E3143-18b Standard Practice for Performing Cryo-Transmission Electron Microscopy of Liposomes vitrification~ transmission electron microscopes~
ASSISTANT PROFESSOR IN CRYO ELECTRON MICROSCOPY in Full Time, Academia, Life Sciences with University of California, Irvine. Apply Today.
Single-particle cryo-electron microscopy has become an indispensable technique in structural biology. In particular when studying membrane proteins, it allows the use of membrane-mimicking tools,...
Link to Pubmed [PMID] - 27667334. Protein Sci. 2017 01;26(1):113-121. The tremendous pandemic potential of coronaviruses was demonstrated twice in the last 15 years by two global outbreaks of deadly pneumonia. Entry of coronaviruses into cells is mediated by the transmembrane spike glycoprotein S, which forms a trimer carrying receptor-binding and membrane fusion functions. Despite their biomedical importance, coronavirus S glycoproteins have proven difficult targets for structural characterization, precluding high-resolution studies of the biologically relevant trimer. Recent technological developments in single particle cryo-electron microscopy allowed us to determine the first structure of a coronavirus S glycoprotein trimer which provided a framework to understand the mechanisms of viral entry and suggested potential inhibition strategies for this family of viruses. Here, we describe the key factors that enabled this breakthrough.. https://www.ncbi.nlm.nih.gov/pubmed/27667334 ...
Author(s): Jiang, Xi; Spencer, Ryan K; Sun, Jing; Ophus, Colin; Zuckermann, Ronald N; Downing, Kenneth H; Balsara, Nitash P | Abstract: Vesicle formation in a series of amphiphilic sequence-defined polypeptoid block co-polymers comprising a phosphonated hydrophilic block and an amorphous hydrophobic block, poly- N-(2-ethyl)hexylglycine- block-poly- N-phosphonomethylglycine (pNeh- b-pNpm), is studied. The hydrophobic/hydrophilic block ratio was varied keeping the total chain length of the co-polymers constant. A new approach for characterizing the vesicle membrane morphology based on low-dose cryogenic electron microscopy (cryo-EM) is described. The individual low-dose micrographs cannot be interpreted directly due to low signal-to-noise ratio. Sorting and averaging techniques, developed in the context of protein structure determination, were thus applied to vesicle micrographs. Molecular dynamic simulations of the vesicles were used to establish the relationship between membrane morphology and averaged
TY - JOUR. T1 - Structural studies of virus-antibody complexes by electron cryomicroscopy and X-ray crystallography. AU - Chiu, Wah. AU - Smith, Thomas. PY - 1994. Y1 - 1994. N2 - The combined use of electron cryomicroscopy and X-ray crystallography has recently provided unprecedented and unique structural information of virus-antibody complexes. Different kinds of viral proteins have been located and identified on the capsid surface, certain residues of the viral proteins involved in antibody interactions have been identified; the elbow angle of bound antibody has been measured; and the mechanism of antibody-mediated neutralization has been elucidated. Within the next few years, this combined methodology should help investigators resolve the structures of large macromolecular assemblies to even higher resolutions.. AB - The combined use of electron cryomicroscopy and X-ray crystallography has recently provided unprecedented and unique structural information of virus-antibody complexes. ...
As a member of the wwPDB, the RCSB PDB curates and annotates PDB data according to agreed upon standards. The RCSB PDB also provides a variety of tools and resources. Users can perform simple and advanced searches based on annotations relating to sequence, structure and function. These molecules are visualized, downloaded, and analyzed by users who range from students to specialized scientists.
Structural biology is undergoing a seismic shift as single-particle cryo-electron microscopy (cryo-EM) is increasingly becoming the technique of choice for scientists who want to study DNA, proteins and other biological molecules at atomic resolution. Having just recently broken the 3 Å (angstrom) barrier with the use of the Gatan K2 Summit® direct detection camera, a new structure shows that there is no longer a resolution gap between x-ray crystallography and cryo-EM.
