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Schuster B, Sleytr UB. S-Layer Ultrafiltration Membranes. MEMBRANES 2021; 11:275. [PMID: 33918014 PMCID: PMC8068369 DOI: 10.3390/membranes11040275] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 03/30/2021] [Accepted: 04/03/2021] [Indexed: 11/29/2022]
Abstract
Monomolecular arrays of protein subunits forming surface layers (S-layers) are the most common outermost cell envelope components of prokaryotic organisms (bacteria and archaea). Since S-layers are periodic structures, they exhibit identical physicochemical properties for each constituent molecular unit down to the sub-nanometer level. Pores passing through S-layers show identical size and morphology and are in the range of ultrafiltration membranes. The functional groups on the surface and in the pores of the S-layer protein lattice are accessible for chemical modifications and for binding functional molecules in very precise fashion. S-layer ultrafiltration membranes (SUMs) can be produced by depositing S-layer fragments as a coherent (multi)layer on microfiltration membranes. After inter- and intramolecular crosslinking of the composite structure, the chemical and thermal resistance of these membranes was shown to be comparable to polyamide membranes. Chemical modification and/or specific binding of differently sized molecules allow the tuning of the surface properties and molecular sieving characteristics of SUMs. SUMs can be utilized as matrices for the controlled immobilization of functional biomolecules (e.g., ligands, enzymes, antibodies, and antigens) as required for many applications (e.g., biosensors, diagnostics, enzyme- and affinity-membranes). Finally, SUM represent unique supporting structures for stabilizing functional lipid membranes at meso- and macroscopic scale.
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Affiliation(s)
- Bernhard Schuster
- Institute for Synthetic Bioarchitectures, Department of NanoBiotechnology, BOKU—University of Natural Resources and Life Sciences, Vienna, Muthgasse 11, 1190 Vienna, Austria
| | - Uwe B. Sleytr
- Institute for Synthetic Bioarchitectures, Department of NanoBiotechnology, BOKU—University of Natural Resources and Life Sciences, Vienna, Muthgasse 11, 1190 Vienna, Austria
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Schuster B. S-Layer Protein-Based Biosensors. BIOSENSORS 2018; 8:E40. [PMID: 29641511 PMCID: PMC6023001 DOI: 10.3390/bios8020040] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 04/05/2018] [Accepted: 04/09/2018] [Indexed: 01/14/2023]
Abstract
The present paper highlights the application of bacterial surface (S-) layer proteins as versatile components for the fabrication of biosensors. One technologically relevant feature of S-layer proteins is their ability to self-assemble on many surfaces and interfaces to form a crystalline two-dimensional (2D) protein lattice. The S-layer lattice on the surface of a biosensor becomes part of the interface architecture linking the bioreceptor to the transducer interface, which may cause signal amplification. The S-layer lattice as ultrathin, highly porous structure with functional groups in a well-defined special distribution and orientation and an overall anti-fouling characteristics can significantly raise the limit in terms of variety and the ease of bioreceptor immobilization, compactness of bioreceptor molecule arrangement, sensitivity, specificity, and detection limit for many types of biosensors. The present paper discusses and summarizes examples for the successful implementation of S-layer lattices on biosensor surfaces in order to give a comprehensive overview on the application potential of these bioinspired S-layer protein-based biosensors.
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Affiliation(s)
- Bernhard Schuster
- Institute for Synthetic Bioarchitectures, Department of NanoBiotechnology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 11, 1190 Vienna, Austria.
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Poulos S, Agah S, Jallah N, Faham S. Symmetry based assembly of a 2 dimensional protein lattice. PLoS One 2017; 12:e0174485. [PMID: 28419162 PMCID: PMC5395157 DOI: 10.1371/journal.pone.0174485] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/09/2017] [Indexed: 12/05/2022] Open
Abstract
The design of proteins that self-assemble into higher order architectures is of great interest due to their potential application in nanotechnology. Specifically, the self-assembly of proteins into ordered lattices is of special interest to the field of structural biology. Here we designed a 2 dimensional (2D) protein lattice using a fusion of a tandem repeat of three TelSAM domains (TTT) to the Ferric uptake regulator (FUR) domain. We determined the structure of the designed (TTT-FUR) fusion protein to 2.3 Å by X-ray crystallographic methods. In agreement with the design, a 2D lattice composed of TelSAM fibers interdigitated by the FUR domain was observed. As expected, the fusion of a tandem repeat of three TelSAM domains formed 21 screw axis, and the self-assembly of the ordered oligomer was under pH control. We demonstrated that the fusion of TTT to a domain having a 2-fold symmetry, such as the FUR domain, can produce an ordered 2D lattice. The TTT-FUR system combines features from the rotational symmetry matching approach with the oligomer driven crystallization method. This TTT-FUR fusion was amenable to X-ray crystallographic methods, and is a promising crystallization chaperone.
