A5062124197- Biochemical and Molecular Research
- Advanced Electron Microscopy Techniques and Applications
- Porphyrin Metabolism and Disorders
- Fluorine in Organic Chemistry
- Enzyme Structure and Function
- Bacteriophages and microbial interactions
- RNA modifications and cancer
- RNA and protein synthesis mechanisms
- Chemical Reactions and Isotopes
- Genomics and Phylogenetic Studies
- Metalloenzymes and iron-sulfur proteins
- ATP Synthase and ATPases Research
- Tuberculosis Research and Epidemiology
- Microtubule and mitosis dynamics
- Geology and Paleoclimatology Research
- Plant Virus Research Studies
- Poxvirus research and outbreaks
- Pancreatic function and diabetes
- Cellular Mechanics and Interactions
- Cervical Cancer and HPV Research
- Bacterial Identification and Susceptibility Testing
- Fungal and yeast genetics research
- Protein Structure and Dynamics
- Microbial metabolism and enzyme function
- Click Chemistry and Applications
Institute of Science and Technology Austria
2024
University of Washington
2017-2022
Seattle University
2021
University of British Columbia
2016
McGill University
2014
McGill University Health Centre
2013
Abbott Fund
1989
CTP Synthetase (CtpS) is a universally conserved and essential metabolic enzyme. While many enzymes form small oligomers, CtpS forms large-scale filamentous structures of unknown function in prokaryotes eukaryotes. By simultaneously monitoring polymerization enzymatic activity, we show that inhibits CtpS's product, CTP, induces assembly. To understand how assembly used electron microscopy to define the structure polymers. This suggests sterically hinders conformational change necessary for...
Natural molecular machines contain protein components that undergo motion relative to each other. Designing such mechanically constrained nanoscale architectures with internal degrees of freedom is an outstanding challenge for computational design. Here we explore the de novo construction machinery from designed axle and rotor cyclic or dihedral symmetry. We find axle-rotor systems assemble in vitro vivo as designed. Using cryo-electron microscopy, these populate conformationally variable...
Poxviruses are among the largest double-stranded DNA viruses, with members such as variola virus, monkeypox virus and vaccination strain vaccinia (VACV). Knowledge about structural proteins that form viral core has remained sparse. While major have been annotated via indirect experimental evidence, their structures elusive they could not be assigned to individual features. Hence, which constitute layers of core, palisade layer inner wall, enigmatic. Here we show, using a multi-modal...
The extracellular matrix (ECM) serves as a scaffold for cells and plays an essential role in regulating numerous cellular processes, including cell migration proliferation. Due to limitations specimen preparation conventional room-temperature electron microscopy, we lack structural knowledge on how ECM components are secreted, remodeled, interact with surrounding cells. We have developed 3D-ECM platform compatible sample thinning by cryo-focused ion beam milling, the lift-out extraction...
The ability to precisely design large proteins with diverse shapes would enable applications ranging from the of protein binders that wrap around their target positioning multiple functional sites in specified orientations. We describe a backbone method for generating wide range rigid fusions between helix-containing and use it 75,000 structurally unique junctions monomeric homo-oligomeric de novo designed ankyrin repeat (RPs). Of junction designs were experimentally characterized, 82% have...
Significance An effective immune response depends on the proliferation of T cells, a process that requires enzyme CTP synthase 1 (CTPS1). Individuals lacking CTPS1 due to rare genetic disorder exhibit severe immunodeficiencies but lack other major clinical consequences; requirement for outside is met by second isoform, CTPS2. Inhibiting without affecting CTPS2 therefore promising strategy treating autoimmune disorders and cell cancers while avoiding off-target effects. We characterize both...
Many metabolic enzymes self-assemble into micron-scale filaments to organize and regulate metabolism. The appearance of these assemblies often coincides with large changes as in development, cancer, stress. Yeast undergo cytoplasmic acidification upon starvation, triggering the assembly many filaments. However, it is unclear how assemble at molecular level what their role yeast starvation response. CTP Synthase (CTPS) assembles across species. Here, we characterize vitro polymerization...
