight recent advances toward the refinement of a three-dimensional structure for lipid-bound apolipoprotein A-I (apoA-I) on recombinant HDL. Recently, X-ray crystallography has yielded a new structure for full-length, lipid-free apoA-I. Although this approach has not yet been successful in solving the three-dimensional structure of lipid-bound apoA-I, analysis of the X-ray structures has been of immense help in the interpretation of structural data obtained from other methods that yield structural information. Recent studies emphasize the use of mass spectrometry to unambiguously identify cross-linked peptides or to quantify solvent accessibility using hydrogen-deuterium exchange. The combination of mass spectrometry, molecular modeling, molecular dynamic analysis, and small-angle X-ray diffraction has provided additional structural information on apoA-I folding that complements previous approaches.
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Affiliation(s)
- Michael J Thomas
- Department of Biochemistry, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
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193
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Gonzalez MC, Toledo JD, Tricerri MA, Garda HA. The central type Y amphipathic α-helices of apolipoprotein AI are involved in the mobilization of intracellular cholesterol depots. Arch Biochem Biophys 2008; 473:34-41. [DOI: 10.1016/j.abb.2008.02.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Revised: 02/14/2008] [Accepted: 02/16/2008] [Indexed: 01/14/2023]
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194
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Magi E, Liscio C, Pistarino E, Santamaria B, Di Carro M, Tiso M, Scaloni A, Renzone G, Cosulich ME. Interdisciplinary study for the evaluation of biochemical alterations on mussel Mytilus galloprovincialis exposed to a tributyltin-polluted area. Anal Bioanal Chem 2008; 391:671-8. [DOI: 10.1007/s00216-008-2055-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 03/04/2008] [Accepted: 03/05/2008] [Indexed: 11/30/2022]
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195
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Wool GD, Reardon CA, Getz GS. Apolipoprotein A-I mimetic peptide helix number and helix linker influence potentially anti-atherogenic properties. J Lipid Res 2008; 49:1268-83. [PMID: 18323574 DOI: 10.1194/jlr.m700552-jlr200] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We hypothesize that apolipoprotein A-I (apoA-I) mimetic peptides better mimicking the punctuated alpha-helical repeats of full-length apoA-I are more anti-inflammatory and anti-atherogenic. This study compares a monomeric apoA-I mimetic helix to three different tandem helix peptides in vitro: 4F (18 mer), 4F-proline-4F (37 mer, Pro), 4F-alanine-4F (37 mer, Ala), and 4F-KVEPLRA-4F [the human apoA-I 4/5 interhelical sequence (IHS), 43 mer]. All peptides cleared turbid lipid suspensions, with 4F being most effective. In contrast to lipid clearance, tandem peptides were more effective at remodeling mouse HDL. All four peptides displaced apoA-I and apoE from the HDL, leaving a larger particle containing apoA-II and peptide. Peptide-remodeled HDL particles show no deficit in ABCG1 cholesterol efflux despite the loss of the majority of apoA-I. Tandem peptides show greater ability to efflux cholesterol from lipid-loaded murine macrophages, compared with 4F. Although 4F inhibited oxidation of purified mouse LDL, the Ala tandem peptide increased oxidation. We compared several tandem 4F-based peptides with monomeric 4F in assays that correlated with suggested anti-inflammatory/anti-atherogenic pathways. Tandem 4F-based peptides, which better mimic full-length apoA-I, exceed monomeric 4F in HDL remodeling and cholesterol efflux but not LDL oxidation protection. In addition, apoA-I mimetic peptides may increase reverse cholesterol transport through both ABCA1 as well as ABCG1 pathways.
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Affiliation(s)
- Geoffrey D Wool
- The University of Chicago, Department of Pathology, Chicago, IL, USA
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196
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Rapid incorporation of functional rhodopsin into nanoscale apolipoprotein bound bilayer (NABB) particles. J Mol Biol 2008; 377:1067-81. [PMID: 18313692 DOI: 10.1016/j.jmb.2008.01.066] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 01/18/2008] [Accepted: 01/22/2008] [Indexed: 11/23/2022]
Abstract
Human apolipoprotein A-I (apo A-I) and its engineered constructs form discoidal lipid bilayers upon interaction with lipids in vitro. We now report the cloning, expression, and purification of apo A-I derived from zebrafish (Danio rerio), which combines with phospholipids to form similar discoidal bilayers and may prove to be superior to human apo A-I constructs for rapid reconstitution of seven-transmembrane helix receptors into nanoscale apolipoprotein bound bilayers (NABBs). We characterized NABBs by gel-filtration chromatography, native polyacrylamide gradient gel electrophoresis, UV-visible photobleaching difference spectroscopy, and fluorescence spectroscopy. We used electron microscopy to determine the stoichiometry and orientation of rhodopsin (rho)-containing NABBs prepared under various conditions and correlated stability and signaling efficiency of rho in NABBs with either one or two receptors. We discovered that the specific activity of G protein coupling for single rhos sequestered in individual NABBs was nearly identical with that of two rhos per NABB under conditions where stoichiometry and orientation could be inferred by electron microscopy imaging. Thermal stability of rho in NABBs was superior to that of rho in various commonly used detergents. We conclude that the NABB system using engineered zebrafish apo A-I is a native-like membrane mimetic system for G-protein-coupled receptors and discuss strategies for rapid incorporation of expressed membrane proteins into NABBs.