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Affiliation(s)
- Sandra Poulos
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia, United States
| | - Sayeh Agah
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia, United States
| | - Nikardi Jallah
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia, United States
| | - Salem Faham
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia, United States
- * E-mail:
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Ucisik MH, Sleytr UB, Schuster B. Emulsomes meet S-layer proteins: an emerging targeted drug delivery system. Curr Pharm Biotechnol 2015; 16:392-405. [PMID: 25697368 PMCID: PMC4460288 DOI: 10.2174/138920101604150218112656] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 09/17/2014] [Accepted: 12/12/2014] [Indexed: 11/22/2022]
Abstract
Here, the use of emulsomes as a drug delivery system is reviewed and compared with other similar lipidic nanoformulations. In particular, we look at surface modification of emulsomes using S-layer proteins, which are self-assembling proteins that cover the surface of many prokaryotic organisms. It has been shown that covering emulsomes with a crystalline S-layer lattice can protect cells from oxidative stress and membrane damage. In the future, the capability to recrystallize S-layer fusion proteins on lipidic nanoformulations may allow the presentation of binding functions or homing protein domains to achieve highly specific targeted delivery of drug-loaded emulsomes. Besides the discussion on several designs and advantages of composite emulsomes, the success of emulsomes for the delivery of drugs to fight against viral and fungal infections, dermal therapy, cancer, and autoimmunity is summarized. Further research might lead to smart, biocompatible emulsomes, which are able to protect and reduce the side effects caused by the drug, but at the same time are equipped with specific targeting molecules to find the desired site of action.
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Affiliation(s)
| | | | - Bernhard Schuster
- Department of Biomedical Engineering, School of Engineering and Natural Sciences, Istanbul Medipol University, Ekinciler Cad. No.19, 34810 Beykoz, Istanbul, Turkey.
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Ladenhauf EM, Pum D, Wastl DS, Toca-Herrera JL, Phan NVH, Lieberzeit PA, Sleytr UB. S-layer based biomolecular imprinting. RSC Adv 2015. [DOI: 10.1039/c5ra14971a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AFM image of an S-layer protein array used for making molecular imprints.
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Affiliation(s)
- Eva M. Ladenhauf
- University of Natural Resources and Life Sciences, Vienna
- Department of Nanobiotechnology
- Institute of Biophysics
- A-1190 Vienna
- Austria
| | - Dietmar Pum
- University of Natural Resources and Life Sciences, Vienna
- Department of Nanobiotechnology
- Institute of Biophysics
- A-1190 Vienna
- Austria
| | - Daniel S. Wastl
- University of Natural Resources and Life Sciences, Vienna
- Department of Nanobiotechnology
- Institute of Biophysics
- A-1190 Vienna
- Austria
| | - Jose Luis Toca-Herrera
- University of Natural Resources and Life Sciences, Vienna
- Department of Nanobiotechnology
- Institute of Biophysics
- A-1190 Vienna
- Austria
| | - Nam V. H. Phan
- University of Vienna
- Department of Analytical Chemistry
- A-1090 Vienna
- Austria
| | | | - Uwe B. Sleytr
- University of Natural Resources and Life Sciences, Vienna
- Department of Nanobiotechnology
- Institute of Biophysics
- A-1190 Vienna
- Austria
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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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Identification and characterization of mimotopes of classical swine fever virus E2 glycoprotein using specific anti-E2 monoclonal antibodies. Virus Res 2013; 175:12-9. [DOI: 10.1016/j.virusres.2013.03.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 03/22/2013] [Accepted: 03/26/2013] [Indexed: 11/18/2022]
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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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Production, secretion, and cell surface display of recombinant Sporosarcina ureae S-layer fusion proteins in Bacillus megaterium. Appl Environ Microbiol 2011; 78:560-7. [PMID: 22101038 DOI: 10.1128/aem.06127-11] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Monomolecular crystalline bacterial cell surface layers (S-layers) have broad application potential in nanobiotechnology due to their ability to generate functional supramolecular structures. Here, we report that Bacillus megaterium is an excellent host organism for the heterologous expression and efficient secretion of hemagglutinin (HA) epitope-tagged versions of the S-layer protein SslA from Sporosarcina ureae ATCC 13881. Three chimeric proteins were constructed, comprising the precursor, C-terminally truncated, and N- and C-terminally truncated forms of the S-layer SslA protein tagged with the human influenza hemagglutinin epitope. For secretion of fusion proteins, the open reading frames were cloned into the Escherichia coli-Bacillus megaterium shuttle vector pHIS1525. After transformation of the respective plasmids into Bacillus megaterium protoplasts, the recombinant genes were successfully expressed and the proteins were secreted into the growth medium. The isolated S-layer proteins are able to assemble in vitro into highly ordered, crystalline, sheetlike structures with the fused HA tag accessible to antibody. We further show by fluorescent labeling that the secreted S-layer fusion proteins are also clustered on the cell envelope of Bacillus megaterium, indicating that the cell surface can serve in vivo as a nucleation point for crystallization. Thus, this system can be used as a display system that allows the dense and periodic presentation of S-layer proteins or the fused tags.
