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Luo G, Yang Q, Yao B, Tian Y, Hou R, Shao A, Li M, Feng Z, Wang W. Slp-coated liposomes for drug delivery and biomedical applications: potential and challenges. Int J Nanomedicine 2019; 14:1359-1383. [PMID: 30863066 PMCID: PMC6388732 DOI: 10.2147/ijn.s189935] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Slp forms a crystalline array of proteins on the outermost envelope of bacteria and archaea with a molecular weight of 40-200 kDa. Slp can self-assemble on the surface of liposomes in a proper environment via electrostatic interactions, which could be employed to functionalize liposomes by forming Slp-coated liposomes for various applications. Among the molecular characteristics, the stability, adhesion, and immobilization of biomacromolecules are regarded as the most meaningful. Compared to plain liposomes, Slp-coated liposomes show excellent physicochemical and biological stabilities. Recently, Slp-coated liposomes were shown to specifically adhere to the gastrointestinal tract, which was attributed to the "ligand-receptor interaction" effect. Furthermore, Slp as a "bridge" can immobilize functional biomacromol-ecules on the surface of liposomes via protein fusion technology or intermolecular forces, endowing liposomes with beneficial functions. In view of these favorable features, Slp-coated liposomes are highly likely to be an ideal platform for drug delivery and biomedical uses. This review aims to provide a general framework for the structure and characteristics of Slp and the interactions between Slp and liposomes, to highlight the unique properties and drug delivery as well as the biomedical applications of the Slp-coated liposomes, and to discuss the ongoing challenges and perspectives.
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Affiliation(s)
- Gan Luo
- Department of Pharmaceutics, College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, Zhejiang, China,
- Department of Anesthesiology and Intensive Care, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Qingliang Yang
- Department of Pharmaceutics, College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, Zhejiang, China,
| | - Bingpeng Yao
- Department of Pharmaceutics, College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, Zhejiang, China,
- Department of Green Pharmaceutics, Jianxing Honors College, Zhejiang University of Technology, Hangzhou, Zhejiang, China
| | - Yangfan Tian
- Department of Pediatric Surgery, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Ruixia Hou
- Department of Pharmaceutics, College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, Zhejiang, China,
| | - Anna Shao
- Department of Pharmaceutics, College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, Zhejiang, China,
| | - Mengting Li
- Department of Pharmaceutics, College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, Zhejiang, China,
| | - Zilin Feng
- Department of Pharmaceutics, College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, Zhejiang, China,
| | - Wenxi Wang
- Department of Pharmaceutics, College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, Zhejiang, China,
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Physicochemical characterization and gastrointestinal adhesion of S-layer proteins-coating liposomes. Int J Pharm 2017; 529:227-237. [DOI: 10.1016/j.ijpharm.2017.07.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 07/01/2017] [Accepted: 07/02/2017] [Indexed: 12/20/2022]
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Komaromy AZ, Kulsing C, Boysen RI, Hearn MTW. Salts employed in hydrophobic interaction chromatography can change protein structure - insights from protein-ligand interaction thermodynamics, circular dichroism spectroscopy and small angle X-ray scattering. Biotechnol J 2015; 10:417-26. [DOI: 10.1002/biot.201400465] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 01/05/2015] [Accepted: 02/17/2015] [Indexed: 01/07/2023]
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Sleytr UB, Schuster B, Egelseer E, Pum D. S-layers: principles and applications. FEMS Microbiol Rev 2014; 38:823-64. [PMID: 24483139 PMCID: PMC4232325 DOI: 10.1111/1574-6976.12063] [Citation(s) in RCA: 232] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 01/10/2014] [Accepted: 01/13/2014] [Indexed: 01/12/2023] Open
Abstract
Monomolecular arrays of protein or glycoprotein subunits forming surface layers (S-layers) are one of the most commonly observed prokaryotic cell envelope components. S-layers are generally the most abundantly expressed proteins, have been observed in species of nearly every taxonomical group of walled bacteria, and represent an almost universal feature of archaeal envelopes. The isoporous lattices completely covering the cell surface provide organisms with various selection advantages including functioning as protective coats, molecular sieves and ion traps, as structures involved in surface recognition and cell adhesion, and as antifouling layers. S-layers are also identified to contribute to virulence when present as a structural component of pathogens. In Archaea, most of which possess S-layers as exclusive wall component, they are involved in determining cell shape and cell division. Studies on structure, chemistry, genetics, assembly, function, and evolutionary relationship of S-layers revealed considerable application potential in (nano)biotechnology, biomimetics, biomedicine, and synthetic biology.