Alon McCormick, course coordinator and IPrime NMP Program Leader. This course is intended to enable industrial and academic scientists and engineers with no prior knowledge of electron microscopy to gain insight into cryotechniques to image nanostructures in liquids, soft materials, and biological systems. After attending the course you will be better able to assess what experiments are feasible for samples of interest to you, and to estimate the benefits and costs of these approaches.. The main instructors are innovators and leaders in the field of cryo-electron microscopy, particularly in the study of soft materials, nanomaterials, and virus structure - Jayesh Bellare, Indian Institute of Technology, Bombay, Ishi Talmon, Technion, Israel Institute of Technology, Wei Zhang, U of MN CharFac & Institute for Molecular Virology.. Registration and fees ...
Addresses: UNIV PARIS SUD, EQUIPE PHYSICOCHIM SYST POLYPHASES, URA CNRS 1218, CHATENAY MALABRY, FRANCE. UNIV UPPSALA, INST PHYS CHEM, S-75121 UPPSALA, SWEDEN.Available from: 2008-10-17 Created: 2008-10-17 Last updated: 2011-03-21 ...
PhD Project - High resolution cryo-electron microscopy of clathrin cage networks at University of Warwick, listed on FindAPhD.com
TY - JOUR. T1 - Cryo-EM structure of oxysterol-bound human Smoothened coupled to a heterotrimeric Gi. AU - Qi, Xiaofeng. AU - Liu, Heng. AU - Thompson, Bonne. AU - McDonald, Jeffrey. AU - Zhang, Cheng. AU - Li, Xiaochun. PY - 2019/1/1. Y1 - 2019/1/1. N2 - The oncoprotein Smoothened (SMO), a G-protein-coupled receptor (GPCR) of the Frizzled-class (class-F), transduces the Hedgehog signal from the tumour suppressor Patched-1 (PTCH1) to the glioma-associated-oncogene (GLI) transcription factors, which activates the Hedgehog signalling pathway1,2. It has remained unknown how PTCH1 modulates SMO, how SMO is stimulated to form a complex with heterotrimeric G proteins and whether G-protein coupling contributes to the activation of GLI proteins3. Here we show that 24,25-epoxycholesterol, which we identify as an endogenous ligand of PTCH1, can stimulate Hedgehog signalling in cells and can trigger G-protein signalling via human SMO in vitro. We present a cryo-electron microscopy structure of human SMO ...
TY - JOUR. T1 - Localization of eukaryote-specific ribosomal proteins in a 5.5-Å cryo-EM map of the 80S eukaryotic ribosome. AU - Armache, Jean Paul. AU - Jarasch, Alexander. AU - Anger, Andreas M.. AU - Villa, Elizabeth. AU - Becker, Thomas. AU - Bhushan, Shashi. AU - Jossinet, Fabrice. AU - Habeck, Michael. AU - Dindar, Gülcin. AU - Franckenberg, Sibylle. AU - Marquez, Viter. AU - Mielke, Thorsten. AU - Thomm, Michael. AU - Berninghausen, Otto. AU - Beatrix, Birgitta. AU - Söding, Johannes. AU - Westhof, Eric. AU - Wilson, Daniel N.. AU - Beckmann, Roland. PY - 2010/11/16. Y1 - 2010/11/16. N2 - Protein synthesis in all living organisms occurs on ribonucleoprotein particles, called ribosomes. Despite the universality of this process, eukaryotic ribosomes are significantly larger in size than their bacterial counterparts due in part to the presence of 80 r proteins rather than 54 in bacteria. Using cryoelectron microscopy reconstructions of a translating plant (Triticum aestivum) 80S ribosome ...
Posted on behalf of Elena Orlova... Dear All, It is a pleasure to announce that we are running the next EMBO practical course on image processing for cryo-electron microscopy in Birkbeck College , ISMB, London . This 10 day course will be held in September (5 - 15), 2017. You can find our announcement on the following sites: Twitter ( https://twitter.com/EMBOevents/status/818487485814730759 ), Facebook ( https://www.facebook.com/events/590421591166869/ ) EMBO events calendar ( http://www.embo.org/events/events-calendar ). Birkbeck College (http://www.bbk.ac.uk/biology/about-us/events/image-processing-for-cryo-electron-microscopy-1) Deadline for applications: Monday 15 May 2017 The aim of the course is to teach the basic principles and practical aspects of image processing to bioscientists and structural biologists wishing to determine macromolecular structures by cryo electron microscopy (EM). The course will concentrate on processing of single particle images, and will be aimed at advanced PhD ...
