Structural Reorganization of Phospholipid Headgroups upon Recrystallization of an S-Layer Lattice

Weygand, M.; Kjær, Kristian; Howes, P.B.; Wetzer, Barbara; Pum, Dietmar; Sleytr, Uwe B.; Lösche, Mathias

doi:10.1021/jp0146418

Cited by 35 publications

(47 citation statements)

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“…Since the protein content of outer membranes can be very high (Chalcroft et al, 1987;Kocsis et al, 1993) non-specific but also specific interactions of outer membrane and S-layer proteins are possible or even likely (Engelhardt and Peters, 1998). In contrast to small peptides, which intercalate into the head group regime of lipid membranes but do not influence the phase behavior of the lipids significantly (Weygand et al, 2002), large membrane proteins are in close contact with lipids that form a monomolecular annulus or even larger domains of immobilised lipids around the protein molecules (Jensen and Mouritsen, 2004). If outer membrane proteins were specifically immobilised by the crystalline surface protein, significant effects on the physico-chemical properties of the outer membrane could be expected in addition to possible functional interactions of the membrane and surface proteins.…”

Section: S-layer-outer Membrane Associationsmentioning

confidence: 99%

Are S-layers exoskeletons? The basic function of protein surface layers revisited

Engelhardt

2007

Journal of Structural Biology

131

121

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Surface protein or glycoprotein layers (Slayers) are common structures of the prokaryotic cell envelope. They are either associated with the peptidoglycan or outer membrane of bacteria, and constitute the only cell wall component of many archaea. Despite their occurrence in most of the phylogenetic branches of microorganisms, the functional significance of S-layers is assumed to be specific for genera or groups of organisms in the same environment rather than common to all prokaryotes. Functional aspects have usually been investigated with isolated S-layer sheets or proteins, which disregards the interactions between S-layers and the underlying cell envelope components. This study discusses the synergistic effects in cell envelope assemblies, the hypothetical role of S-layers for cell shape formation, and the existence of a common function in view of new insights.

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Section: S-layer-outer Membrane Associationsmentioning

confidence: 99%

Are S-layers exoskeletons? The basic function of protein surface layers revisited

Engelhardt

2007

Journal of Structural Biology

131

121

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“…A handful of studies have examined detailed local changes in the ordered packing structure of lipids in gel phase upon protein adsorption by GIXD [11][12][13][14][15]. Several of these investigated the effect of electrostatic interactions on the extent of segmental insertion by varying the charge on the lipid head group for a given adsorbing protein or peptide [11,13,15].…”

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confidence: 99%

Rearrangement of Lipid Ordered Phases Upon Protein Adsorption Due to Multiple Site Binding

et al. 2006

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This study involves the interactions of proteins with Langmuir monolayers of a metal-chelating lipid, where adsorption is driven by a strong specific interaction between histidines on the proteins and divalent metal ions loaded into the lipid headgroups. A comparison of the structural rearrangement of the lipid film upon adsorption of myoglobin and a synthetic peptide, each of which have multiple histidines, with that upon the adsorption of lysozyme, which has only one histidine, suggests that the lipid rearrangement in the former case is due to the multiplicity of binding sites. The kinetics and manner of rearrangement change with the binding energy and film pressure.Knowledge of the dynamical processes involved when proteins associate with lipid membranes is important for understanding many biological processes such as cell signaling [1] and toxin assault on cells [2,3] as well as for the development of novel biomaterials. A deeper understanding of protein interactions with lipid membranes could aid in the development of new drugs, as well as biosensors and other synthetic architectures. Many biophysical aspects of this interaction have yet to be understood in full detail. For example, the effects of single versus multiple-site binding, the conditions leading to insertion of segments into the lipid membrane, and understanding when conformational changes of the protein occur are all important but unresolved issues. This Letter focuses on the effects on lipid monolayers of the binding of proteins through multiple versus single specific binding sites. For the present model system, we show that irreversible binding through multiple sites on the protein leads to alteration of lipid in-plane order, and that the kinetics and manner of rearrangement change with the binding energy and film pressure.Several lipid membrane platforms exist for biomimetic studies, including vesicles, supported lipid bilayers, and lipid monolayers at the air-water interface. Since lipid bilayer membranes in physiological conditions can expand and contract as they interact with proteins and other analytes, it is desirable to understand the interaction with proteins under controlled pressure (variable area per molecule). Langmuir monolayers offer a model system where the surface area and surface pressure are not only controlled but can be monitored to give additional insight into the protein-membrane interaction. In this study, the effect of protein adsorption on the phase behavior of lipid monolayers was examined using time-resolved grazing incidence x-ray diffraction (GIXD), x-ray reflection (XR), and neutron reflection (NR). GIXD yields information on the laterally ordered, diffracting portion of the lipid monolayer [4]. By monitoring the diffraction peak arising from the ordered packing of the lipid tails, the effect of protein binding on the structure and phase behavior of the lipid film can be examined. XR and NR provide information about the adsorbed amount as well as the thickness of the adsorbed protein layer [5]. XR also pro...

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“…This is more a technical limitation than a limitation due to the method. A way to overcome these technical restrictions would be the use of a much more brilliant X-ray beam from third-generation synchrotron radiation sources, which would reduce the measurement times significantly and concomitantly improve the signal quality (41)(42)(43).…”

Section: Discussionmentioning

confidence: 99%

Small-Angle X-Ray Scattering for Imaging of Surface Layers on Intact Bacteria in the Native Environment

et al. 2013

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Crystalline cell surface layers (S-layers) represent a natural two-dimensional (2D) protein self-assembly system with nanometerscale 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 smallangle 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. Surface layers (S-layers) are a distinct cell surface decoration comprised of regularly arrayed, two-dimensional (2D) protein or glycoprotein crystals present on many prokaryotic organisms from almost all known phylogenetic branches (1-4). S-layers form upon self-assembly and exhibit nanometer-scale periodicity with oblique (p1, p2), square (p4), or hexagonal (p3, p6) lattice symmetry and species-specific lattice constant values in the range of 10 to 25 nm. The S-layer self-assembly system holds great promise as a bottom-up approach for organizing matter at the nanometer scale as required in the field of nanobiotechnology (5).Because of their cell surface location, ultrastructural studies of S-layer lattices have been frequently performed by high-resolution transmission electron microscopic (TEM) methods such as ultrathin sectioning or heavy-metal shadow casting of freezeetched or freeze-dried whole cells (6) as well as image analysis (7) or cryo-sectioning of frozen-hydrated cells (8). These electron microscopic approaches, except the latter, suffer from the drawback of the requirement for water-free specimens, implying a requirement for specific sample treatment prior to analysis. The standard procedures of chemical fixation, dehydration, and staining of cells for TEM analysis may affect cell morphology and ultrastructure and, thus, prevent the accurate determination of distinct S-l...

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Structural Reorganization of Phospholipid Headgroups upon Recrystallization of an S-Layer Lattice

Cited by 35 publications

References 50 publications

Are S-layers exoskeletons? The basic function of protein surface layers revisited

Are S-layers exoskeletons? The basic function of protein surface layers revisited

Rearrangement of Lipid Ordered Phases Upon Protein Adsorption Due to Multiple Site Binding

Small-Angle X-Ray Scattering for Imaging of Surface Layers on Intact Bacteria in the Native Environment

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