A5009387019- Advanced Electron Microscopy Techniques and Applications
- HIV Research and Treatment
- Carbon Nanotubes in Composites
- Bacteriophages and microbial interactions
- Nanocluster Synthesis and Applications
- Supramolecular Self-Assembly in Materials
- Bacterial Genetics and Biotechnology
- HIV/AIDS drug development and treatment
- Gold and Silver Nanoparticles Synthesis and Applications
- Graphene research and applications
- Protein Structure and Dynamics
- Enzyme Structure and Function
- RNA and protein synthesis mechanisms
- RNA modifications and cancer
- Genomics and Chromatin Dynamics
- Electron and X-Ray Spectroscopy Techniques
- Photosynthetic Processes and Mechanisms
- Nanopore and Nanochannel Transport Studies
- Cytomegalovirus and herpesvirus research
- Photoreceptor and optogenetics research
- Quantum Dots Synthesis And Properties
- RNA Research and Splicing
- Signaling Pathways in Disease
- Endoplasmic Reticulum Stress and Disease
- Boron and Carbon Nanomaterials Research
Van Andel Institute
2017-2024
University of Pittsburgh
2010-2020
Pennsylvania State System of Higher Education
2016
Arizona State University
2007-2010
University of North Carolina at Chapel Hill
2004-2006
National Institute for Materials Science
2005
We utilize a peptide-based methodology to prepare diverse collection of double-helical gold nanoparticle superstructures having controllable handedness and structural metrics. These materials exhibit well-defined circular dichroism signatures at visible wavelengths owing the collective dipole-dipole interactions between nanoparticles. couple theory experiment show how tuning metrics structure helices results in predictable tailorable chirooptical properties. Finally, we experimentally...
Photon-to-matter chirality transfer offers both simplicity and universality to chiral synthesis, but its efficiency is typically low for organic compounds. Besides the fundamental importance of this process relevant understanding origin homochirality on Earth, new pathways imposing bias during chemical are essential a variety technologies from medicine informatics. The strong optical activity inorganic nanoparticles (NPs) affords photosynthetic routes superstructures using circularly...
Single-crystalline lanthanum hexaboride (LaB6) nanowires show excellent electric-field-induced electron emission following the Fowler–Nordheim scheme. The LaB6 grow in <001> crystallographic direction (see Figure) with diameters of about 20 nm. An current 30 nA from a single nanowire, corresponding to density 5 × 105 A cm–2, has been obtained.
Chiral nanoparticle assemblies are an interesting class of materials whose chiroptical properties make them attractive for a variety applications. Here, C18-(PEPAuM-ox)2 (PEPAuM-ox = AYSSGAPPMoxPPF) is shown to direct the assembly single-helical gold superstructures that exhibit exceptionally strong activity at plasmon frequency with absolute g-factor values up 0.04. Transmission electron microscopy (TEM) and cryogenic tomography (cryo-ET) results indicate single helices have periodic pitch...
Abstract The host cell factor cyclophilin A (CypA) interacts directly with the HIV-1 capsid and regulates viral infectivity. Although crystal structure of CypA in complex N-terminal domain protein (CA) has been known for nearly two decades, how modulates infectivity remains unclear. We determined cryoEM assembled at 8-Å resolution. exhibits a distinct CypA-binding pattern which selectively bridges CA hexamers along direction highest curvature. EM-guided all-atom molecular dynamics...
Abstract Formylpeptide receptors (FPRs) as G protein-coupled (GPCRs) can recognize formylpeptides derived from pathogens or host cells to function in defense and cell clearance. In addition, FPRs, especially FPR2, also other ligands with a large chemical diversity generated at different stages of inflammation either promote resolve order maintain balanced inflammatory response. The mechanism underlying promiscuous ligand recognition activation FPRs is not clear. Here we report cryo-EM...
Chemotactic responses in bacteria require large, highly ordered arrays of sensory proteins to mediate the signal transduction that ultimately controls cell motility. A mechanistic understanding molecular events underlying signaling, however, has been hampered by lack a high-resolution structural description extended array. Here, we report novel reconstitution array, involving receptor signaling domain, histidine kinase CheA, and adaptor protein CheW, as well density map core-signaling unit...
Significance During initiation of DNA replication in eukaryotes, the origin recognition complex, with Cdc6 and Cdt1, assembles an inactive Mcm2-7 double hexamer on dsDNA. Later, recruits Cdc45 GINS to form two active separate helicases. The Cdc45–Mcm2-7–GINS helicase encircles leading strand while excluding lagging strand. One fundamental unanswered questions is how each converts from binding dsDNA one single strands. structure reveals interacts key elements inside central channel, us...
Sub-100 nm hollow gold nanoparticle superstructures were prepared in a direct one-pot reaction. A gold-binding peptide conjugate, C6-AA-PEPAu (PEPAu = AYSSGAPPMPPF), was constructed and used to the simultaneous synthesis assembly of nanoparticles. Transmission electron microscopy tomography revealed that are uniform consist monodisperse nanoparticles arranged into spherical monolayer shell.
TRIM proteins play important roles in the innate immune defense against retroviral infection, including human immunodeficiency virus type-1 (HIV-1). Rhesus macaque TRIM5α (TRIM5αrh) targets HIV-1 capsid and blocks infection at an early post-entry stage, prior to reverse transcription. Studies have shown that binding of assembled is essential for restriction requires coiled-coil B30.2/SPRY domains, but molecular mechanism not fully understood. In this study, we investigated, by cryoEM...
The protein disaggregase ClpB hexamer is conserved across evolution and has two AAA+-type nucleotide-binding domains, NBD1 NBD2, in each protomer. In M. tuberculosis (Mtb), facilitates asymmetric distribution of aggregates during cell division to help the pathogen survive persist within host, but a mechanistic understanding been lacking. Here we report cryo-EM structures at 3.8- 3.9-Å resolution Mtb bound model substrate, casein, presence weakly hydrolyzable ATP mimic adenosine...
Abstract The heterodimeric eukaryotic Drs2p-Cdc50p complex is a lipid flippase that maintains cell membrane asymmetry. enzyme exists in an autoinhibited form the absence of activator and specifically activated by phosphatidylinositol-4-phosphate (PI4P), although underlying mechanisms have been unclear. Here we report cryo-EM structures intact isolated from S . cerevisiae apo PI4P-activated at 2.8 Å 3.3 resolution, respectively. reveal Drs2p C-terminus lines long groove cytosolic regulatory...
The current view is that eukaryotic replisomes are independent. Here we show Ctf4 tightly dimerizes CMG helicase, with an extensive interface involving Psf2, Cdc45, and Sld5. Interestingly, binds only one Pol α-primase. Thus, may have evolved as a trimer to organize two helicases α-primase into replication factory. In the 2CMG–Ctf43–1Pol factory model, CMGs nearly face each other, placing lagging strands toward center leading out sides. single centrally located prime both sister replisomes....