The Robert P. Apkarian Integrated Electron Microscopy Core (IECM) facility at Cherry Logan Emerson Hall is expanding to the O. Wayne Rollins Research Center, according to Assistant Dean of Research at the Emory University School of Medicine Michael E. Zwick. ... ...
Mucins are large glycoproteins that coat the surface of cells in the respiratory, digestive, and urogenital tracts. The first insights into the packing and secretion of intestinal MUC2 in molecular terms have now been obtained. Purified MUC2-N protein was analyzed by electron microscopy and image processing, suggesting how MUC2-N is packed in granulae of goblet cells. Dysregulation of the normal |1000-fold expansion upon release could explain the extreme viscosity of the produced mucus seen in cystic fibrosis.
Single particle analysis is a group of related computerized image processing techniques used to analyze images from transmission electron microscopy (TEM). These methods were developed to improve and extend the information obtainable from TEM images of particulate samples, typically proteins or other large biological entities such as viruses. Individual images of stained or unstained particles are very noisy, and so hard to interpret. Combining several digitized images of similar particles together gives an image with stronger and more easily interpretable features. An extension of this technique uses single particle methods to build up a three-dimensional reconstruction of the particle. Using cryo-electron microscopy it has become possible to generate reconstructions with sub-nanometer resolution and near-atomic resolution first in the case of highly symmetric viruses, and now in smaller, asymmetric proteins as well. Single particle analysis can be done on both negatively stained and vitreous ...
The RyR1 acts as an intracellular calcium channel that allows passage of Ca2+ from the sarcoplasmic reticulum to the cytoplasm; this increase in cytosolic Ca2+ is required for excitation-contraction coupling. Certain mutations in RyR1 have been directly linked to malignant hyperthermia (MH) and central core disease. In a series of studies, the role of Mg2+ has been explored as it pertains to MH, and it has been determined that dysregulation of Mg2+ can even lead to MH in patients without mutations. Consequently, the aim of the study was to insert the RyR1 into nanodiscs, small, circular lipid bilayers used to solubilize membrane proteins, and to use cryo-electron microscopy to assess the conformation of the RyR1 in the presence of Mg2+ and AMP-PCP. Particle reconstruction generated a 9.0 Å resolution map that confirmed successful incorporation of the RyR1 into nanodiscs and allowed visualization of the RyR1 in a physiological closed state.
J Struct Biol. 2012 Jul;179(1):56-67. doi: 10.1016/j.jsb.2012.04.012. Epub 2012 May 1. Research Support, N.I.H., Extramural; Research Support, Non-U.S. Govt
So it is finally out: the cryoEM structure of Tet(O) on the ribosome we have collaborated on with Joachim Franks lab is finally published on in Nature Communications. Tet(O) is a bacterial translational GTPase that clears the ribosome from tetracycline antibiotic, and structural data provided in the paper shed light on the mechanism of Tet(O)-mediated resistance. Recently cryoEM of Tet(O)s close relative, Tet(M) was published by Beckmann and Wilson labs, so now one can compare the two. And yes, they look very similar. No surprise there. ...
Pre-mRNA splicing is executed by the spliceosome, which has eight major functional states each with distinct composition. Five of these eight human spliceosomal complexes, all preceding exon ligation, have been structurally characterized. In this study, we report the cryo-electron microscopy structures of the human post-catalytic spliceosome (P complex) and intron lariat spliceosome (ILS) at average resolutions of 3.0 and 2.9 Å, respectively. In the P complex, the ligated exon remains anchored to loop I of U5 small nuclear RNA, and the 3-splice site is recognized by the junction between the 5-splice site and the branch point sequence. The ATPase/helicase Prp22, along with the ligated exon and eight other proteins, are dissociated in the P-to-ILS transition. Intriguingly, the ILS complex exists in two distinct conformations, one with the ATPase/helicase Prp43 and one without. Comparison of these three late-stage human spliceosomes reveals mechanistic insights into exon release and spliceosome ...