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Chen Y, Luo W, Song H, Yin B, Tang J, Chen Y, Ng MH, Yeo AET, Zhang J, Xia N. Mimotope ELISA for detection of broad spectrum antibody against avian H5N1 influenza virus. PLoS One 2011; 6:e24144. [PMID: 21912666 PMCID: PMC3166295 DOI: 10.1371/journal.pone.0024144] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 08/01/2011] [Indexed: 11/18/2022] Open
Abstract
Background We have raised a panel of broad spectrum neutralizing monoclonal antibodies against the highly pathogenic H5N1 avian influenza virus, which neutralize the infectivity of, and afford protection against infection by, most of the major genetic groups of the virus evolved since 1997. Peptide mimics reactive with one of these broad spectrum H5N1 neutralizing antibodies, 8H5, were identified from random phage display libraries. Method The amino acid residues of the most reactive 12mer peptide, p125 (DTPLTTAALRLV), were randomly substituted to improve its mimicry of the natural 8H5 epitope. Result 133 reactive peptides with unique amino acid sequences were identified from 5 sub-libraries of p125. Four residues (2,4,5.9) of the parental peptide were preserved among all the derived peptides and probably essential for 8H5 binding. These are interspersed among four other residues (1,3,8,10), which exhibit restricted substitution and probably could contribute to binding, and another four (6,7,11,12) which could be randomly substituted and probably are not essential for binding. One peptide, V-1b, derived by substituting 5 of the latter residues is the most reactive and has a binding constant of 3.16×10−9 M, which is 38 fold higher than the affinity of the parental p125. Immunoassay produced with this peptide is specifically reactive with 8H5 but not also the other related broad spectrum H5N1 avian influenza virus neutralizing antibodies. Serum samples from 29 chickens infected with H5N1 avian influenza virus gave a positive result by this assay and those from 12 uninfected animals gave a negative test result. Conclusion The immunoassay produced with the 12 mer peptide,V1-b, is specific for the natural 8H5 epitope and can be used for detection of antibody against the broad spectrum neutralization site of H5N1 avian influenza virus.