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Affiliation(s)
- Uwe B. Sleytr
- Institute of BiophysicsDepartment of NanobiotechnologyUniversity of Natural Resources and Life SciencesViennaAustria
| | - Bernhard Schuster
- Institute of Synthetic BiologyDepartment of NanobiotechnologyUniversity of Natural Resources and Life SciencesViennaAustria
| | - Eva‐Maria Egelseer
- Institute of BiophysicsDepartment of NanobiotechnologyUniversity of Natural Resources and Life SciencesViennaAustria
| | - Dietmar Pum
- Institute of BiophysicsDepartment of NanobiotechnologyUniversity of Natural Resources and Life SciencesViennaAustria
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Kontro I, Wiedmer SK, Hynönen U, Penttilä PA, Palva A, Serimaa R. The structure of Lactobacillus brevis surface layer reassembled on liposomes differs from native structure as revealed by SAXS. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2099-104. [DOI: 10.1016/j.bbamem.2014.04.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 04/03/2014] [Accepted: 04/23/2014] [Indexed: 11/29/2022]
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Small-angle X-ray scattering for imaging of surface layers on intact bacteria in the native environment. J Bacteriol 2013; 195:2408-14. [PMID: 23504021 DOI: 10.1128/jb.02164-12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Crystalline cell surface layers (S-layers) represent a natural two-dimensional (2D) protein self-assembly system with nanometer-scale periodicity that decorate many prokaryotic cells. Here, we analyze the S-layer on intact bacterial cells of the Gram-positive organism Geobacillus stearothermophilus ATCC 12980 and the Gram-negative organism Aquaspirillum serpens MW5 by small-angle X-ray scattering (SAXS) and relate it to the structure obtained by transmission electron microscopy (TEM) after platinum/carbon shadowing. By measuring the scattering pattern of X rays obtained from a suspension of bacterial cells, integral information on structural elements such as the thickness and lattice parameters of the S-layers on intact, hydrated cells can be obtained nondestructively. In contrast, TEM of whole mounts is used to analyze the S-layer lattice type and parameters as well as the physical structure in a nonaqueous environment and local information on the structure is delivered. Application of SAXS to S-layer research on intact bacteria is a challenging task, as the scattering volume of the generally thin (3- to 30-nm) bacterial S-layers is low in comparison to the scattering volume of the bacterium itself. For enhancement of the scattering contrast of the S-layer in SAXS measurement, either silicification (treatment with tetraethyl orthosilicate) is used, or the difference between SAXS signals from an S-layer-deficient mutant and the corresponding S-layer-carrying bacterium is used for determination of the scattering signal. The good agreement of the SAXS and TEM data shows that S-layers on the bacterial cell surface are remarkably stable.
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Pum D, Toca-Herrera JL, Sleytr UB. S-layer protein self-assembly. Int J Mol Sci 2013; 14:2484-501. [PMID: 23354479 PMCID: PMC3587997 DOI: 10.3390/ijms14022484] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 01/14/2013] [Accepted: 01/16/2013] [Indexed: 11/16/2022] Open
Abstract
Crystalline S(urface)-layers are the most commonly observed cell surface structures in prokaryotic organisms (bacteria and archaea). S-layers are highly porous protein meshworks with unit cell sizes in the range of 3 to 30 nm, and thicknesses of ~10 nm. One of the key features of S-layer proteins is their intrinsic capability to form self-assembled mono- or double layers in solution, and at interfaces. Basic research on S-layer proteins laid foundation to make use of the unique self-assembly properties of native and, in particular, genetically functionalized S-layer protein lattices, in a broad range of applications in the life and non-life sciences. This contribution briefly summarizes the knowledge about structure, genetics, chemistry, morphogenesis, and function of S-layer proteins and pays particular attention to the self-assembly in solution, and at differently functionalized solid supports.