Joachim Frank (Columbia University, New York, USA) is a pioneer of single particle reconstruction, which is the most used reconstruction method for 3DEM structures in EMDB and EM entries in PDB. And also, he is a develper of Spider, which is one of the most famous software in this field, and is used for some EM Navigor data (e.g. map projection/slice images ...
The use of 3D cryo-electron microscopy reconstruction (3DEM) methods to experimentally determine structures of biological macromolecules, complexes and machines is rapidly increasing in the structural biology community. For journal articles reporting new 3DEM structures via single particle, helical, electron crystallography, and sub-tomogram averaging methods, we find that the overall map-deposition rate to EM Data Bank (EMDB) is approaching 70%. However, the rate varies significantly per journal, and tends to be highest for journals with well-defined and consistently enforced 3DEM deposition policies in place ...
With our process, new types of proteins can be isolated from mixtures and characterized within a week," explains Daniel Rhinow from the Max Planck Institute of Biophysics. "To date, just the isolation of the proteins was often part of a doctorate lasting several years." Together with Andreas Terfort (Goethe University Frankfurt) and Andrey Turchanin (Friedrich Schiller University Jena), the idea evolved a few years ago of fishing the desired proteins directly out of mixtures by equipping a nanosheet with recognition sites onto which the target protein bonds. The researchers have now succeeded in making proteins directly available for examination using electron cryo-microscopy through a "smart nanosheet".. Cryo electron microscopy is based on the shock- reezing of a sample at temperatures below minus 150 degrees Celsius. During this process, the protein maintains its structure, no interfering fixing and coloring agents are needed, and the electrons can easily irradiate the frozen object. The ...
US Air Force Research Lab. Monday, April 24, 2017, Colloquia Auditorium. Electron microscopy has been one of the robust tools in characterizing the life cycle of viruses, such as Semliki Forest Virus (SFV), an alphavirus that belongs to Togavirus family and causes encephalitis in human. The viral particle of SFV is composed of a nucleocapsid enclosed by a lipid-anchored glycoprotein spikes and infects cell through clathrin-dependent endocytosis pathway where it releases the nucleocapsid into the cytoplasm after membrane fusion at the late endosome. Cryo-electron microscopy and single particle reconstruction revealed the structure of SFV virion that both the nucleocapsid and surface spikes adapted into icosahedral symmetry with T4 surface lattice and that the connection between nucleocapsid protein and C-terminal tail of the glycoprotein stabilizes the particle integrity. Mutation at nucleocapsid does not changed the assembly of the viral particle although truncation at the RNA-binding domain ...
With the rapid progresses in both instrumentation and computing, it is increasingly straightforward and routine to determine the structures of icosahedral viruses to subnanometer resolutions (6-10 Å)...
Mono- and Stereopictres of 5.0 Angstrom coordination sphere of Zinc atom in PDB 3dco: Drosophila Nod (3DC4) and Bovine Tubulin (1JFF) Docked Into The 11-Angstrom Cryo-Em Map of Nucleotide-Free Nod Complexed to the Microtubule
by Victor A. Kostyuchenko, Elisa X. Y. Lim, Shuijun Zhang, Guntur Fibriansah, Thiam-Seng Ng, Justin S. G. Ooi, Jian Shi & Shee-Mei Lok. Nature (2016) doi:10.1038/nature17994 Published online 19 April 2016. Zika virus (ZIKV), formerly a neglected pathogen, has recently been associated with microcephaly in fetuses1, and with Guillian-Barré syndrome in adults2. Here we present the 3.7 Å resolution cryo-electron microscopy structure of ZIKV, and show that the overall architecture of the virus is similar to that of other flaviviruses. Sequence and structural comparisons of the ZIKV envelope (E) protein with other flaviviruses show that parts of the E protein closely resemble the neurovirulent West Nile and Japanese encephalitis viruses, while others are similar to dengue virus (DENV). However, the contribution of the E protein to flavivirus pathobiology is currently not understood. The virus particle was observed to be structurally stable even when incubated at 40 °C, in sharp contrast to the less ...
