scholarly journals Solution Structures of Bacillus anthracis Protective Antigen Proteins Using Small Angle Neutron Scattering and Protective Antigen 63 Ion Channel Formation Kinetics

Toxins ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 888
Author(s):  
Ariel Michelman-Ribeiro ◽  
Kenneth A. Rubinson ◽  
Vitalii Silin ◽  
John J. Kasianowicz
Keyword(s):  
Neutron Scattering ◽  
Bacillus Anthracis ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Protective Antigen ◽  
Structural Information ◽  
Lethal Factor ◽  
Channel Formation ◽  
Lipid Bilayer Membranes ◽  
Solution Structures

We are studying the structures of bacterial toxins that form ion channels and enable macromolecule transport across membranes. For example, the crystal structure of the Staphylococcus aureus α-hemolysin (α-HL) channel in its functional state was confirmed using neutron reflectometry (NR) with the protein reconstituted in membranes tethered to a solid support. This method, which provides sub-nanometer structural information, could also test putative structures of the Bacillus anthracis protective antigen 63 (PA63) channel, locate where B. anthracis lethal factor and edema factor toxins (LF and EF, respectively) bind to it, and determine how certain small molecules can inhibit the interaction of LF and EF with the channel. We report here the solution structures of channel-forming PA63 and its precursor PA83 (which does not form channels) obtained with small angle neutron scattering. At near neutral pH, PA83 is a monomer and PA63 a heptamer. The latter is compared to two cryo-electron microscopy structures. We also show that although the α-HL and PA63 channels have similar structural features, unlike α-HL, PA63 channel formation in lipid bilayer membranes ceases within minutes of protein addition, which currently precludes the use of NR for elucidating the interactions between PA63, LF, EF, and potential therapeutic agents.

scholarly journals Small-angle neutron scattering solution structures of NADPH-dependent sulfite reductase

2021 ◽  
Vol 213 (2) ◽  
pp. 107724
Author(s):  
Daniel T. Murray ◽  
Kevin L. Weiss ◽  
Christopher B. Stanley ◽  
Gergely Nagy ◽  
M. Elizabeth Stroupe
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Sulfite Reductase ◽  
Solution Structures

scholarly journals Complementing structural information of modular proteins with small angle neutron scattering and contrast variation

2008 ◽  
Vol 37 (5) ◽  
pp. 719-719 ◽  
Author(s):  
J. G. Grossmann ◽  
A. J. Callaghan ◽  
M. J. Marcaida ◽  
B. F. Luisi ◽  
F. H. Alcock ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Structural Information ◽  
Contrast Variation ◽  
Modular Proteins

Complementing structural information of modular proteins with small angle neutron scattering and contrast variation

2008 ◽  
Vol 37 (5) ◽  
pp. 603-611 ◽  
Author(s):  
J. G. Grossmann ◽  
A. J. Callaghan ◽  
M. J. Marcaida ◽  
B. F. Luisi ◽  
F. H. Alcock ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Structural Information ◽  
Contrast Variation ◽  
Modular Proteins

scholarly journals Small-angle neutron scattering studies on the AMPA receptor GluA2 in the resting, AMPA-bound and GYKI-53655-bound states

IUCrJ ◽  
2018 ◽  
Vol 5 (6) ◽  
pp. 780-793 ◽  
Author(s):  
Andreas Haahr Larsen ◽  
Jerzy Dorosz ◽  
Thor Seneca Thorsen ◽  
Nicolai Tidemand Johansen ◽  
Tamim Darwish ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Ampa Receptor ◽  
Small Angle ◽  
Resting State ◽  
Small Angle Neutron Scattering ◽  
Solution Structure ◽  
Compact Form ◽  
Allosteric Modulator ◽  
Solution Structures ◽  
Negative Allosteric Modulator

The AMPA receptor GluA2 belongs to the family of ionotropic glutamate receptors, which are responsible for most of the fast excitatory neuronal signalling in the central nervous system. These receptors are important for memory and learning, but have also been associated with brain diseases such as Alzheimer's disease and epilepsy. Today, one drug is on the market for the treatment of epilepsy targeting AMPA receptors, i.e. a negative allosteric modulator of these receptors. Recently, crystal structures and cryo-electron microscopy (cryo-EM) structures of full-length GluA2 in the resting (apo), activated and desensitized states have been reported. Here, solution structures of full-length GluA2 are reported using small-angle neutron scattering (SANS) with a novel, fully matched-out detergent. The GluA2 solution structure was investigated in the resting state as well as in the presence of AMPA and of the negative allosteric modulator GYKI-53655. In solution and at neutral pH, the SANS data clearly indicate that GluA2 is in a compact form in the resting state. The solution structure resembles the crystal structure of GluA2 in the resting state, with an estimated maximum distance (D max) of 179 ± 11 Å and a radius of gyration (R g) of 61.9 ± 0.4 Å. An ab initio model of GluA2 in solution generated using DAMMIF clearly showed the individual domains, i.e. the extracellular N-terminal domains and ligand-binding domains as well as the transmembrane domain. Solution structures revealed that GluA2 remained in a compact form in the presence of AMPA or GYKI-53655. At acidic pH only, GluA2 in the presence of AMPA adopted a more open conformation of the extracellular part (estimated D max of 189 ± 5 Å and R g of 65.2 ± 0.5 Å), resembling the most open, desensitized class 3 cryo-EM structure of GluA2 in the presence of quisqualate. In conclusion, this methodological study may serve as an example for future SANS studies on membrane proteins.