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Affiliation(s)
- Yingwei Chen
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, The Key Laboratory of Education Minister for Cell Biology and Tumor Cell Engineering of Xiamen University, School of Life Sciences, Xiamen University, Xiamen, China
| | - Wenxin Luo
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, The Key Laboratory of Education Minister for Cell Biology and Tumor Cell Engineering of Xiamen University, School of Life Sciences, Xiamen University, Xiamen, China
- * E-mail: (NX); (WL)
| | - Huijuan Song
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, The Key Laboratory of Education Minister for Cell Biology and Tumor Cell Engineering of Xiamen University, School of Life Sciences, Xiamen University, Xiamen, China
| | - Boyuan Yin
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, The Key Laboratory of Education Minister for Cell Biology and Tumor Cell Engineering of Xiamen University, School of Life Sciences, Xiamen University, Xiamen, China
| | - Jixian Tang
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, The Key Laboratory of Education Minister for Cell Biology and Tumor Cell Engineering of Xiamen University, School of Life Sciences, Xiamen University, Xiamen, China
| | - Yixin Chen
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, The Key Laboratory of Education Minister for Cell Biology and Tumor Cell Engineering of Xiamen University, School of Life Sciences, Xiamen University, Xiamen, China
| | - Mun Hon Ng
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, The Key Laboratory of Education Minister for Cell Biology and Tumor Cell Engineering of Xiamen University, School of Life Sciences, Xiamen University, Xiamen, China
| | - Anthony E. T. Yeo
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, The Key Laboratory of Education Minister for Cell Biology and Tumor Cell Engineering of Xiamen University, School of Life Sciences, Xiamen University, Xiamen, China
| | - Jun Zhang
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, The Key Laboratory of Education Minister for Cell Biology and Tumor Cell Engineering of Xiamen University, School of Life Sciences, Xiamen University, Xiamen, China
| | - Ningshao Xia
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, The Key Laboratory of Education Minister for Cell Biology and Tumor Cell Engineering of Xiamen University, School of Life Sciences, Xiamen University, Xiamen, China
- * E-mail: (NX); (WL)
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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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12
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Casey JL, Sanalla AM, Tamvakis D, Thalmann C, Carroll EL, Parisi K, Coley AM, Stewart DJ, Vaughan JA, Michalski WP, Luke R, Foley M. Peptides specific for Mycobacterium avium subspecies paratuberculosis infection: diagnostic potential. Protein Eng Des Sel 2011; 24:589-96. [PMID: 21669956 DOI: 10.1093/protein/gzr026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mycobacterium avium subspecies paratuberculosis (Map) is the causative agent of Johne's disease (JD). Current serological diagnostic tests for JD are limited by their sensitivity when used in sub-clinical stages of the disease. Our objective was to identify peptides that mimic diagnostically important Map epitopes that might be incorporated into a new-generation JD diagnostic. Four peptides were isolated from a phage-displayed random peptide library by screening on antibodies derived from Map-infected goats. The peptides were recognised by antibodies from Map-infected goats but not by antibodies from uninfected goats. The peptides elicited immune responses in rabbits, which reacted strongly with bona fide Map antigens proving the peptides were true epitope mimics. To assess the diagnostic value a panel of goat sera was screened for reactivity's with peptides. The peptides were recognised by antibodies from a proportion of goats infected with Map compared with control animals with a diagnostic specificity of 100% and the sensitivity ranged from 50 to 75%. Combinations of any two peptides improved sensitivity 62.5-87.5% and 100% sensitivity was achieved with three of the four peptides in combination. These data suggest peptides representing diagnostically important Map epitopes could be incorporated into a sensitive diagnostic test.
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Affiliation(s)
- J L Casey
- La Trobe University, AdAlta Pty Ltd, 2 Research Drive, VIC 3083, Australia.
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Horejs C, Pum D, Sleytr UB, Peterlik H, Jungbauer A, Tscheliessnig R. Surface layer protein characterization by small angle x-ray scattering and a fractal mean force concept: from protein structure to nanodisk assemblies. J Chem Phys 2011; 133:175102. [PMID: 21054069 DOI: 10.1063/1.3489682] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Surface layers (S-layers) are the most commonly observed cell surface structure of prokaryotic organisms. They are made up of proteins that spontaneously self-assemble into functional crystalline lattices in solution, on various solid surfaces, and interfaces. While classical experimental techniques failed to recover a complete structural model of an unmodified S-layer protein, small angle x-ray scattering (SAXS) provides an opportunity to study the structure of S-layer monomers in solution and of self-assembled two-dimensional sheets. For the protein under investigation we recently suggested an atomistic structural model by the use of molecular dynamics simulations. This structural model is now refined on the basis of SAXS data together with a fractal assembly approach. Here we show that a nondiluted critical system of proteins, which crystallize into monomolecular structures, might be analyzed by SAXS if protein-protein interactions are taken into account by relating a fractal local density distribution to a fractal local mean potential, which has to fulfill the Poisson equation. The present work demonstrates an important step into the elucidation of the structure of S-layers and offers a tool to analyze the structure of self-assembling systems in solution by means of SAXS and computer simulations.