Scientists have used cryo-electron microscopy to capture the first atomic-level images of the crystalline dendrites that can grow in batteries.
Cryo-electron microscopy (cryo-EM) is a structural technique that images biological macromolecules in native-like conditions, and has been widely applied to the study of viruses. Virus structures have been determined by cryo-EM at resolutions ranging from molecular (~30-50Angstrom) to near atomic (~4 angstrom).... ...
Most fellows will come directly from a PhD or MD program and have expertise in a wide range of innovative technologies. Their work will have a combination of novelty, originality and risk, factors that often lower the chances of obtaining support through traditional channels. Salk Fellows will be independent group leaders and will be appointed for an initial period of three years, which may be followed by a two-year extension.. Salks first Fellow in this new program, Dmitry Lyumkis, joined the Salk on July 1 from The Scripps Research Institute and has made groundbreaking innovations in biological imaging. He uses single-particle cryo-electron microscopy-a cutting-edge technology that enables the visualization of large proteins and protein complexes under near-native conditions-to build three-dimensional models of the imaged objects. The resulting 3D models, which can now be resolved at near-atomic resolution with select specimens, facilitate a better understanding of protein function and ...
FEI have recently collaborated with the ARC Centre of Excellence in Advanced Molecular Imaging (Imaging CoE) to test a new approach to optimise samples prior to preparing them for vitrification and subsequent cryo-transmission electron microscopy (cryo-EM).
A fundamental challenge in manufacturing virus-based products is achieving sufficient purity while maintaining virus integrity. TEM is a direct visual method that provides high-resolution morphology information on viruses and their associated impurities.. For viral characterization, Vironova services offer a complete EM analysis package that includes both negative stain transmission electron microscopy and cryo-transmission electron microscopy. Each of these methods provides powerful image datasets representative of the sample and a report that highlights the sample morphology with a graphical presentation of quantitative data and conclusions from the analysis. In addition to our TEM services, we also offer MiniTEM - a movable 25kV TEM microscope with a high level of automation and ~1nm resolution. MiniTEM allows a user-friendly electron microscopy technology for viral characterization to be put in the hands of any process developer in the gene therapy or vaccine field.. With MiniTEM you can ...
Amyloids are implicated in neurodegenerative diseases. Fibrillar aggregates of the amyloid-β protein (Aβ) are the main component of the senile plaques found in brains of Alzheimers disease patients. We present the structure of an Aβ(1-42) fibril composed of two intertwined protofilaments determined by cryo-electron microscopy (cryo-EM) to 4.0-angstrom resolution, complemented by solid-state nuclear magnetic resonance experiments. The backbone of all 42 residues and nearly all side chains are well resolved in the EM density map, including the entire N terminus, which is part of the cross-β structure resulting in an overall "LS"-shaped topology of individual subunits. The dimer interface protects the hydrophobic C termini from the solvent. The characteristic staggering of the nonplanar subunits results in markedly different fibril ends, termed "groove" and "ridge," leading to different binding pathways on both fibril ends, which has implications for fibril growth. ...
Introduction to Virus Structure Tutorial Jonathan King, Peter Weigele, Greg Pintilie, David Gossard (MIT) v.November, 2008 Virus Structure • Size вЂ" • Basic shape вЂ" вЂ" • 17 nm вЂ" 3000 nm diameter Rod-like “Spherical” Protective Shell - Capsid вЂ" Made of many identical protein subunits вЂ" Symmetrically organized вЂ" 50% of weight вЂ" Enveloped or non-enveloped • Genomic material вЂ" DNA or RNA вЂ" Single- or double-stranded Virus Structure • Virus capsids function in: вЂ" Packaging and protecting nucleic acid вЂ" Host cell recognition • Protein on coat or envelope “feels” or “recognizes” host cell receptors вЂ" Genomic material delivery • Enveloped: cell fusion event • Non-enveloped: more complex strategies & specialized structures Electron Microscopy Mitra, K. & Frank, J., 2006. Ribosome dynamics: insights from atomic structure modeling into cryo-electron microscopy maps. Annual review of ...