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Affiliation(s)
- Dietmar Pum
- Department of Nanobiotechnology, Institute for Biophysics, University of Natural Resources and Life Science, Vienna, Muthgasse 11, Vienna 1190, Austria; E-Mails: (J.L.T.-H); (U.B.S.)
| | - Jose Luis Toca-Herrera
- Department of Nanobiotechnology, Institute for Biophysics, University of Natural Resources and Life Science, Vienna, Muthgasse 11, Vienna 1190, Austria; E-Mails: (J.L.T.-H); (U.B.S.)
| | - Uwe B. Sleytr
- Department of Nanobiotechnology, Institute for Biophysics, University of Natural Resources and Life Science, Vienna, Muthgasse 11, Vienna 1190, Austria; E-Mails: (J.L.T.-H); (U.B.S.)
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Ilk N, Egelseer EM, Sleytr UB. S-layer fusion proteins--construction principles and applications. Curr Opin Biotechnol 2011; 22:824-31. [PMID: 21696943 PMCID: PMC3271365 DOI: 10.1016/j.copbio.2011.05.510] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 05/24/2011] [Accepted: 05/24/2011] [Indexed: 12/04/2022]
Abstract
Crystalline bacterial cell surface layers (S-layers) are the outermost cell envelope component of many bacteria and archaea. S-layers are monomolecular arrays composed of a single protein or glycoprotein species and represent the simplest biological membrane developed during evolution. The wealth of information available on the structure, chemistry, genetics and assembly of S-layers revealed a broad spectrum of applications in nanobiotechnology and biomimetics. By genetic engineering techniques, specific functional domains can be incorporated in S-layer proteins while maintaining the self-assembly capability. These techniques have led to new types of affinity structures, microcarriers, enzyme membranes, diagnostic devices, biosensors, vaccines, as well as targeting, delivery and encapsulation systems.
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Horejs C, Ristl R, Tscheliessnig R, Sleytr UB, Pum D. Single-molecule force spectroscopy reveals the individual mechanical unfolding pathways of a surface layer protein. J Biol Chem 2011; 286:27416-24. [PMID: 21690085 PMCID: PMC3149335 DOI: 10.1074/jbc.m111.251322] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 06/15/2011] [Indexed: 12/14/2022] Open
Abstract
Surface layers (S-layers) represent an almost universal feature of archaeal cell envelopes and are probably the most abundant bacterial cell proteins. S-layers are monomolecular crystalline structures of single protein or glycoprotein monomers that completely cover the cell surface during all stages of the cell growth cycle, thereby performing their intrinsic function under a constant intra- and intermolecular mechanical stress. In gram-positive bacteria, the individual S-layer proteins are anchored by a specific binding mechanism to polysaccharides (secondary cell wall polymers) that are linked to the underlying peptidoglycan layer. In this work, atomic force microscopy-based single-molecule force spectroscopy and a polyprotein approach are used to study the individual mechanical unfolding pathways of an S-layer protein. We uncover complex unfolding pathways involving the consecutive unfolding of structural intermediates, where a mechanical stability of 87 pN is revealed. Different initial extensibilities allow the hypothesis that S-layer proteins adapt highly stable, mechanically resilient conformations that are not extensible under the presence of a pulling force. Interestingly, a change of the unfolding pathway is observed when individual S-layer proteins interact with secondary cell wall polymers, which is a direct signature of a conformational change induced by the ligand. Moreover, the mechanical stability increases up to 110 pN. This work demonstrates that single-molecule force spectroscopy offers a powerful tool to detect subtle changes in the structure of an individual protein upon binding of a ligand and constitutes the first conformational study of surface layer proteins at the single-molecule level.