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Affiliation(s)
- Christine Horejs
- Department for Nanobiotechnology, University of Natural Resources and Applied Life Sciences, 1090 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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15
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Lopez AE, Moreno-Flores S, Pum D, Sleytr UB, Toca-Herrera JL. Surface dependence of protein nanocrystal formation. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2010; 6:396-403. [PMID: 19943246 DOI: 10.1002/smll.200901169] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The self-assembly kinetics and nanocrystal formation of the bacterial surface-layer-protein SbpA are studied with a combination of quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM). Silane coupling agents, aminopropyltriethoxysilane (APTS) and octadecyltrichlorosilane (OTS), are used to vary the protein-surface interaction in order to induce new recrystallization pathways. The results show that the final S-layer crystal lattice parameters (a = b = 14 nm, gamma = 90 degrees ), the layer thickness (15 nm), and the adsorbed mass density (1700 ng cm(-2)) are independent of the surface chemistry. Nevertheless, the adsorption rate is five times faster on APTS and OTS than on SiO(2,) strongly affecting protein nucleation and growth. As a consequence, protein crystalline domains of 0.02 microm(2) for APTS and 0.05 microm(2) for OTS are formed, while for silicon dioxide the protein domains have a typical size of about 32 microm(2). In addition, more-rigid crystalline protein layers are formed on hydrophobic substrates. In situ AFM experiments reveal three different kinetic steps: adsorption, self-assembly, and crystalline-domain reorganization. These steps are corroborated by frequency-dissipation curves. Finally, it is shown that protein adsorption is a diffusion-driven process. Experiments at different protein concentrations demonstrate that protein adsorption saturates at 0.05 mg mL(-1) on silane-coated substrates and at 0.07 mg mL(-1) on hydrophilic silicon dioxide.
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Antibody reactivity of conformational peptide mimics of a conserved H5N1 neutralization site in different fusion proteins. Arch Virol 2009; 155:19-26. [PMID: 19911251 DOI: 10.1007/s00705-009-0542-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Accepted: 10/07/2009] [Indexed: 10/20/2022]
Abstract
Several peptide mimics of a conserved H5N1 avian influenza virus neutralization site recognized by 8H5 mAb have been reported previously. In this study, the secondary and possibly higher structural orders of the peptide mimics 122 and 125 were investigated and found to be closely related to the specific binding with 8H5 mAb. These two peptide mimics were fused to three different carrier proteins, and the antibody binding activities were recovered in 4 of the 11 fusion proteins. HEV structural protein p239 and HBc were more suitable than the outer membrane protein T47 of the Treponema pallidum particle for the recovery of reactivity. The increase in the copy number of peptide mimics was important for the recovery of antibody-binding activity and the interaction between peptide and carrier protein may affect the spatial structure of both the peptide and the carrier protein. These results are likely to be of relevance for conformational peptide mimics in diagnostic tests, vaccine and inhibitors.
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Abstract
Integral membrane proteins are important biological macromolecules with structural features and functionalities that make them attractive targets for nanotechnology. I provide here a broad review of current activity in nanotechnology related to membrane proteins, including their application as nanoscale sensors, switches, components of optical devices and as templates for self-assembled arrays.
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Casey JL, Coley AM, Parisi K, Foley M. Peptide mimics selected from immune sera using phage display technology can replace native antigens in the diagnosis of Epstein-Barr virus infection. Protein Eng Des Sel 2008; 22:85-91. [PMID: 19073711 PMCID: PMC2660343 DOI: 10.1093/protein/gzn076] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
There is an expanding area of small molecule discovery, especially in the area of peptide mimetics. Peptide sequences can be used to substitute for the entire native antigen for use in diagnostic assays. Our approach is to select peptides that mimic epitopes of the natural immune response to Epstein–Barr virus (EBV) that may be recognised by antibodies typically produced after infection with EBV. We screened a random peptide library on sera from rabbits immunised with a crude preparation of EBV and serum antibodies from a patient with a high titer of EBV antibodies. We selected four peptides (Eb1–4) with the highest relative binding affinity with immune rabbit sera and a single peptide with high affinity to human serum antibodies. The peptides were coupled to the carrier molecule BSA and the recognition of the peptides by IgM antibodies in clinical samples after infection with EBV was measured. The sensitivities were Eb1 94%, Eb2, 3, 4 88%, H1 81% and all had 100% specificity. This study illustrates that the phage display approach to select epitope mimics can be applied to polyclonal antibodies and peptides that represent several diagnostically important epitopes can be selected simultaneously. This panel of EBV peptides representing a wide coverage of immunodominant epitopes could replace crude antigen preparations currently used for capture in commercial diagnostic tests for EBV.
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Affiliation(s)
- J L Casey
- AdAlta Pty Ltd, 15/2 Park Drive, Bundoora, VIC 3083, Australia
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