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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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2
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Segrest JP, Jones MK, Catte A, Manchekar M, Datta G, Zhang L, Zhang R, Li L, Patterson JC, Palgunachari MN, Oram JF, Ren G. Surface Density-Induced Pleating of a Lipid Monolayer Drives Nascent High-Density Lipoprotein Assembly. Structure 2015; 23:1214-26. [PMID: 26095027 PMCID: PMC4496276 DOI: 10.1016/j.str.2015.05.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 04/22/2015] [Accepted: 05/05/2015] [Indexed: 11/28/2022]
Abstract
Biogenesis of high-density lipoproteins (HDL) is coupled to the transmembrane protein, ATP-binding cassette transporter A1 (ABCA1), which transports phospholipid (PL) from the inner to the outer membrane monolayer. Using a combination of computational and experimental approaches, we show that increased outer lipid monolayer surface density, driven by excess PL or membrane insertion of amphipathic helices, results in pleating of the outer monolayer to form membrane-attached discoidal bilayers. Apolipoprotein (apo)A-I accelerates and stabilizes the pleats. In the absence of apoA-I, pleats collapse to form vesicles. These results mimic cells overexpressing ABCA1 that, in the absence of apoA-I, form and release vesicles. We conclude that the basic driving force for nascent discoidal HDL assembly is a PL pump-induced surface density increase that produces lipid monolayer pleating. We then argue that ABCA1 forms an extracellular reservoir containing an isolated pressurized lipid monolayer decoupled from the transbilayer density buffering of cholesterol.
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Affiliation(s)
- Jere P Segrest
- Department of Medicine and Atherosclerosis Research Unit, University of Alabama at Birmingham, Birmingham, AL 35294-0012, USA; Center for Computational and Structural Dynamics, 630 BDB, UAB, Birmingham, AL 35294, USA.
| | - Martin K Jones
- Department of Medicine and Atherosclerosis Research Unit, University of Alabama at Birmingham, Birmingham, AL 35294-0012, USA; Center for Computational and Structural Dynamics, 630 BDB, UAB, Birmingham, AL 35294, USA
| | - Andrea Catte
- Department of Medicine and Atherosclerosis Research Unit, University of Alabama at Birmingham, Birmingham, AL 35294-0012, USA; Center for Computational and Structural Dynamics, 630 BDB, UAB, Birmingham, AL 35294, USA
| | - Medha Manchekar
- Department of Medicine and Atherosclerosis Research Unit, University of Alabama at Birmingham, Birmingham, AL 35294-0012, USA
| | - Geeta Datta
- Department of Medicine and Atherosclerosis Research Unit, University of Alabama at Birmingham, Birmingham, AL 35294-0012, USA
| | - Lei Zhang
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Robin Zhang
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ling Li
- Department of Medicine and Atherosclerosis Research Unit, University of Alabama at Birmingham, Birmingham, AL 35294-0012, USA
| | - James C Patterson
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL 35294-0012, USA
| | - Mayakonda N Palgunachari
- Department of Medicine and Atherosclerosis Research Unit, University of Alabama at Birmingham, Birmingham, AL 35294-0012, USA
| | - Jack F Oram
- Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Gang Ren
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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Studies of synthetic peptide analogs of the amphipathic helix. Effect of charge distribution, hydrophobicity, and secondary structure on lipid association and lecithin:cholesterol acyltransferase activation. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)48092-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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9
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Segrest JP, Chung BH, Brouillette CG, Kanellis P, McGahan R. Studies of synthetic peptide analogs of the amphipathic helix. Competitive displacement of exchangeable apolipoproteins from native lipoproteins. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(18)32921-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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10
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Dhawan S, Nityanand S, Kapoor NK, Singh S. Conformational transitions in serum high density apoproteins of hypercholesterolemic monkeys. Atherosclerosis 1982; 41:81-6. [PMID: 7073796 DOI: 10.1016/0021-9150(82)90072-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Conformational transitions in serum high density apolipoproteins of normal and hypercholesterolemic monkeys have been studied by circular dichroism. This study has revealed that under hypercholesterolemic conditions the secondary structure of apolipoproteins suffers permanent changes which could be observed even after a lengthy procedure of isolation, purification and delipidation of high density lipoprotein.
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Hauser H, Kostner GM. Structural organization of free and esterified cholesterol in human high density lipoproteins. A 100.6 MHz 13C NMR study. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 573:375-81. [PMID: 221035 DOI: 10.1016/0005-2760(79)90070-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The structural organization of free and esterified cholesterol in human high density lipoproteins has been studied by high-field 1H and 13C NMR. The measurements are consistent with free cholesterol being present in at least two different environments. Part of the free cholesterol is oriented in the outer surface layer of the high density lipoprotein particle in contact with phospholipid or apoprotein, or both. The rest is probably present in the liquid, hydrophobic core of the HDL particle.
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15
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Abstract
The complexity of the structure of plasma high density lipoproteins (HDL) has invited numerous approaches which have been directed at the study of the intact particles, their apolipoproteins and reassembled complexes. Parameters such as flotation and sedimentation coefficients, size and molecular weight have been determined and in addition, through scattering techniques, an understanding has been obtained on the long range organization between core (cholesteryl esters and triglycerides) and surface components (unesterified cholesterol, phospholipids and apoproteins). In the case of the apolipoproteins, the knowledge of their primary structure has facilitated the study of their physicochemical properties in solution and at the air-water interface and has also permitted realistic predictions of the two dimensional organization, not only of their alpha-helical segments but also of the beta-pleated sheets, random coil and beta-turns, all of which have amphipathic properties. When all of the information from the physical and chemical studies is put together, the various HDL can be described as spherical structures having a liquid core of radius, r - 20.2 A, surrounded by a monolayer of cholesterol and phospholipids with closely packed hydrophobic ends on the surface of the core. The organization of the apoproteins at the lipoprotein interface is comparatively less understood. However, reasonable predictions can be made on secondary structure considerations and on their behavior at the air-water interface. The emerging overall structural information can be translated into a space-filling model that not only provides a useful representation of HDL, but, more importantly, a basis for planning future studies on the elucidation of the structure of these particles on a molecular level.
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