Site-specific electronic structure of bacterial surface protein layers

Vyalikh, D. V.; Kummer, K.; Kade, Andreas; Blüher, Anja; Katzschner, Beate; Mertig, Michael; Молодцов, С. Л.

doi:10.1007/s00339-008-4913-4

Cited by 5 publications

(2 citation statements)

References 22 publications

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“…This indicates that the highest occupied states contain a major contribution from Cu 3d-derived states. On the other hand, it is well-known that systems containing aromatic carbons show a significant C 2p contribution to the VB structure at BE ≈ 4 eV, too. − However, the geometry of the systems under study does not allow hybridization of Cu 3d-derived states and the C 2p states in the aromatic structures because they are spatially well-separated and overlap weakly or not at all. Essential contributions from Au 5d states to the HOMO are unlikely because, as we have seen, they possess higher BEs.…”

Section: Experimental Results and Discussionmentioning

confidence: 99%

Self-Assembled Supramolecular Complexes with “Rods-in-Belt” Architecture in the Light of Soft X-rays

et al. 2013

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One of the most important properties of the recently discovered "rods-in-belt" supramolecular complexes containing Au−Cu or Au−Ag cluster cores is the possibility of tuning their electronic and photophysical properties through modification of the ligand environment. This opens great perspectives for their applications in lightemitting devices and bioimaging. The high structural ordering and selfassembly properties of these unique objects may be used to design artificial nanostructures with complex topologies that could become ideal building blocks for next-generation electronics. Here we present a detailed experimental study of the electronic structure of "rods-in-belt" supramolecular complexes. Applying X-ray photoemission and absorption spectroscopy, we systematically unraveled the structure of their occupied and unoccupied electronic states near the Fermi level. The major contribution to the highest occupied molecular orbitals is made by the triple-bonded carbons hosted in the dialkynylgold "rods" and the copper (silver) atoms from the central cluster core of the heterometallic Au−Cu (Au−Ag) molecules. The lowest unoccupied molecular orbitals are located on the carbon skeleton of the complexes, including −CC− and −CC− aromatic orbitals. The onset of the valence band in the Au−Ag systems is ∼0.3 eV lower than that in the Au−Cu complexes, implying a slightly larger energy gap for the silver-based molecules. With increasing size, the complexes become more and more sensitive to X-ray damage.

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Section: Experimental Results and Discussionmentioning

confidence: 99%

Self-Assembled Supramolecular Complexes with “Rods-in-Belt” Architecture in the Light of Soft X-rays

et al. 2013

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“…An SL protein, which has been intensively studied regarding its physiological behavior , recrystallization , electronic structure , durability for X‐ray radiation , and interaction with physically deposited metals , is derived from Lysinibacillus sphaericus NCTC 9602 (former known as Bacillus sphaericus NCTC 9602). The 1–1.5 μm wide and 4–6 μm long, spore‐forming cells of this Gram‐positive bacterium are able to selectively bind high amounts of U, Pb, Cd, Cu, and Al .…”

Section: Introductionmentioning

confidence: 99%

Extraction and long‐term storage of S‐layer proteins and flagella from Lysinibacillus sphaericus NCTC 9602: Building blocks for nanotechnology

Blüher

Jäckel

Clemens

et al. 2015

Engineering in Life Sciences

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Self‐assembling surface layer (SL) proteins of bacteria have been widely studied, in particular their use as molecularly defined, 2D coatings of technical surfaces. An important prerequisite is the availability of a sufficient amount of protein. However, a detailed and optimized protocol for the complete SL extraction is so far not available. Here, we describe the complete purification and reassembly procedure of an SL protein of Lysinibacillus sphaericus NCTC 9602, starting from the cultivation of cells, the preparation and purification of SL proteins up to the long‐term storage and in vitro self‐assembly of the proteins. All crucial steps of the procedure are assessed by different microscopic techniques, such as light microscopy, atomic force microscopy, and scanning electron microscopy as well as by SDS‐PAGE as a biochemical method. We demonstrate that storage of the protein in the presence of sodium azide or upon lyophilization allows the preservation of the self‐assembly properties for at least 9 years. Additionally, we describe a method allowing the extraction of intact flagella with lengths in the range up to 4 μm. Flagella may have applications in bio‐nanotechnology, for example as templates for metallic nanowires.

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