Mycobacteria produce an unusual, glycolylated form of muramyl dipeptide (MDP) that is more potent and efficacious at inducing NOD2-mediated host responses. We tested the importance this modified MDP in Mycobacterium tuberculosis by disrupting gene, namH, responsible for modification. In vitro, namH mutant did not N-glycolylated muropeptides, but there was no alteration colony morphology, growth kinetics, cellular or mycolic acid profile. Ex vivo, survived replicated normally murine human...
Patients with latent autoimmune diabetes in adults (LADA) express autoantibodies against the 65-kDa isoform of GAD (GADA). Intervention recombinant human GAD65 formulated aluminium hydroxide (GAD-alum) given twice subcutaneously to LADA patients at intervals 4 weeks was safe and did not compromise β-cell function a Phase II clinical trial. GADA affinity has been shown predict progression type 1 diabetes. Here, we asked whether affected by antigen-specific vaccination and/or associated...
Magnetotactic bacteria possess cellular compartments called magnetosomes that sense magnetic fields. Alignment of in the bacterial cell is necessary for their function, and this achieved through anchoring to filaments composed protein MamK. MamK an actin homolog polymerizes upon ATP binding. Here, we report structure filament at ∼6.5 Å, obtained by cryo-Electron Microscopy. This confirms our previously reported double-stranded, nonstaggered architecture, reveals molecular basis formation....
TestPack Chlamydia (Abbott Laboratories) is a rapid enzyme immunoassay for the direct antigen detection of trachomatis in endocervical specimens. The assay self-contained, requires no specialized equipment, and yields results less than 30 min. clinical performance versus chlamydial cell culture was evaluated with total 1,694 paired Discordant samples were further investigated by immunofluorescent staining Chlamydiazyme immunoassay, confirmatory procedures. sensitivity less-than-48-h-old...
Significance Actin filaments are dynamic cytoskeletal elements that assemble upon ATP binding. homologs present in all domains of life, and share a similar 3D structure the assembling subunit, but evolutionary changes to subunit have generated many different actin filament structures. The bacterial AlfA, which positions plasmids—small, circular DNA molecules encode important genes—ensures each daughter cell receives at least one copy division. AlfA is from other actins two critical ways: it...
Abstract Poxviruses are among the largest double-stranded DNA viruses with members such as Variola virus, Monkeypox virus and famous vaccination strain Vaccinia (VACV). Knowledge about structural proteins that form viral core, found in all infectious poxvirus forms, has remained sparse. While major core have been annotated via indirect experimental evidence, their structures elusive they could not be assigned to individual architectural features of core. Hence, which constitute layers...
Abstract The extracellular matrix (ECM) is a highly hydrated, three-dimensional network composed of various macromolecules and signaling factors. It serves as structural scaffold for cells plays an essential role in the regulation numerous cellular processes, including cell migration, adhesion, proliferation. Despite its importance metazoans, knowledge rudimentary on how components matrisome are secreted, remodeled, interact with each other surrounding cells. Specifically, exact molecular...
Abstract Natural nanomachines like the F 1 /F 0 -ATPase contain protein components that undergo rotation relative to each other. Designing such mechanically constrained nanoscale architectures with internal degrees of freedom is an outstanding challenge for computational design. Here we explore de novo construction rotary machinery from designed axle and ring components. Using cryoelectron microscopy, find axle-ring systems assemble as populate diverse rotational states depending on symmetry...
ABSTRACT Many metabolic enzymes self-assemble into micron-scale filaments to organize and regulate metabolism. The appearance of these assemblies often coincides with large changes as in development, cancer, stress. Yeast undergo cytoplasmic acidification upon starvation, triggering the assembly many filaments. However, it is unclear how assemble at molecular level what their role yeast starvation response. CTP Synthase (CTPS) assembles across species. Here, we characterize vitro...
Abstract Bacterial actins are an evolutionarily diverse family of ATP-dependent filaments built from protomers with a conserved structural fold. Actin-based segregation systems encoded on many bacterial plasmids and function to partition into daughter cells. The actin AlfA segregates by mechanism distinct other systems, dependent its unique dynamic properties. Here, we report the near-atomic resolution cryo-EM structure filament, which reveals strikingly divergent filament architecture...