The International Union of Crystallography is a non-profit scientific union serving the world-wide interests of crystallographers and other scientists employing crystallographic methods ...
The anaphase-promoting complex/cyclosome (APC/C) is a ubiquitin ligase with essential functions in mitosis, meiosis, and G1 phase of the cell cycle. APC/C recognizes substrates via coactivator proteins such as Cdh1, and bound substrates are ubiquitinated by E2 enzymes that interact with a hetero-dimer of the RING subunit Apc11 and the cullin Apc2. We have obtained three-dimensional (3D) models of human and Xenopus APC/C by angular reconstitution and random conical tilt (RCT) analyses of negatively stained cryo-electron microscopy (cryo-EM) preparations, have determined the masses of these particles by scanning transmission electron microscopy (STEM), and have mapped the locations of Cdh1 and Apc2. These proteins are located on the same side of the asymmetric APC/C, implying that this is where substrates are ubiquitinated. We have further identified a large flexible domain in APC/C that adopts a different orientation upon Cdh1 binding. Cdh1 may thus activate APC/C both by recruiting substrates ...
These authors contributed equally. # Corresponding author). 1.Shen H*, Li Z*, Jiang Y*, Pan X*, Wu J, Cristofori-Armstrong B, Smith JJ, Chin YKY, Lei J, Zhou Q#, King GF#, Yan N#. Structural basis for the modulation of voltage-gated sodium channels by animal toxins. Science (New York, NY). 2018.. 2.Zhou Q#, Zhou N, Wang HW#. Particle segmentation algorithm for flexible single particle reconstruction. Biophys Rep. 2017;3(1):43-55.. 3.Yan Z*, Zhou Q*, Wang L*, Wu J*, Zhao Y, Huang G, et al. Structure of the Nav1.4-beta1 Complex from Electric Eel. Cell. 2017;170(3):470-82 e11.. 4.Shen H*, Zhou Q*, Pan X*, Li Z*, Wu J*, Yan N. Structure of a eukaryotic voltage-gated sodium channel at near-atomic resolution. Science (New York, NY). 2017;355(6328).. 5.Gong X*, Qian HW*, Zhou XH*, Wu JP*, Wan T*, Cao PP, Huang WY, Zhao X, Wang X, Wang P, Shi Y, Gao GF, Zhou Q#, Yan N#. Structural Insights into the Niemann-Pick C1 (NPC1)-Mediated Cholesterol Transfer and Ebola Infection. Cell. ...
Spiral phase plate (Vortex): Standard and Custom spiral phase plate. Spiral phase plate converts a Gaussian to a donut-shaped energy ring.
As a member of the wwPDB, the RCSB PDB curates and annotates PDB data according to agreed upon standards. The RCSB PDB also provides a variety of tools and resources. Users can perform simple and advanced searches based on annotations relating to sequence, structure and function. These molecules are visualized, downloaded, and analyzed by users who range from students to specialized scientists.
Background Low-density lipoprotein (LDL) particles, the major carriers of cholesterol in the human circulation, have a key role in cholesterol physiology and in the development of atherosclerosis. The most prominent structural components in LDL are the core-forming cholesteryl esters (CE) and the particle-encircling single copy of a huge, non-exchangeable protein, the apolipoprotein B-100 (apoB-100). The shape of native LDL particles and the conformation of native apoB-100 on the particles remain incompletely characterized at the physiological human body temperature (37°C). Methodology/Principal Findings To study native LDL particles, we applied cryo-electron microscopy to calculate 3D reconstructions of LDL particles in their hydrated state. Images of the particles vitrified at 6°C and 37°C resulted in reconstructions at ∼16 Å resolution at both temperatures. 3D variance map analysis revealed rigid and flexible domains of lipids and apoB-100 at both temperatures. The reconstructions ...
My lab uses cryo electron microscopy (Cryo-EM) to investigate the structure and function of challenging protein targets that are intractable with other structural biology techniques.
Kristina Kermanshahche demos Cryo-Electron Microscopy for mapping protein structures on the Intel® Scalable System Framework at Supercomputing 2016.