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197
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Shao B, Oda MN, Oram JF, Heinecke JW. Myeloperoxidase: an inflammatory enzyme for generating dysfunctional high density lipoprotein. Curr Opin Cardiol 2008; 21:322-8. [PMID: 16755201 DOI: 10.1097/01.hco.0000231402.87232.aa] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Evidence indicates that high density lipoprotein (HDL) is cardioprotective and that several mechanisms are involved. One important pathway is a membrane-associated ATP-binding cassette transporter, ABCA1, that clears cholesterol from macrophage foam cells. Anti-inflammatory and antioxidant properties also might contribute to HDL's ability to inhibit atherosclerosis. RECENT FINDINGS Myeloperoxidase targets HDL for oxidation, raising the possibility that the enzyme provides a specific mechanism for generating dysfunctional HDL in humans. Myeloperoxidase-dependent oxidation of apolipoprotein A-I, the major protein in HDL, blocks HDL's ability to remove excess cholesterol from cells by the ABCA1 pathway. Analysis of mutated forms of apoA-I and oxidized apoA-I treated with methionine sulfoxide reductase implicate oxidation of specific tyrosine and methionine residues in impairing the ABCA1 transport activity of apoA-I. The crystal structure of lipid-free apoA-I suggests that such oxidative damage might disrupt negatively charged regions on the protein's surface or alter its remodeling, resulting in conformations that fail to interact with ABCA1. SUMMARY Oxidation of HDL by myeloperoxidase may represent a specific molecular mechanism for converting the cardioprotective lipoprotein into a dysfunctional form, raising the possibility that the enzyme represents a potential therapeutic target for preventing vascular disease in humans. Moreover, oxidized HDL might prove useful as a blood marker for clinically significant cardiovascular disease in humans.
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Affiliation(s)
- Baohai Shao
- Department of Medicine, University of Washington, Seattle, 98195, USA
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198
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Sivashanmugam A, Yang Y, Murray V, McCullough C, Chen B, Ren X, Li Q, Wang J. Chapter 15 Structural Basis of Human High‐density Lipoprotein Formation and Assembly at Sub nanometer Resolution. Methods Cell Biol 2008; 90:327-64. [DOI: 10.1016/s0091-679x(08)00815-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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199
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Chapter 11 Molecular Modeling of the Structural Properties and Formation of High-Density Lipoprotein Particles. CURRENT TOPICS IN MEMBRANES 2008. [DOI: 10.1016/s1063-5823(08)00011-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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200
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Aksimentiev A, Brunner R, Cohen J, Comer J, Cruz-Chu E, Hardy D, Rajan A, Shih A, Sigalov G, Yin Y, Schulten K. Computer modeling in biotechnology: a partner in development. Methods Mol Biol 2008; 474:181-234. [PMID: 19031067 DOI: 10.1007/978-1-59745-480-3_11] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Computational modeling can be a useful partner in biotechnology, in particular, in nanodevice engineering. Such modeling guides development through nanoscale views of biomolecules and devices not available through experimental imaging methods. We illustrate the role of computational modeling, mainly of molecular dynamics, through four case studies: development of silicon bionanodevices for single molecule electrical recording, development of carbon nano-tube-biomolecular systems as in vivo sensors, development of lipoprotein nanodiscs for assays of single membrane proteins, and engineering of oxygen tolerance into the enzyme hydrogenase for photosynthetic hydrogen gas production. The four case studies show how molecular dynamics approaches were adapted to the specific technical uses through (i) multi-scale extensions, (ii) fast quantum chemical force field evaluation, (iii) coarse graining, and (iv) novel sampling methods. The adapted molecular dynamics simulations provided key information on device behavior and revealed development opportunities, arguing that the "computational microscope" is an indispensable nanoengineering tool.
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Affiliation(s)
- Aleksei Aksimentiev
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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