Thomas Weiss - US grants

CRISP; Cell Membrane Lipids; Computer Programs; Computer Retrieval of Information on Scientific Projects Database; Computer software; Data; Data Collection; Data Set; Dataset; Funding; Future; Grant; Humidity; Hydration; Hydration status; Ice; Incidence; Institution; Investigators; Lipid Bilayers; Lipids; Liquid substance; Measurement; Measures; Membrane; Membrane Lipids; Methods; NIH; National Institutes of Health; National Institutes of Health (U.S.); Phase; Proteins; Protocol; Protocols documentation; Range; Research; Research Personnel; Research Resources; Researchers; Resources; Sampling; Software; Source; System; System, LOINC Axis 4; Temperature; United States National Institutes of Health; computer program/software; electron density; experiment; experimental research; experimental study; fluid; gene product; instrument; lipid bilayer membrane; liquid; membrane structure; research study

Absorption; Bone structure of radius; CRISP; Cell Communication and Signaling; Cell Signaling; Characteristics; Computer Retrieval of Information on Scientific Projects Database; Data; Equine; Equine Species; Equus caballus; Equus przewalskii; Ferritin; Fluorescence; Funding; Grant; Horse, Domestic; Horses; Hydrogen Oxide; Institution; Intracellular Communication and Signaling; Investigators; Ions; Lanthanides; Lanthanoid Series Elements; Lanthanoids; Lipids; Measures; Micelles; Modeling; NIH; National Institutes of Health; National Institutes of Health (U.S.); Phosphatides; Phospholipids; Process of absorption; Property; Property, LOINC Axis 2; Radial Bone; Radius; Radius Bone; Research; Research Personnel; Research Resources; Researchers; Resources; Reticuloendothelial System, Spleen; Sampling; Signal Transduction; Signal Transduction Systems; Signaling; Solutions; Source; Spleen; Suspension substance; Suspensions; Testing; Thinking; Thinking, function; United States National Institutes of Health; Water; Work; Yb element; Ytterbium; absorption; biological signal transduction; detector; experiment; experimental research; experimental study; improved; insight; interest; magnetic field; nano meter; nanometer; radius bone structure; research study; suspension

Absorption; CRISP; Collection; Computer Retrieval of Information on Scientific Projects Database; Count; Development; Electronics; Funding; Grant; Institution; Investigators; Ions; Measurement; Monitor; NIH; National Institutes of Health; National Institutes of Health (U.S.); Photons; Position; Positioning Attribute; Process of absorption; Research; Research Personnel; Research Resources; Researchers; Resources; Sampling; Scheme; Source; Standards; Standards of Weights and Measures; Thick; Thickness; United States National Institutes of Health; absorption; base; design; designing; detector; improved; prototype

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. After the start-up and initial commissioning of BL4-2, the position of the x-ray beam at the focal point in the hutch was measured for several days. The measurements showed that the horizontal beam position was stable within 140 microns and the vertical position of the beam moved up to 400 microns with clear diurnal characteristics. Thus, compared to the size of the focused beam (1.2 mm horizontal and 0.3 mm vertical) the horizontal movement is negligible, but the changes in the vertical beam position needed to be addressed. Variations in the pitch of the focusing mirror were identified as the major contributor to the observed beam motion. Local temperature control of the mirror cooling water was installed in early summer 2008 to reduce the temperature variation of the mirror cooling water and thus minimize the possible dependence of the mirror position due to thermal drift. A reduction was indeed observed (to 250 microns) but not to the required level. Current approaches include implementation of electronic active feedback of the mirror pitch motion.

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In the presence of water, aligned lipid membranes self-assemble in the vicinity of flat and smooth surfaces forming a smectic-C liquid crystal structure with water intercalated between the bilayers formed by the lipid molecules. By sandwiching hydrated lipids in between two substrates one can achieve several square-millimeter large defect-free monodomains of highly aligned lipid membranes. Using thin, x-ray transparent silicon-nitride windows as alignment substrate transmission SAXS experiments on such samples are possible. The small size and high intensity of the beam available at BL4-2 together with the large defect free domain size allows then to probe the structure in the plane of the membrane. In this project we investigated the change in the nearest neighbor distance between peptides inside the membrane in dependence on the thickness of the lipid and the peptide concentration. We find that the average distance between the proteins increases with increasing thickness of the bilayer. This effect is attributed to the increased membrane mediated repulsive interaction between the peptides due to the increased hydrophobic mismatch. We also found that a decrease in peptide concentration causes a larger than expected increase in the peptide-peptide distance, which could be caused by a concentration dependent boundary layer of lipids around the protein. We are currently working on a more detailed analysis of the data collected.