Nature Methods has named Cryo-Electron Microscopy the method of the year 2015. This structural technique, which was always a step behind
How is Ca2+ binding mechanically transduced into pore opening? Comparison of isolated gating ring x-ray structures obtained in the absence and presence of high Ca2+ shows little change in the layer formed by the RCK2 domains, whereas that formed by the four RCK1 domains seems to be expanded by ,10 Å (Yuan et al., 2011). Large conformational changes induced by Ca2+ have also been measured in isolated tetrameric gating rings in solution (Javaherian et al., 2011). Because this region of the gating ring is directly linked to the channels pore-forming helices, this expansion could represent the direct link between Ca2+ binding and the opening of the pore in BK channels (Savalli et al., 2006; Yusifov et al., 2008, 2010; Lee and Cui, 2010). However, the physiological relevance of these crystal structures and biochemical studies was limited by the fact that only part of such a complex channel was studied. Cryo-electron microscopy structures of the full-length Slo1 channel from A. californica have been ...
The biogenesis of secretory as well as transmembrane proteins requires the activity of the universally conserved protein-conducting channel (PCC), the Sec61 complex (SecY complex in bacteria). In eukaryotic cells the PCC is located in the membrane of the endoplasmic reticulum where it can bind to translating ribosomes for co-translational protein transport. The Sec complex consists of three subunits (Sec61alpha, beta and gamma) and provides an aqueous environment for the translocation of hydrophilic peptides as well as a lateral opening in the Sec61alpha subunit that has been proposed to act as a gate for the membrane partitioning of hydrophobic domains. A plug helix and a so-called pore ring are believed to seal the PCC against ion flow and are proposed to rearrange for accommodation of translocating peptides. Several crystal and cryo-electron microscopy structures revealed different conformations of closed and partially open Sec61 and SecY complexes. However, in none of these samples has the ...
This is essential for the development of new alloys with greater endurance.". "We have shown that its possible to localise hydrogen at atomic resolution -- at the scale of a single atom -- or at a nanometre (less than one-billionth of a metre) scale by combining different technologies in a closed and protected workflow.. "These include state-of-the-art cryo electron microscopy freezing techniques, low-temperature sample preparation in a cryo focused ion beam microscope, and inert cryo-transfer.. ###. The research, published in Science, involved scientists from the Oxford and Sheffield universities in the UK and ETH Zurich in Switzerland.. The UQ Centre for Microscopy and Microanalysis will present two Microscopy and Myscope outreach sessions at the World Science Festival Brisbane on March 25 and March 26. Details at https ...
Abstract: Type-A γ-aminobutyric (GABAA) receptors are ligand-gated chloride channels with a very rich pharmacology. Some of their modulators, including benzodiazepines and general anaesthetics, are among the most successful drugs in clinical use and are common substances of abuse. Without reliable structural data, the mechanistic basis for the pharmacological modulation of GABAA receptors remains largely unknown. Here we report several high-resolution cryo-electron microscopy structures in which the full-length human α1β3γ2L GABAA receptor in lipid nanodiscs is bound to the channel-blocker picrotoxin, the competitive antagonist bicuculline, the agonist GABA (γ-aminobutyric acid), and the classical benzodiazepines alprazolam and diazepam. We describe the binding modes and mechanistic effects of these ligands, the closed and desensitized states of the GABAA receptor gating cycle, and the basis for allosteric coupling between the extracellular, agonist-binding region and the transmembrane, ...
The goal of our work is to study the structure and function of Type 4 Secretion Systems from Gram-positive bacteria, which so far is poorly understood, even though these bacteria account for a very large fraction of multi-resistant bacterial hospital infections. The PhD project will involve methods in molecular biology, biochemistry and structural biology, such as cloning, protein _expression_ and purification, surface plasmon resonance, calorimetry as well as X-ray crystallography and cryo electron microscopy ...
While the author really starts off a little pessimistic regarding the challenges and necessary technology advances in NMR-type technologies the tone of the mass spectrometry experts is much more upbeat and optimistic. With the tools we have now for native complex mass spectrometry and crosslinking and cryo electron microscopy, maybe we dont need to wait for the next big breakthrough in NMR to fully elucidate protein complexes ...