scholarly journals Nanoscale investigation of polymer cement concretes by small angle neutron scattering

2017 ◽  
Vol 24 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Massimo Rogante ◽  
Irina K. Domanskaya ◽  
Ekaterina S. Gerasimova ◽  
Adél Len ◽  
László Rosta ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Structural Information ◽  
Fractal Dimensions ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Different Types ◽  
Ecological Criteria ◽  
Nanoscale Level

AbstractAn analysis of dense cements, such as polymer cement concrete, is made to produce original innovative components for different types of constructing materials. These materials present good functional properties (ageing resistance, crack formation resistance, hardness, and stability of mechanical modules) and can be used for various applications. In this paper, experimental tests on Portland cement with added γ-Al2O3 and redispersible dry polymer performed using small angle neutron scattering are reported. The objective of the investigation was to assess the key parameters of the material (e.g., porosity, fractal dimensions, and size distribution) at the nanoscale level as well as to obtain useful structural information for expanding the possibility of applications. The results obtained can contribute to the optimisation of the consistency of the material, the design of operating conditions of elements of structures and facilities, and the design of the procedures that support ecological criteria and enhance quality and safety levels.

scholarly journals Small-angle neutron scattering solution structures of NADPH-dependent sulfite reductase

2020 ◽  
Author(s):  
Daniel T Murray ◽  
Kevin Weiss ◽  
Christopher B Stanley ◽  
Gergely Nagy ◽  
M. Elizabeth Stroupe
Keyword(s):  
Electron Transfer ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Single Copy ◽  
Sulfite Reductase ◽  
Solution Structures ◽  
Contrast Matching ◽  
First Time ◽  
Binding Position

Sulfite reductase (SiR), a dodecameric complex of flavoprotein reductase subunits (SiRFP) and hemoprotein oxidase subunits (SiRHP), reduces sulfur reduction for biomass incorporation. Electron transfer within SiR requires intra- and inter-subunit interactions that are mediated by the relative position of each protein, governed by flexible domain movements. Using small-angle neutron scattering, we report the first solution structures of SiR heterodimers containing a single copy of each subunit. These structures show how the subunits bind and how both subunit binding and oxidation state impact SiRFP's conformation. Neutron contrast matching experiments on selectively deuterated heterodimers allow us to define the contribution of each subunit to the solution scattering. SiRHP binding induces a change in the position of SiRFP's flavodoxin-like domain relative to its ferredoxin-NADP+ reductase domain while compacting SiRHP's N-terminus. Reduction of SiRFP leads to a more open structure relative to its oxidized state, re-positioning SiRFP's N-terminal flavodoxin-like domain towards the SiRHP binding position. These structures show, for the first time, how both SiRHP binding to, and reduction of, SiRFP positions SiRFP for electron transfer between the subunits.

scholarly journals Small-angle Neutron Scattering Shows that the Solution Structures of the Bacterial Mg2+-Channel CorA are Overall Similar with and without Mg2+Bound

2020 ◽  
Vol 118 (3) ◽  
pp. 12a
Author(s):  
Lise Arleth ◽  
Nicolai T. Johansen ◽  
Tone Bengtsen ◽  
Andreas Haahr Larsen ◽  
Frederik Tidemand ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Solution Structures

scholarly journals Using Rheo-Small-Angle Neutron Scattering to Understand How Functionalised Dipeptides Form Gels

2020 ◽  
Vol 02 (02) ◽  
pp. 108-115
Author(s):  
Kate McAulay ◽  
Lisa Thomson ◽  
Lionel Porcar ◽  
Ralf Schweins ◽  
Najet Mahmoudi ◽  
...  
Keyword(s):  
Molecular Weight ◽  
3D Printing ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Structural Information ◽  
Applied Strain ◽  
Low Molecular Weight

We explore the use of rheo-small-angle neutron scattering as a method to collect structural information from neutron scattering simultaneously with rheology to understand how low-molecular-weight hydrogels form and behave under shear. We examine three different gelling hydrogel systems to assess what structures are formed and how these influence the rheology. Furthermore, we probe what is happening to the network during syneresis and why the gels do not recover after an applied strain. All this information is vital when considering gels for applications such as 3D-printing and injection.

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