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Affiliation(s)
| | - Robin Ristl
- From the Department for Nanobiotechnology and
| | - Rupert Tscheliessnig
- the Austrian Centre of Industrial Biotechnology, c/o Institute for Biotechnology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | | | - Dietmar Pum
- From the Department for Nanobiotechnology and
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Horejs C, Mitra MK, Pum D, Sleytr UB, Muthukumar M. Monte Carlo study of the molecular mechanisms of surface-layer protein self-assembly. J Chem Phys 2011; 134:125103. [PMID: 21456703 DOI: 10.1063/1.3565457] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The molecular mechanisms guiding the self-assembly of proteins into functional or pathogenic large-scale structures can be only understood by studying the correlation between the structural details of the monomer and the eventual mesoscopic morphologies. Among the myriad structural details of protein monomers and their manifestations in the self-assembled morphologies, we seek to identify the most crucial set of structural features necessary for the spontaneous selection of desired morphologies. Using a combination of the structural information and a Monte Carlo method with a coarse-grained model, we have studied the functional protein self-assembly into S(surface)-layers, which constitute the crystallized outer most cell envelope of a great variety of bacterial cells. We discover that only few and mainly hydrophobic amino acids, located on the surface of the monomer, are responsible for the formation of a highly ordered anisotropic protein lattice. The coarse-grained model presented here reproduces accurately many experimentally observed features including the pore formation, chemical description of the pore structure, location of specific amino acid residues at the protein-protein interfaces, and surface accessibility of specific amino acid residues. In addition to elucidating the molecular mechanisms and explaining experimental findings in the S-layer assembly, the present work offers a tool, which is chemical enough to capture details of primary sequences and coarse-grained enough to explore morphological structures with thousands of protein monomers, to promulgate design rules for spontaneous formation of specific protein assemblies.
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Affiliation(s)
- Christine Horejs
- Department for Nanobiotechnology, University of Natural Resources and Applied Life Sciences, 1190 Vienna, Austria
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Horejs C, Gollner H, Pum D, Sleytr UB, Peterlik H, Jungbauer A, Tscheliessnig R. Atomistic structure of monomolecular surface layer self-assemblies: toward functionalized nanostructures. ACS NANO 2011; 5:2288-2297. [PMID: 21375257 DOI: 10.1021/nn1035729] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The concept of self-assembly is one of the most promising strategies for the creation of defined nanostructures and therefore became an essential part of nanotechnology for the controlled bottom-up design of nanoscale structures. Surface layers (S-layers), which represent the cell envelope of a great variety of prokaryotic cells, show outstanding self-assembly features in vitro and have been successfully used as the basic matrix for molecular construction kits. Here we present the three-dimensional structure of an S-layer lattice based on tetrameric unit cells, which will help to facilitate the directed binding of various molecules on the S-layer lattice, thereby creating functional nanoarrays for applications in nanobiotechnology. Our work demonstrates the successful combination of computer simulations, electron microscopy (TEM), and small-angle X-ray scattering (SAXS) as a tool for the investigation of the structure of self-assembling or aggregating proteins, which cannot be determined by X-ray crystallography. To the best of our knowledge, this is the first structural model at an amino acid level of an S-layer unit cell that exhibits p4 lattice symmetry.
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Affiliation(s)
- Christine Horejs
- Department for Nanobiotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
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Sleytr UB, Schuster B, Egelseer EM, Pum D, Horejs CM, Tscheliessnig R, Ilk N. Nanobiotechnology with S-layer proteins as building blocks. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 103:277-352. [PMID: 21999999 DOI: 10.1016/b978-0-12-415906-8.00003-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
One of the key challenges in nanobiotechnology is the utilization of self- assembly systems, wherein molecules spontaneously associate into reproducible aggregates and supramolecular structures. In this contribution, we describe the basic principles of crystalline bacterial surface layers (S-layers) and their use as patterning elements. The broad application potential of S-layers in nanobiotechnology is based on the specific intrinsic features of the monomolecular arrays composed of identical protein or glycoprotein subunits. Most important, physicochemical properties and functional groups on the protein lattice are arranged in well-defined positions and orientations. Many applications of S-layers depend on the capability of isolated subunits to recrystallize into monomolecular arrays in suspension or on suitable surfaces (e.g., polymers, metals, silicon wafers) or interfaces (e.g., lipid films, liposomes, emulsomes). S-layers also represent a unique structural basis and patterning element for generating more complex supramolecular structures involving all major classes of biological molecules (e.g., proteins, lipids, glycans, nucleic acids, or combinations of these). Thus, S-layers fulfill key requirements as building blocks for the production of new supramolecular materials and nanoscale devices as required in molecular nanotechnology, nanobiotechnology, biomimetics, and synthetic biology.
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Affiliation(s)
- Uwe B Sleytr
- Department of NanoBiotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
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The Structure of Bacterial S-Layer Proteins. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 103:73-130. [DOI: 10.1016/b978-0-12-415906-8.00004-2] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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