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The SSRL BTP staff provides each user group hands-on training on the effective use of the SMB SAXS/D instrument. All users first receive a brief safety orientation specific to BL4-2 and an overview of the instrument, including updates on recent equipment changes. The BTP staff discuss user experimental requirements, configure the instrument as necessary and train users. Users receive a tutorial on Blu-Ice software used for all types of experiment on BL4-2 with particular emphasis on a specific data collection ?tab? required for their data collection, for instance the solSAXS tab for solution scattering studies. They also receive instruction on sample-handling equipment and a tutorial on SAStool (formerly called MarParse), the data processing program for non-crystallined diffraction studies developed recently by the BTP staff. Users are instructed on initial steps of data analysis, such as inspecting data for possible radiation-induced aggregation and assessing data quality. The staff is also available to help users set up data collection strategies. The data processing program Primus, developed by an EMBL-Hamburg group, is used for data display and computing basic structural parameters such as radii of gyration (Rg). The BTP staff walks users through all the above by measuring first set of x-ray scattering data together. The staff also gives a short tutorial on Fit2D, developed at the European Synchrotron Radiation Facility, upon request. These hands-on training sessions are given to new as well as experienced user groups.

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We measured x-ray scattering intensities from a variety of commonly used materials for X-ray windows including silicon nitrite membranes, thin mica sheets and three types of thin-wall x-ray capillaries (glass, quartz and borosilicate). Silicon nitrite membranes give the lowest level of parasitic scattering over the entire Q-range primarily due to their extreme thinness (nominally 200 nm). Thin mica sheets (single crystal alumina silicate, 10-25 micron thick), especially those freshly cleaved to minimize surface scratches, exhibit a comparably low signal level in the small Q region as the silicon nitrite membranes, but scatter about an order of magnitude more at higher Q values. We observed unexpectedly large differences among the different capillaries due to the variations in wall thickness and different degree of amorphous structures. Quartz and borosilicate capillaries give a lower level of x-ray scattering than glass capillaries in the low Q-region, whereas glass capillaries give weaker and flatter scattering profile in the higher Q range. In general, the parasitic scattering signal at low Q values is dominated by the surface structures and depends on the surface quality of the window material as demonstrated by the significantly lower level of scattering from freshly cleaved mica sheets, whereas the signal level at higher Q values is primarily governed by the bulk material structures, thus depends on the thickness and composition of the window material. We conclude that one should take into account the range of momentum transfer of interest for the experiment for selecting the best window material.

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We continue to mitigate the beam positional instability issue, which were found last year at the new BL4-2 location. Earlier this year, we identified the major cause of the instability, whose magnitude is often as much as 1.5 times the full width half maximum vertical beam size in 24 hours, to be most likely the gradual thermal drifts of a few pieces of thick concrete floor moving at different rates in response to diurnal temperature fluctuation. We began adopting a mirror pitch feedback system very similar to those operating successfully on other SSRL insertion device stations. The first version involved a straight copy of the standard beam position monitor with beryllium signal blades coated with a thin layer of Ti working under helium atmosphere. This approach resulted in an improvement in beam stability, achieving ten micron stability over a 16 hour period, down from typical 0.2 mm overall drifts over the same period. Its use is, however, limited to shorter sample-to-detector distances due to the high back ground level given by the Ti coating at small scattering angles. We have recently modified this design to minimize scattering background. A new vacuum compatible housing has been built and different blade materials have been tested. It was found that un-plated, polished beryllium blades give an appropriate level of signal for the feedback system to work while keeping unwanted parasitic scattering at a tolerable level. The new blades are now being fabricated and finial version of the device will be installed and tested as the new blades become available.

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. : Members of the interleukin 1 (IL 1) family of cytokines play major roles in host defense and immune system regulation in infectious and inflammatory diseases. They activate the biological response in effector cells by binding to the extra cellular domain of two IL 1 receptor family members, the primary receptor and the co receptor, forming a heterotrimeric signaling holocomplex. Despite the importance and the long interest in IL 1 cytokine/receptor complexes, only the IL 1b/IL 1 receptor I (IL 1 RI) and IL 1Ra/IL 1 RI complexes have been characterized on a structural level to date;information on the molecular arrangement of the heterotrimeric complexes is not available. Il-33 is a recently discovered IL-1 like cytokine, which was shown to be involved in T-helper-cell type 2 mediated immune responses, such as asthma or allergy. We used small angle x-ray scattering in combination with NMR chemical shift perturbation data and detailed biochemical characterization to obtain a consistent model of the IL-33/ST2 complex in solution. The model shows that IL 33 forms a complex with ST2 that is similar to the IL 1b/IL 1 RI complex. We extended our SAXS analysis to the IL 33/ST2/IL 1RacP and IL 1b/IL 1 RI/IL 1RacP complexes and propose a general model of the molecular arrangement of the IL 1 trimeric signaling complexes.