1
|
Liu J, Falke S, Drobot B, Oberthuer D, Kikhney A, Guenther T, Fahmy K, Svergun D, Betzel C, Raff J. Analysis of self-assembly of S-layer protein slp-B53 from Lysinibacillus sphaericus. Eur Biophys J 2016; 46:77-89. [PMID: 27270294 DOI: 10.1007/s00249-016-1139-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 04/29/2016] [Accepted: 05/12/2016] [Indexed: 10/21/2022]
Abstract
The formation of stable and functional surface layers (S-layers) via self-assembly of surface-layer proteins on the cell surface is a dynamic and complex process. S-layers facilitate a number of important biological functions, e.g., providing protection and mediating selective exchange of molecules and thereby functioning as molecular sieves. Furthermore, S-layers selectively bind several metal ions including uranium, palladium, gold, and europium, some of them with high affinity. Most current research on surface layers focuses on investigating crystalline arrays of protein subunits in Archaea and bacteria. In this work, several complementary analytical techniques and methods have been applied to examine structure-function relationships and dynamics for assembly of S-layer protein slp-B53 from Lysinibacillus sphaericus: (1) The secondary structure of the S-layer protein was analyzed by circular dichroism spectroscopy; (2) Small-angle X-ray scattering was applied to gain insights into the three-dimensional structure in solution; (3) The interaction with bivalent cations was followed by differential scanning calorimetry; (4) The dynamics and time-dependent assembly of S-layers were followed by applying dynamic light scattering; (5) The two-dimensional structure of the paracrystalline S-layer lattice was examined by atomic force microscopy. The data obtained provide essential structural insights into the mechanism of S-layer self-assembly, particularly with respect to binding of bivalent cations, i.e., Mg2+ and Ca2+. Furthermore, the results obtained highlight potential applications of S-layers in the fields of micromaterials and nanobiotechnology by providing engineered or individual symmetric thin protein layers, e.g., for protective, antimicrobial, or otherwise functionalized surfaces.
Collapse
Affiliation(s)
- Jun Liu
- Laboratory for Structural Biology of Infection and Inflammation, Institute of Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King Platz 6, 20146, Hamburg, Germany.,Bioengineering Faculty, Sichuan University of Science and Engineering, Huixing Rd., Xueyuan Street 180, Zigong, 643000, Sichuan, China
| | - Sven Falke
- Laboratory for Structural Biology of Infection and Inflammation, Institute of Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King Platz 6, 20146, Hamburg, Germany
| | - Bjoern Drobot
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328, Dresden, Germany
| | - Dominik Oberthuer
- Laboratory for Structural Biology of Infection and Inflammation, Institute of Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King Platz 6, 20146, Hamburg, Germany.,Center for Free-Electron Laser Science (CFEL), DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Alexey Kikhney
- EMBL Hamburg, European Molecular Biology Laboratory, Notkestr. 85, 22607, Hamburg, Germany
| | - Tobias Guenther
- Helmholtz Institute Freiberg for Resource Technology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328, Dresden, Germany
| | - Karim Fahmy
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328, Dresden, Germany
| | - Dmitri Svergun
- EMBL Hamburg, European Molecular Biology Laboratory, Notkestr. 85, 22607, Hamburg, Germany
| | - Christian Betzel
- Laboratory for Structural Biology of Infection and Inflammation, Institute of Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King Platz 6, 20146, Hamburg, Germany
| | - Johannes Raff
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328, Dresden, Germany. .,Helmholtz Institute Freiberg for Resource Technology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328, Dresden, Germany.
| |
Collapse
|
2
|
Zhang MC, Allen TW, Drobot B, McFarlane S, Meldrum A, DeCorby RG. Transparency and stability of Ag-based metal-dielectric multilayers. Appl Opt 2013; 52:7479-7485. [PMID: 24216646 DOI: 10.1364/ao.52.007479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 09/26/2013] [Indexed: 06/02/2023]
Abstract
We fabricated and tested periodic metal (Ag)-dielectric (SiO2 or TiO2) multilayers with transparency bands in the visible range. For samples with Ag-TiO2 interfaces, the optical properties exhibited relatively poor predictability, likely due to oxidation of the Ag layers. Ag/SiO2-based multilayers were found to be more predictable and stable, but the relatively low refractive index of SiO2 limits their inherent transparency and pass-band bandwidth. We show that termination of the multilayer with a single high-index layer reduces the admittance mismatch with the ambient media, and thus improves the properties of the transparency band.
Collapse
|
3
|
Epp E, Ponnampalam N, Newman W, Drobot B, McMullin JN, Meldrum AF, DeCorby RG. Hollow Bragg waveguides fabricated by controlled buckling of Si/SiO2 multilayers. Opt Express 2010; 18:24917-24925. [PMID: 21164836 DOI: 10.1364/oe.18.024917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We describe integrated air-core waveguides with Bragg reflector claddings, fabricated by controlled delamination and buckling of sputtered Si/SiO2 multilayers. Thin film deposition parameters were tailored to produce a desired amount of compressive stress, and a patterned, embedded fluorocarbon layer was used to define regions of reduced adhesion. Self-assembled air channels formed either spontaneously or upon heating-induced decomposition of the patterned film. Preliminary optical experiments confirmed that light is confined to the air channels by a photonic band-gap guidance mechanism, with loss ~5 dB/cm in the 1550 nm wavelength region. The waveguides employ standard silicon processes and have potential applications in MEMS and lab-on-chip systems.
Collapse
Affiliation(s)
- E Epp
- ECE Department, University of Alberta, 2nd Floor, 9107-116 St. NW, Edmonton, AB, T6G 2V4, Canada
| | | | | | | | | | | | | |
Collapse
|